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Machine
12-22-2012, 07:58 PM
I know this question will rank way up there as a Retardo Montalban question, but can someone explain to me exactly why surface grinders and surface grinding in general is so important? I see it discussed all the time and I see these really fancy, really expensive surface grinders in use at machine shops (in pictures, videos etc, not in person). But I never really understood why they are so important. If a surface needs to be ground, why not just mill it? Why not turn it on a lathe? Why not plane it down with a shaper? All I can think of is that grinding is appropriate (and necessary) if you're working with really hard metal that will damage or destroy conventional cutting bits made of tool steel. I can see where it would be necessary there. But heck, how often are you making a piece out of tungsten or something similar?

Another problem I see with grinding is that the grinder wheels are made of granulated stone that wears away as it grinds. I would think the wheel would get slightly smaller with every pass, complicating the matter of getting an even/parallel cut every time. Obviously it's a workable problem, but doesn't this complicate matters when grinding? Confused, and always have been about the whats, whys and wheres of surface grinding.

John Stevenson
12-22-2012, 08:04 PM
It's a finishing program that gets very fine surface finishes.
Mill leaves tool marks and each one will probably be a few tenths. deep

KiddZimaHater
12-22-2012, 08:14 PM
Grinding heat-treated tool steel.
Surface finish
Accuracy
Making special tooling
And for making sweet punches:
http://img26.imageshack.us/img26/6827/punchweb.jpg

sasquatch
12-22-2012, 08:37 PM
Good question Machine, i don't think i have seen this asked here before.

macona
12-22-2012, 08:41 PM
Wheel wear is not as big of an issue as you would think. First, remember that grinding is mostly a finishing process. You are usually taking off thousandths at a time, at most. Also when grinding you do not step over the full width of the wheel, more like .040 to .050 at a time. This way only the leading edge of the stone takes the brunt of the wear. By the time you take a full pass the back edge of the stone has hardly been touched by metal.

And like the other have said, you can get finishes and tolerances you just cant get on a mill or lathe with a grinding process.

That being said, I sold my grinder a few months ago. I just never used it and needed the space for the laser cutter. If I need one that badly I can find someone around here, I am sure.

Mcgyver
12-22-2012, 11:41 PM
finish, accuracy, ability to machine hardened surfaces.

wheel wear not an issues macona described.

I've never surface ground tungsten, but done lots of case hardened and hardened tool steel.....but doesn't have to be that, you still get the finish and accuracy advantage with mild steel, cast iron etc.

Like so much we collect in our shops, do you absolutely have to have one? no, but it sure is nice and mine sees a fair bit of use. Then again I could take up golf and not need anything in my shop....so 'need' doesn't carry the day for anything in my shop. part of the fun for me at least is expanding the capabilities and skills....thats enough of a reason to get one :)

tdmidget
12-22-2012, 11:42 PM
I know this question will rank way up there as a Retardo Montalban question, but can someone explain to me exactly why surface grinders and surface grinding in general is so important? I see it discussed all the time and I see these really fancy, really expensive surface grinders in use at machine shops (in pictures, videos etc, not in person). But I never really understood why they are so important. If a surface needs to be ground, why not just mill it? Why not turn it on a lathe? Why not plane it down with a shaper?

Not Retardo Montalbon question but one that needs to be answered here from time to time. Grinding is more than a finish and more than a way to cut hard materials. Grinding machines are typically orders of magnitude more accurate than lathes and mills. It is not at all unusual for a grinding machine of recent ( last 50 yrs) to be capable of working to .00001 when new. I have run several machine with .00001 graduations and new machines are even more capable. This why a toolpost grinder is just a pretender in the grinding world. It is no more accurate than the lathe with any other cutting tool. A cylindrical grinder on the other hand should be accurate to a couple of tenths repeatedly.


All I can think of is that grinding is appropriate (and necessary) if you're working with really hard metal that will damage or destroy conventional cutting bits made of tool steel. I can see where it would be necessary there. But heck, how often are you making a piece out of tungsten or something similar?

Tungten would rarely be machined in the pure form. It is very commonly alloyed with copper to produce a dense, hard, machinable alloy used in applications varying from rocket engines to darts, yes, those thrown in your favorite pub. Serious cutting of very hard materials is usually left to EDM.

Another problem I see with grinding is that the grinder wheels are made of granulated stone that wears away as it grinds. I would think the wheel would get slightly smaller with every pass, complicating the matter of getting an even/parallel cut every time. Obviously it's a workable problem, but doesn't this complicate matters when grinding? Confused, and always have been about the whats, whys and wheres of surface grinding.
Uh ,No. Grinding wheels are most certainly NOT "granulated stone". They are made of various abrasives, bonds, and structures. They are NOT "stone" in any form. Modern abrasives are man made , even most diamond abrasives are man made. The wheel does not get smaller with every pass because the entire wheel is not cutting. The leading edge does the vast majority of the work and does indeed wear. The area behind the leading edge , unworn, finishes the job. As this area wears, as it inevitably will, the next area will bring the part to size. Therefore if a wheel is one inch in width and is cutting in both directions at .1 crossfeed, it will take at least 5 passes in each direction to affect size. In fact if the wheel is properly chosen, it may take many more than that.,

Paul Alciatore
12-23-2012, 12:03 AM
I know .....
Another problem I see with grinding is that the grinder wheels are made of granulated stone that wears away as it grinds. I would think the wheel would get slightly smaller with every pass, complicating the matter of getting an even/parallel cut every time. Obviously it's a workable problem, but doesn't this complicate matters when grinding? Confused, and always have been about the whats, whys and wheres of surface grinding.

Years ago, I used to worry about the same thing with all cutting tools. I mean, if you start to turn a diameter with a single point tool, it will wear while you are cutting. Wouldn't the end of the cut have a larger diameter than the start? Well, it dies wear. But in practice, it is not a real problem unless you are taking really heavy cut and then you are probably going to see other problems that will completely hide any small differences in diameter.

In short, theory says yes, but practice says it is so minimal that you need not worry.

Grinding wheels take very small amounts off in one pass and the wear on the wheel is very slight. Like others have already pointed out, the wheel cuts mostly on the leading edge and is wide enough to allow you to finish the job before the wear reaches too far in. And you should dress the wheel before this happens.

Black_Moons
12-23-2012, 12:41 AM
You can have a diamond point mounted on the grinder table that the wheel goes over, This dressed the wheel to a known size and makes it 'flat', So you can know your wheel is true and what exact size it is. Thats one of the reasons surface grinding wheels don't have accuracy problems as they wear, They can be easily 'resharpened' to flat (Or even to a shape!) every few passes while still on the machine.

oldtiffie
12-23-2012, 12:51 AM
Select the surface finish/texture you require and use the range of processing (grinding included) and take notice of the "machinability" (including "hardness") required for the job.

http://en.wikipedia.org/wiki/Surface_finish

http://www.roymech.co.uk/Useful_Tables/Surface_Texture/Sur_Fin_Values.html

http://www.google.com.au/#hl=en&tbo=d&rlz=1R2IRFC_enAU360&sclient=psy-ab&q=what+is+surface+finish&rlz=1R2IRFC_enAU360&oq=surface+fins&gs_l=hp.1.2.0i10l2j0i10i30j0i30.0.0.1.3467.0.0.0.0 .0.0.0.0..0.0.les%3B..0.0...1c.noGmB4Quyeo&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&bvm=bv.1355534169,d.dGY&fp=def9f3f538eb70d&bpcl=40096503&biw=1920&bih=846

Toolguy
12-23-2012, 02:48 AM
It is not a dumb question. The surface grinder is one of the least understood machines in a shop usually. The reason is that most people don't know what to do with it. There is the making of things very flat to an accurate thickness. Then there is form grinding where you shape the wheel with a special diamond dresser to make angles, a concave or convex radius, or a combination with the angles being tangent to the curves. There is also tool & cutter grinding with the correct fixtures, and making dowel pins and step pins with a spin jig. Also you can turn down the shank of an end mill or tap if you need to cut deeper than the flutes allow. You can grind special shaped punches and dies for punch press dies. You can make any shape or size of rotary broach. You can sharpen a reamer or make it a special size and/or turn a pilot on the end.
The list goes on and on but you get the idea, it's not just for making things flat. I would hate to try to run a shop without a surface grinder.

Jaakko Fagerlund
12-23-2012, 05:06 AM
If you ever take a freshly milled surface to a grinder, you may notice that the small looking ridges left by the milling cutter are easily 0.02 to 0.2 mm deep, even a finish cut with a sharp tool leaves around 0.01 to 0.05 mm. And the block you milled on both sides to get it flat and/or even thickness - well, it isn't flat nor even most probably, if done in a vise.

If you want good sliding surfaces, the ground finish is good for that as it bears loads very well.

And sure the grinding wheel will eventually wear down, but as has been said, it takes some time and grinding to do that. On some machines (like CNC and automated manual machines) there is a wheel dressing unit, basically one slide with a hydraulic or electric feed that moves a diamond across the wheel to dress it. For example, on a Johansson automatic grinder I can set how much the diamond will dress and how often (like 0.005 mm off after 0.1 mm of grinding). The machine drops the Y axis (the wheel) the same amount as I dress, so the wheel stays in the same place relative to the workpiece.

If the wheel wears more than expected (wrong wheel type, lots of rough grinding), then the part will be oversized. But, there is an easy fix: Just grind more :)

Black Forest
12-23-2012, 05:44 AM
Thank you for asking this question. Now I have to go buy a surface grinder. I don't want any of you guys coming into my shop and noting that there is no surface grinder and thinking to yourself....hmm, no surface grinder in sight. This guy is just a farmer working to farmer tolerances.

Can anyone recommend a grinder for my use? I am in Germany so probably a European will need to answer this question. Maybe Jaako!

I have thought recently that a surface grinder should be my next acquisition maybe just before the CNC plasma table.

MrFluffy
12-23-2012, 06:36 AM
Ive been looking at this in anticipation, and as elsewhere my surface grinder was hiab'd off the truck yesterday.
Besides making things flat and smooth (very useful to me) like clutch plate steels and shims etc, I have a jig to hold mill tooling for sharpening at defininate angles to use it to touch up some very blunt big endmill's, and I'm on the hunt for a spindexer to mount on it to make hard round things smaller.
I already want to take my straight drill shanks to collet sizes so I can hold them all in standard collets.
I'm sure the list will grow when its under power and in place!

PixMan
12-23-2012, 08:27 AM
Thank you for asking this question. Now I have to go buy a surface grinder. I don't want any of you guys coming into my shop and noting that there is no surface grinder and thinking to yourself....hmm, no surface grinder in sight. This guy is just a farmer working to farmer tolerances.

Can anyone recommend a grinder for my use? I am in Germany so probably a European will need to answer this question. Maybe Jaako!

I have thought recently that a surface grinder should be my next acquisition maybe just before the CNC plasma table.

You are just too funny! :D

Clearly you have identified a problem (no surface grinder) and are heading to a solution. Look for a good Mägerle, Jung, Blohm, Schaudt or other good German, Swiss or Austrian machine.

Happy Christmas BF!

vpt
12-23-2012, 09:37 AM
Anyone want to buy my surface grinder? I've owned it for a few years now and never even powered it. :)

http://img297.imageshack.us/img297/7453/ebay003052.jpg

Mike Hunter
12-23-2012, 10:25 AM
A few years ago a buddy of mine offered me a surface grinder; and like you, I thought well, that’s nice, but I really don’t have the use for one.

Now it has become an indispensable part of the shop, so much so that I bought a second one.

As with all tools, let your imagination be your guide as to the possibilities.

Adding to what has already been posted: making sure flat parts are flat how about taking .0015 off a delicate hardened part, grinding a woodruff cutter to a custom thickness. Grinding a custom radius on cutters, need to take .005 off a washer..no problem. Plunge grinding a radius or step….

Again, let your imagination be your guide

Jimmer12
12-23-2012, 10:55 AM
If you make any of your own tooling, like parallels, 123's angle bars, etc, you are sunk if you don't have a grinder.

I think you will also notice differing opinions on the necessity of grinders based on their experience and training. I know general machinists that are incredible with a lathe or mill, but have hardly ever ground anything. On the other hand I have never worked in a machine job shop, and have only worked in mould making and tool and die shops. Every place I've worked had at least double the number of grinders compared to lathes. We would barely ever make anything on a lathe, but our grinders would be making sparks all shift long. It's impossible to run a mould shop without a very good grinding area.

Machine
12-23-2012, 11:38 AM
Wow, thanks to everyone for all the great info. I feel at least a little more educated now about the grinder. One thing I didn't realize is that the work is passed under the stone parallel with the wheel's axis of rotation. I thought the work was moved under the stone perpendicular to its axis of rotation. So I can see where the wear on the stone would be less of an issue than I thought, especially as you guys have pointed out, when very small amounts are cut with each pass.

I just remember when I worked for a professor for a few summers doing basic machining on the vertical mill and most of the parts I would produce were aluminum. And we always had nice new cutter bits. I could get the surface of the aluminum pretty flat and pretty mirror-like, other than the normal swirled machining patterns in it. Of course I realized it wasn't perfectly flat on a microscopic level. As I dragged my fingernail across it, I could feel very light ridges, but overall I'd say there was less than 0.0005 of imperfection in the surface. We never had any need to produce anything more precise than that, so there was no need for a grinder.

I guess what you guys are saying is that when you're machining down to the 0.0001" (0.0025mm) level or less, that's when this super precise cutting instrument comes into play. It also allows machining of tool steel for all sorts of purposes. Sharpening or modifying cutter bits, creating punch die parts (something I can really see would be valuable). That makes sense.

One question though, don't they finish grind the beds and ways on lathes and mills? Didn't they used to hand scrape these surfaces in the past? Hand scraping has a much rougher finish than grinding, and yet it was considered acceptable back in the day for building precision machining tools. Why is that?

rode2rouen
12-23-2012, 11:55 AM
Wow, thanks to everyone for all the great info. I feel at least a little more educated now about the grinder. One thing I didn't realize is that the work is passed under the stone parallel with the wheel's axis of rotation. I thought the work was moved under the stone perpendicular to its axis of rotation. So I can see where the wear on the stone would be less of an issue than I thought, especially as you guys have pointed out, when very small amounts are cut with each pass.



While you may think it is just semantics, industrial grinding machines use abrasive wheels, not stones.


Rex

bborr01
12-23-2012, 11:58 AM
Some of the grinder hands that I used to work with referred to grinding as the "black art of grinding". Ask 10 tool and diemakers how they would do a job and get 10 different answers. Ask 10 grinder hands how to do a job and get 30 answers. Also as someone mentioned in a previous post, most job shops don't do a huge amount of all around grinding, or lathe work for that matter.

Another thing rarely mentioned here is grinder temperature. As a grinder warms up, especially a surface grinder, the way oil under the table thins out as it heats up from operating the grinder. Therefore if you grind all morning and are close to size when lunch time arrives, don't forget to back off the wheel a little and "sneak up" on it or you will be undersize.

Brian

Mcgyver
12-23-2012, 11:59 AM
One question though, don't they finish grind the beds and ways on lathes and mills? Didn't they used to hand scrape these surfaces in the past? Hand scraping has a much rougher finish than grinding, and yet it was considered acceptable back in the day for building precision machining tools. Why is that?

the full explanation is long one, but scraping is very current in how machine tools are finished, and it is not rough. if you grind say a lathe bed, how are you going to machine the bottom of the carriage to fit perfectly, to a tenth? It is easy to grind the long lathe bed, but on a quality lathe the mating parts are still scraped in.

Its a big mistake to think grinding is more accurate or better than scraping, often the opposite is true. They are two different techniques each with strengths and weaknesses - the task at hand determines which is preferable to use.


I guess what you guys are saying is that when you're machining down to the 0.0001" (0.0025mm) level or less, that's when this super precise cutting instrument comes into play. It also allows machining of tool steel for all sorts of purposes. Sharpening or modifying cutter bits, creating punch die parts (something I can really see would be valuable). That makes sense.

its not just to machine to .0001", its AND/OR......machine very accurately (better than mill) and/or better finish and/or hardened items.

The other point to remember is the surface grinder involves much lighter cuts and therefor less force than the mill is designed for. Needing to only handle a fraction of the forces means you can use lighter precision tooling you can't use on the mill; mag chucks, precision vises, mag v blocks, mag parallels, sine tables precision angle plates etc etc etc. All these have certain advantages....so its just not as simple as concluding surface grinding is for hardened items or .0001" items

Sharpening cutters generally requires a tool and cutter grinder; although there are ways to do some of this on a surface grinder. This is another machine the definitely belongs in the home shop; better economics and better work results imo.

lazlo
12-23-2012, 03:58 PM
the full explanation is long one, but scraping is very current in how machine tools are finished, and it is not rough. if you grind say a lathe bed, how are you going to machine the bottom of the carriage to fit perfectly, to a tenth? It is easy to grind the long lathe bed, but on a quality lathe the mating parts are still scraped in.

Plus, the vast majority of machine ways are induction hardened, which are impractical to scrape, even with carbide inserts. The fitting is done on the soft cast iron saddles, typically.

That's why more and more machines come with Turcite saddles, linear bearings, and pressurized oil slides. No hand-scraping, which is practically a lost art.

tdmidget
12-23-2012, 04:19 PM
"
Wow, thanks to everyone for all the great info. I feel at least a little more educated now about the grinder. One thing I didn't realize is that the work is passed under the stone parallel with the wheel's axis of rotation. I thought the work was moved under the stone perpendicular to its axis of rotation. So I can see where the wear on the stone would be less of an issue than I thought, especially as you guys have pointed out, when very small amounts are cut with each pass."

The term "stone" has no place in grinding. Natural abrasives are a thing of the past with exception of some diamond wheels , though most of those are man made. The modern grinding wheel has no more relation to "stone" than than a formula one car to a horse and buggy. The only use of "stone" in abrasive work is for small hand held shapes for deburring or hand polishing and knife sharpening.

tdmidget
12-23-2012, 04:27 PM
Some of the grinder hands that I used to work with referred to grinding as the "black art of grinding". Ask 10 tool and diemakers how they would do a job and get 10 different answers. Ask 10 grinder hands how to do a job and get 30 answers. Also as someone mentioned in a previous post, most job shops don't do a huge amount of all around grinding, or lathe work for that matter.

Another thing rarely mentioned here is grinder temperature. As a grinder warms up, especially a surface grinder, the way oil under the table thins out as it heats up from operating the grinder. Therefore if you grind all morning and are close to size when lunch time arrives, don't forget to back off the wheel a little and "sneak up" on it or you will be undersize.

Brian

This is one of the frustrating things about learning grinding of any kind. As soon as guy makes a few good parts he claims to be an expert. He often has no idea what worked and hems and haws when asked. Therefore he cannot transfer knowledge to another, because he doesn't really have any. Trying to learn in this environment is very frustrating when each guy tells a different story and none really want to share what they do know or admit how little they do know. The best sources I have found are the manufacturers. They want you to succeed and use their products. Companies like Norton have real experts who can give real information and teach. There are a few good books on the subject but mostly they are very general in nature.

bborr01
12-23-2012, 05:55 PM
This is one of the frustrating things about learning grinding of any kind. As soon as guy makes a few good parts he claims to be an expert. He often has no idea what worked and hems and haws when asked. Therefore he cannot transfer knowledge to another, because he doesn't really have any. Trying to learn in this environment is very frustrating when each guy tells a different story and none really want to share what they do know or admit how little they do know. The best sources I have found are the manufacturers. They want you to succeed and use their products. Companies like Norton have real experts who can give real information and teach. There are a few good books on the subject but mostly they are very general in nature.

TD,

Most of the guys that I worked with were pretty good at sharing their knowledge. We had factory reps come in fairly often but a lot of the time they would deal more with the engineers, leadmen, etc. and sometimes that knowledge didn't filter down.

As far as my grinding experience goes, I spent 6 months grinding in a fairly structured setting that was part of a 4 yr apprenticeship in toolmaking that was registered with the US Dept. of Labor. Also 4 years of schooling to go with it.

After I graduated, I did little grinding for quite a few years. Us toolmakers would make machine details and if they needed grinding, we had a dept. of journeyman grinder hands to do that. Somewhere in the 90's, we combined all of the machine trades into tool and diemaker and we did a lot more of our own grinding.

Around 12 years before I retired I broke some bones and came back to work on light duty for a while. I was re-assigned to our die room. The job included every type of grinding from OD on a nice old grinder with a digital and auto retract wheel to all types of surface grinding, ID grinding, lots of carbide. We seviced a bunch of carbide high speed stamping dies and a cold forming dept. Eventually there was an opening running a bryant ID grinder grinding cold former tooling. I started out grinding high speed steel dies with lots of forms dressed on the wheel by yours truly.

The real gravy was grinding carbide cold formikng dies. I did that for a year or so before I retired. Tolerance was +- .0002. We checked everything with plug gages because we could get a better feel than using an ID mic. Everything had to be polished to a microfinish of around 7 iirc. We usually did better than that. It is amazing when you are forming cold slugs of steel like play dough how much difference surface finish means. I had a full complement of comparators, profilometer, electrolimit gage, top shelf gage blocks and all associated grinding tooling. Mostly older equipment but well maintained and able to hold pretty good tolerances once you spent enough time on a particular machine to know the finer points of them.

I enjoyed grinding. Most of the guys that I trained with didn't want much to do with it. Too tedious and at least a few of them were scared of grinders, thinking any minute they would be eating a grinding wheel. I never had a problem with that. Just think before you act and it is pretty easy. After several years that is.

Brian

oldtiffie
12-23-2012, 07:19 PM
I am all in agreement with tdm.

What he seems to be doing is trying to get people to give concise accurate objective answers backed up by good information - to try and counter the plethora of subjective responses which all too often don't stand up to scrutiny.

Too many are "offended" or "thin-skinned" when questioned closely and/or being told something that they don't like.

Keep at it tdm.

lazlo
12-23-2012, 09:54 PM
Too tedious and at least a few of them were scared of grinders

Like a lot of guys here, I'm self-taught on the surface grinder: I bought one, read the Norton book, and screwed around with it. Ground a bunch of flat stuff with no problem: gibs, power hammer dies, bearing shims, the top of that prismatic scraping reference I hand scraped...

I wasn't scared until I was grinding a wrench flat on a hardened steel bushing. After several passes with no issue, the bushing rolled a couple of degrees in the V-block clamp. The wheel climbed up over the cylinder, and there was the sound of a gunshot: a 4" pie-slice chunk exploded out of the wheel. That was when I realized why the grit shield on the end of the SG was 1/4" thick :o

I'm a lot more careful after fixturing after that.

outback
12-23-2012, 11:22 PM
A surface grinder can do so many different things.

With this homemade attachment it can be a cylindrical grinder.

http://img.photobucket.com/albums/v30/jglass/Hardingknockoff.jpg

With a narrow cut-off wheel a surface grinder can be a cut-off machine. Many times I have used a cut-off wheel to notch out a
section of steel rather than mill away all the material. Often I end up with a useful reminant instead of a pile of chips.

http://img.photobucket.com/albums/v30/jglass/cutoff0004.jpg

A surface grinder can resharpen endmills.

http://img.photobucket.com/albums/v30/jglass/Shop%20Demonstrations/Endmill%20Sharpening/endmillsharpeing0005.jpg

Surface ground toolbits (http://img.photobucket.com/albums/v30/jglass/toolbits0002.jpg)

My experience, not all machinists like surface grinding. Myself, I'm quite fond of surface grinding.
Jim

oldtiffie
12-24-2012, 12:20 AM
Here is the OP:


I know this question will rank way up there as a Retardo Montalban question, but can someone explain to me exactly why surface grinders and surface grinding in general is so important? I see it discussed all the time and I see these really fancy, really expensive surface grinders in use at machine shops (in pictures, videos etc, not in person). But I never really understood why they are so important. If a surface needs to be ground, why not just mill it? Why not turn it on a lathe? Why not plane it down with a shaper? All I can think of is that grinding is appropriate (and necessary) if you're working with really hard metal that will damage or destroy conventional cutting bits made of tool steel. I can see where it would be necessary there. But heck, how often are you making a piece out of tungsten or something similar?

Another problem I see with grinding is that the grinder wheels are made of granulated stone that wears away as it grinds. I would think the wheel would get slightly smaller with every pass, complicating the matter of getting an even/parallel cut every time. Obviously it's a workable problem, but doesn't this complicate matters when grinding? Confused, and always have been about the whats, whys and wheres of surface grinding.

Underneath the possible "tongue in cheek" and a few basis errors the OP has some good questions.

Surface grinding generally is way over-hyped for no good reason other than "every body says so" - or does it or do they? - which leads on to the fallacy that "if all those peaople say its right then it must be right".

Perhaps so - perhaps not.

It is certainly no reason for anyone to think they really need a surface grinder even if they (only) "want one" (to be part of the "Club"?).

A surface grinder is ideal and perhaps the only available tool for some processes and surface finishes - but there are may where a non-surface-ground finish will quite surfice for an intended purpose - but not all.

Surface grinders do seem to get over-hyped similar to "air quills".

A lot of people who don't have a surface grinder seem to do pretty well without one as they plan their jobs occordingly.

There will be quite a few who have a surface grinder and hardly use it at all - and more likely a last resort than a first.

So the OP's questions are more then they might appear.

dp
12-24-2012, 03:31 AM
Being the irreverent bastid I am, I put a very well balanced grinding wheel onto one of my radial arm saws and what followed was the wrath of the narrow minded 'oh my gawd you can't expect 0.000000000000005" with that crap!. I actually got very nice finishes and within tolerance but not what you would get from a real surface grinder. Did I care? Oh hell no because I got the product I was after in spades. If you ignore the nimrods that chime in on this topic you can get very good results for your trouble. But if you call your radial arm saw grinder lashup a poor-man's surface grinder expect all hell to break loose from small drive-by minds that lurk here. Axe me how I know. All these experts who have actually never done it but are experts none the less - it is to laugh, ah hahahahahaha! There, I'm over it :) Never ever be afraid to tell them to stuff it if you get the results you like. It's not like you're making Boeing parts.

oldtiffie
12-24-2012, 04:21 AM
I well recall that little episode Dennis and to put it mildly the "carryings on" by some was not very edifying at all.

But at least you got the required end result using the tools and means required.

As needs must.

For some surfaces that just need a "clean-up" I often use the belt sander or the flap wheels in an angle grinder. You can do very well with a bit of practice.

I am all in favour of the methods (and reasons) why "Bush/Shade-tree Mechanics" and "Red-necks" do as they do. All too often all that is needed is a bit of a "touch up" (and a bit safer too).

If it works - it works and by definition its OK.

Just like your radial arm saw surface-grinder.

Mcgyver
12-24-2012, 08:44 AM
Being the irreverent bastid I am, I put a very well balanced grinding wheel onto one of my radial arm saws and what followed was the wrath of the narrow minded 'oh my gawd you can't expect 0.000000000000005" with that crap!. I actually got very nice finishes and within tolerance but not what you would get from a real surface grinder. Did I care? Oh hell no because I got the product I was after in spades. If you ignore the nimrods that chime in on this topic you can get very good results for your trouble. But if you call your radial arm saw grinder lashup a poor-man's surface grinder expect all hell to break loose from small drive-by minds that lurk here. Axe me how I know. All these experts who have actually never done it but are experts none the less - it is to laugh, ah hahahahahaha! There, I'm over it :) Never ever be afraid to tell them to stuff it if you get the results you like. It's not like you're making Boeing parts.

I don't know man, you don't sound over it......you need to write three more pages on what dirty scoundrels the nimrods are, then have a little ceremony where you burn the pages and forgive them :D :D

bborr01
12-24-2012, 09:26 AM
Here is the OP:



Underneath the possible "tongue in cheek" and a few basis errors the OP has some good questions.

Surface grinding generally is way over-hyped for no good reason other than "every body says so" - or does it or do they? - which leads on to the fallacy that "if all those peaople say its right then it must be right".

Perhaps so - perhaps not.

It is certainly no reason for anyone to think they really need a surface grinder even if they (only) "want one" (to be part of the "Club"?).

A surface grinder is ideal and perhaps the only available tool for some processes and surface finishes - but there are may where a non-surface-ground finish will quite surfice for an intended purpose - but not all.

Surface grinders do seem to get over-hyped similar to "air quills".

A lot of people who don't have a surface grinder seem to do pretty well without one as they plan their jobs occordingly.

There will be quite a few who have a surface grinder and hardly use it at all - and more likely a last resort than a first.

So the OP's questions are more then they might appear.

OT,

Some guys use their lathe for a mill and it works for them but I will not be selling any mills any time soon. A person can also use a flat stretch of sidewalk for a grinder. I prefer the proper tools for the job.

Brian

vpt
12-24-2012, 11:22 AM
OT,
A person can also use a flat stretch of sidewalk for a grinder.
Brian



You know, there have been times I almost tried! I don't remember what project I was working on but I needed something big ground down flat on one surface and the sidewalk crossed my mind. Not sure if it was wood I was working with at the time or what but I had the idea of using the truck, a rope, and a weight on top and pulling the whole deal down the sidewalk/road. lol

lazlo
12-24-2012, 11:49 AM
Being the irreverent bastid I am, I put a very well balanced grinding wheel onto one of my radial arm saws and what followed was the wrath of the narrow minded 'oh my gawd you can't expect 0.000000000000005" with that crap!. I actually got very nice finishes and within tolerance but not what you would get from a real surface grinder.

You can claim to be a hillbilly hero Dennis, but we've all asked you for pictures of the surface finish you got from hanging a SG wheel on a radial arm saw...

As an eminent poster on PracticalMachinist quipped: "that's the site where guys try to build surface grinders out of radial arm saws and toolpost grinders out of pencil sharpeners" :D

lakeside53
12-24-2012, 01:29 PM
Damn, I never thought of the pencil sharpener idea! ;) I have on occassion used draw-filing with pretty good results.


My new years resolution (still have 7 days to change my mind) is to get my surface grinder operational or toss it!

oldtiffie
12-24-2012, 10:05 PM
Originally Posted by dp

Being the irreverent bastid I am, I put a very well balanced grinding wheel onto one of my radial arm saws and what followed was the wrath of the narrow minded 'oh my gawd you can't expect 0.000000000000005" with that crap!. I actually got very nice finishes and within tolerance but not what you would get from a real surface grinder.

You can claim to be a hillbilly hero Dennis, but we've all asked you for pictures of the surface finish you got from hanging a SG wheel on a radial arm saw...

As an eminent poster on PracticalMachinist quipped: "that's the site where guys try to build surface grinders out of radial arm saws and toolpost grinders out of pencil sharpeners" :D

Keep going as you are Dennis - you are doing fine.

If the finish was as required then the means justified the end and the ends justified the means - what ever it was.

I quite liked the inventiveness and lateral thinking involved.

I avoid "surface" grinding if the job can get by without it - surface grinding is one of my last resorts - not one of my first resorts.

I avoid "too tight" tolerances - but they are OK if required for functionality - as that is the end requirement after all - and it is also what "Limits and Fit" aka "Tolerance"tables are for - same applies to surface finish/texture..

"Looks" or "show" rarely get a look-in here.

Some of the would be "purists" in many cases could not contemplate doing a "proper job" without a "proper" tool or machine. In many cases they are the smug self-opiniated tool and machine snobs who do tend to lecture (and hector) and look down upon those who they may see as lesser mortals or less "fortunate" - and by inference lesser machinists or not machinists at all.

I like the way you go about deciding what is needed for a job and what is availble to do it to suit the end need - ie functionality.

For the information of others:

A true "radial arm saw" (RAS) is a very rigid quite accurate bench-mounted very versatile machine - it is NOT a common mitre or bevel saw or docking saw - but it can be all of those things - and more besides.

RAS's are very often uses in Joineries and Cabinet-making shops and the like where high orders of accuracy and repeatability are required as matters of course.

http://www.justtools.com.au/prod1148.htm

http://woodworking.about.com/od/toolsequipment/p/RadialArm.htm

http://www.google.com.au/#hl=en&tbo=d&rlz=1R2IRFC_enAU360&sclient=psy-ab&q=radial+arm+saw&oq=radial+ar&gs_l=hp.1.1.0l4.0.0.1.1683.0.0.0.0.0.0.0.0..0.0.le s%3B..0.0...1c.HqIuSVanKEs&pbx=1&rlz=1R2IRFC_enAU360&bav=on.2,or.r_gc.r_pw.r_qf.&bvm=bv.1355534169,d.dGY&fp=def9f3f538eb70d&bpcl=40096503&biw=1920&bih=846

Spin Doctor
12-25-2012, 10:21 AM
Yes the average HSM can get by just fine with out a surface grinder. But where a surface grinder really shines is in the production of special fixtures and tooling to be used on other machines and in the fitting of parts in assemblies. If precision is a function of the quality of your work holding then you need to produce fixtures* that are an order of magnitude greater than than the tolerances you are shooting for. Yes other factors enter in but lets say your interest is building small radial engines. In that instance your are going to need good fixturing to produce the parts with repeatability. Look at the difference between good fixtures and adequate ones as the difference between a highly accurate collet set up and a 3 jaw chuck**


* Even a shop made parallel or angle block is a fixture.
** Why is a boat anchor superior to a Three Jaw Chuck? The anchor at leasr has a place to attach a rope. :p

Machine
12-27-2012, 09:31 PM
Thanks for all the great responses everyone. I don't even have a mill yet and now I'm thinking I should get a grinder first. :) I love the finish a grinder gives to a finished part. All the better it can be built to such high tolerances, even if it's not necessary. Out of curiosity though, since precision grinding and hand scraping have both been used to finish beds and ways on machine tools, can a machined part be finished to high precision by hand scraping instead of grinding?? I've always been fascinated by hand scraping and have often thought of learning the process. I assume it's a PITA to learn though.

mike4
12-28-2012, 12:51 AM
I couldnt agree more with your statement , some even come across as though they started a reply before even reading what was originally posted.

I have stated what was done or or how something was set up and a lot of suggestions came suitable for someone who had no idea of how to do anything .

The people concerned can do some very good work and the results look spectacular in some cases , however in a working for money situation I would like to know how many could get the job done with what is available , either materials or equipment .
Also can they work in a hot dirty enviroment covered in crap from the machine they are repairing>?
Some of us do that on a daily basis , to earn a living and dont bother with frivolities like photos or writeups , as in a lot of cases your camera and phone is left with security at the gate when you drive in .
You are there to get the job done safely and in a timely manner , as neat as possible or sometimes make it look like it was never touched (paint and weld patterns ,surfaces level)

Michael

Weston Bye
12-28-2012, 07:09 AM
The place where I work calls upon me to build test fixtures on a regular basis. They also purchase fixtures from outside sources. My fixtures work well for the intended purpose, but are rather plain and utilitarian. The fixtures purchased from other sources all have ground surfaces - even the inconsequential ones - and are beautifully black oxided. In general, the purchase fixtures are difficult to use, or don't perform the measurement or other function exactly as intended and are costly - but they are pretty.

I get no respect for my fixtures, even while they are being used to efficiently process thousands of parts a day.

I could take the extra time to grind the surfaces, but would then get complaints about what is taking so long.

p

oldtiffie
12-28-2012, 07:24 AM
Here is the OP:


I know this question will rank way up there as a Retardo Montalban question, but can someone explain to me exactly why surface grinders and surface grinding in general is so important? I see it discussed all the time and I see these really fancy, really expensive surface grinders in use at machine shops (in pictures, videos etc, not in person). But I never really understood why they are so important. If a surface needs to be ground, why not just mill it? Why not turn it on a lathe? Why not plane it down with a shaper? All I can think of is that grinding is appropriate (and necessary) if you're working with really hard metal that will damage or destroy conventional cutting bits made of tool steel. I can see where it would be necessary there. But heck, how often are you making a piece out of tungsten or something similar?

Another problem I see with grinding is that the grinder wheels are made of granulated stone that wears away as it grinds. I would think the wheel would get slightly smaller with every pass, complicating the matter of getting an even/parallel cut every time. Obviously it's a workable problem, but doesn't this complicate matters when grinding? Confused, and always have been about the whats, whys and wheres of surface grinding.

I can only presume that he means what he says in a HSM-er context and not that of a commercial shop or enterprise.

Can we keep it that way as I often see members here who are thinking of buying or who have just bought a surface grinder?

mike4
12-28-2012, 07:36 AM
No problem with that , I'll just read from now on , maybe go back to "lurking " some would put it .
Michael

Jaakko Fagerlund
12-28-2012, 07:39 AM
I could take the extra time to grind the surfaces, but would then get complaints about what is taking so long.
It is a pity that it always goes like this, though I try to do my best to make jigs that are nice looking, efficient and in timely manner, but always it is not possible.

It is just so much more professional and neat when black oxidised and the relevant working surfaces then milled/ground/turned. One can immediately see what the important surfaces in the jig/tool are and also easier to keep it clean as you see what parts do need cleaning and what not.

Weston Bye
12-28-2012, 08:18 AM
.......
I can only presume that he means what he says in a HSM-er context and not that of a commercial shop or enterprise.

Can we keep it that way as I often see members here who are thinking of buying or who have just bought a surface grinder?

Many of us have related our "commercial" experiences with surface grinding because that is the only exposure we have had to grinding. Though not "home shop" the experience still applies.

The thing is, most home shop projects don't require the precision of grinding. The grinder, judiciously used, can improve the appearance of the home shop project, bringing a comensurate level of pride to the finished product. When the home shop begins to morph into a hobby business, the occasional grinding requirement may crop up.

I have gotten along for 20-odd years without a surface grinder in my home shop. That doesn't mean that I wouldn't jump at the chance to get one if it could be had at a reasonable cost, or even a little more.

If I had a grinder, I would use it: Give a kid a hammer, and all the world looks like a nail.

As a writer of construction project articles, I am interested in reproducible results. Designed-in requirements for ground surfaces would be a show-stopper for most of my readers. I would have to restrain myself.

Lu47Dan
12-28-2012, 11:18 PM
I have a Boyer-Schultz 612 surface grinder in my shop, I use it to sharpen my chipper/shredder blades, make parallels, and to remove small amounts of material to finish fit two parts together. A surface grinder is not a "necessary" home shop machine but it handy to have one when you need it.
Dan.

oldtiffie
12-29-2012, 06:09 AM
This relates to a small all-hobby (non-commercial) "HSMer's" shop.

A surface grinder - with a bit of ingenuity - and perhaps a good "Spindexer" - can get very close to being a tool & cutter grinder which may justify the cost and space for getting a small surface grinder and perhaps delay or negate the reasons for the expense and space of a tool and cutter grinder. It would go close to not needing a "Blador" either.

Add one of these (can't remember the name but Shars has them) and a "saucer" grinding wheel and away you go.

http://i200.photobucket.com/albums/aa294/oldtiffie/Grinder_work-head_demo/Grind_work-head_demo3.jpg

Add your trusty "Spindexer" as well as a magnetic chuck (tilting type is best but a non-tilting one is quite satisfactory), perhaps and angle plate and your small surface grinder (no need for it to be big - a manual one is quite sufficient) and your surface grinder if you have one has its capabilities expanded quite a bit.

If you don't have a surface grinder, it might justify buying a small manual feed surface grinder too.

Who knows.

PixMan
12-29-2012, 06:07 PM
Here's an example of what a good surface grinder can do for even a home shop guy. The CA-400 size QCTP tool holder blocks I'd bought from Tools4Cheap.net (http://www.tools4cheap.net) needed 3mm milled off the bottom to be able to get a 1" shank insert holder to drop to the lathe's centerline. I used a 45º 4-insert Widia milling cutter to rough them out, but being so very hard the inserts would just rub on a shallow finish cut (or ruin a flycutter.)

http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/IMG_1393-r.jpg

I didn't take any photos of that particular holder after I ground it to a nice finish, so here's some smaller AXA-100 size ones that I milled and finish ground for a fellow who need the same alteration to his. I used a Norton 32A60-IVBE 8x1x1-1/4 wheel to take off the last .002".

http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/DSC_0164-r.jpg

He seemed very happy with his shiny holders!

Machine
12-29-2012, 08:56 PM
Wow, that's impeccable work pixman. I never should have asked for information about the grinder. Now I'm looking for one of them before I even own a mill.

lane
12-29-2012, 09:55 PM
Yes that ground finish looks good but for all practical purpose is not needed . The mill surface would do the job just as well.
Yes I also have a nice surface grinder in my home non commercial shop. Had it for years but hardly ever use it. No real need . Also I may add it is fully tooled about 50 different grits and grades of grinding wheels and gust about every tool you could use are need on a surface grinder . But most of the time it sits . The mill and lathe are used all the mine . So if you are thinking about buying some machines get a lathe and mill first .The rest will come later. And no I am not new to all this 48 years in machine shops plus 35 years as a Home shop guy . So go from their.

PixMan
12-29-2012, 10:17 PM
I do agree that the ground finish isn't required for that application, I just wanted to deliver the highest quality product I could achieve. And I did. I try to adhere to the Cub Scout motto that was drilled into me at 7 years of age..."Do Your Best!"

If interested I am willing to post a couple of photos of the surface grinder I got for my dad's shop. I earned it in exchange for a 1/2 day of training a shop owner and one of his employees on how to run a Citizen CNC screw machine he had in his shop. While it only cost me $271 to rent a truck with a lift gate and bring it home, I've since spent more than twice that to tool it up and add a complete OE coolant/dust collector system and its associated sheet metal guards. I'm now just over an $1100 investment to be able to grind a great many little parts. It's a 1981 Kent KGS-200, a 6x14 manual machine, no DRO. I run it off a RPC to have 3-phase power to the 2HP spindle motor and the coolant/dust collector system.

I've only added 12 or 13 wheel adapters and wheels as of now. The machine accepts wheels of up to 8" diameter x 1" wide and they're a little harder to find in a good deal. I want to stick with the 8" to keep the cutting speed up. With the 2HP motor and a Norton 5SG (seeeded gel) wheel, it can really remove a lot of stock in a big hurry when I want to!

lazlo
12-29-2012, 10:42 PM
Here's an example of what a good surface grinder can do for even a home shop guy.
...
He seemed very happy with his shiny holders!

Very nice work!

oldtiffie
12-29-2012, 11:41 PM
Yes that ground finish looks good but for all practical purpose is not needed . The mill surface would do the job just as well.
Yes I also have a nice surface grinder in my home non commercial shop. Had it for years but hardly ever use it. No real need . Also I may add it is fully tooled about 50 different grits and grades of grinding wheels and gust about every tool you could use are need on a surface grinder . But most of the time it sits . The mill and lathe are used all the mine . So if you are thinking about buying some machines get a lathe and mill first .The rest will come later. And no I am not new to all this 48 years in machine shops plus 35 years as a Home shop guy . So go from their.

I agree with Lane.

"Looks" and "finish" more than functionally required doesn't happen here either but having said that given that Pixman finished the job for "looks" ("accuracy" was not mentioned or a requirement either it seems) it turned out very well.

If it were me, and if I thought it needed a bot of "dressing up" I'd have use the top (supported) face of my belt sander or the sanding disk - both on my pedestal grinder.

http://i200.photobucket.com/albums/aa294/oldtiffie/Belt_sander/Belt_sander3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Belt_sander/Belt_sander1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Belt_sander/Belt_sander2.jpg

I often use the side or front of the "gray emery" (shop all-purpose) wheel as well.

Replacing a belt or disc is only a matter of a minute or so to do.

PixMan
12-30-2012, 08:42 AM
Get some woven abrasives for that grinder, oldtiffie, and you'll really see some nice finishes. By that I mean products such as 3M's Scotchbrite or Norton Beartex.

Mcgyver
12-30-2012, 11:01 AM
Yes that ground finish looks good but for all practical purpose is not needed . The mill surface would do the job just as well.

agreed. There a times though when ascetics on the finished product are important/desirable.

probably the most use to which I've put mine is its intended purpose; making tools. I made stuff from hot rolled, have it professionally deep casehardened then precision grind it, I've had rusted hardened tooling come in the door that's be put back to how it should be, I've taken other hardened tooling I was not sure about made it perfect - either blocks, angle plates etc or tooling for machines such as this http://bbs.homeshopmachinist.net/threads/53212-A-better-vise-than-the-Kurt?.

There is no homogenous definition of what a home shop needs or does. Having a SG makes things easier and increases your potential....same as a mill (is a mill 'needed' if you have a file?). I agree it will see a fraction of the use a mill will, but otoh need isn't what this is about.

For me, I've enjoyed increasing my abilities - knowledge as well as shop capabilities. That's a different 'need' than someone who say wants to make a steam engine. Unlike a commercial shop where need is economically defined, need is basically psychological (we're doing this because we want to) so it's kind of wrong for one take what they decided they need and think it applies it to the next guy.

bborr01
12-30-2012, 11:28 AM
I sure would not make a surface grinder my first piece of machinery. Mill or lathe first, drill press, snag grinder, welder, torch next. Surface grinder would be quite a ways down the list, but that doesn't make them not needed.

I have been in a lot of tool and die shops and job shops and have never seen one that didn't have a surface grinder. That should tell you something.

Brian

Jaakko Fagerlund
12-30-2012, 11:53 AM
I have been in a lot of tool and die shops and job shops and have never seen one that didn't have a surface grinder. That should tell you something.
Yes, it tells me that the shops you have visited have done, are doing or see them dfoing in the future jobs that require a surface grinder or ground surface.

I've been to a three tool & die shops that did not have a surface grinder and they are doing just fine as such. The thing, the work they do do not require one.

Point being, the shops have the tools they need or see need for.

oldtiffie
12-30-2012, 03:43 PM
Get some woven abrasives for that grinder, oldtiffie, and you'll really see some nice finishes. By that I mean products such as 3M's Scotchbrite or Norton Beartex.

Thanks Pixman - appreciated.

I just photographed the grinder with the belt/s on for the previous job - several years ago I think.

I do have - and use - the Norton/3M belts you nominated - I keep a good range of belts for that grinder as it gets a lot of use.

The right belt/s will clean up "hot-rolled" and some others quite well.

The right belts for the job will either really rip off stuff (welds and cast surfaces included) or give a very nice finish that is aesthetically pleasing as well.

I often use the front/curved nose of the belt for finishing lathe tools etc. - with the cutting edge facing down - as the belt runs cooler than the wheel and it leave a nice hollow grind with the very fine "burr" (to be hand-honed) at the bottom. The belt is inclined to "round over" the edge if ground with the edge at the top.

I generally hand grind my lathe tools (on that gray/aluminium oxide wheel) and hand-hone them (I grind the"hollow" on the front of thegray wheel too).

Hollow ground tools are very easy to "touch up" with a diamond hone while still in the lathe or just remove them at the lathe, hone and replace in the lathe.

If I need to measure an angle I use a good protractor or angle gauge.

I rarely use a T&C grinder (or an adapted surface grinder) for lathe tools - all by hand.

I also hand-grind my drills.

The belt/wheels are ideal for removing post-machining burrs as well.

Belt-grinding a radius on the corner of a job is quite easy as well.

I stick to manual skills as a first priority - manual grinding included - machine grinding is a last resort that is used if and when required - which is not very often at all.

But back to topic, I have a fair range of machine grinders - surface grinder included - but they get little use - but they do get used if needed.

End mills say 3/8" or less get "binned" when they are blunt as sharpening them is awkward and the cost is not too high and is as much a "consumables" item as lathe tools and welding rods are. I do bin 1/2" cutters as well on occasion for the same reason.

Machine
12-30-2012, 05:49 PM
Interesting. So even when grinding's super precision isn't needed or really warranted, there's still the aesthetic value of a truly professional looking job that can be provided by a finely ground surface. And this can be achieved with an ordinary belt sander equipped with the right grit paper (as shown in oldtiffie's pics)? Awesome, I need an ordinary grinder anyway, so I'll try and pick one up like old tiffie's, although I haven't seen one quite like that here in the states (usually only see belt sanders in wood shops). Oldtiffie is that an Oz sander or what?

oldtiffie
12-30-2012, 06:39 PM
Thanks Machine.

That Abbott and Ashby grinder and sanding belt and disk machine is Australian-made but I guess that variations of it wil be available else-where.

I don't worry too much about a "finely ground" surface as a good coarse one suits my needs. But having said that I can get a very good finish just by "easing off" with a finer belt/disk or use a partially-worn (or even very worn) belt.

Belt life can be extended if the belt gets "clogged" by using a very simple cheap "stick":

http://www.machineryhouse.com.au/G183

See the linked page for a listing of comprehensive belts and discs available (the range is bigger than this elsewhere):

http://www.machineryhouse.com.au/G156

I also use these a lot - angle grinder with flat or "vented" disk and "flap wheels" as they do very well for me. A bit of skill is needed as is care but its not dificult at all and the finish is not too bad either.

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift4.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift5.jpg

I can see the point of grinding with the "scalloped" wheels and they do seem to work/run cooler. I saw them a while ago at one of my BOC dealers and bought quite a few 4" and 5" wheels. I went back later after seeing how well they worked but there was only a couple left - which - I bought - and the Dealer said they were not renewing stock as it was a "slow mover" and most shops used the full circle disks. Well it was nice while it lasted.

"Flap" wheels are very versatile and work quite well though they do wear quickly and can seem a bit expensive. They are ideal for a better/"softer"/smoother finish.

All discs will lease a "swirl" or partial-circle finish - some coarser/finer than other but it does the job and works well for me.

bborr01
12-30-2012, 08:20 PM
Yes, it tells me that the shops you have visited have done, are doing or see them dfoing in the future jobs that require a surface grinder or ground surface.

I've been to a three tool & die shops that did not have a surface grinder and they are doing just fine as such. The thing, the work they do do not require one.

Point being, the shops have the tools they need or see need for.

What do these shops do when they have something that is Rc60-62 and has a heat treat finish. Send it out to someone with a surface grinder? What do you do when you have a piece of carbide silver soldered to a piece of tooling and it needs to be precision tooling. My guess is that your shops send this work out or just pass on the job.

I suppose that a person can run a shop with no equipment at all. Farm everything out and not be bothered with making anything.

Shapers have become fairly obsolete. Surface grinders not so much. How many surface grinder ad's are there in catalogs. Lots of them. Shapers, none that I have seen lately. Yet lots of home machinists think shapers are almost indispensable. Persanally, I wouldn't trade my little Harig Super 612 for a whole row of shapers.

There seems to be a mis-conception among a lot of home shop machinists that surface grinding is just about making things shine. Nothing could be further from the truth. Surface grinders are about being able to precision fit details of almost any hardness and keep them square and parallel. Those who don't ever learn about the tasks that a surface grinder can perform are missing out on a lot about the metal working trades.

Brian

lazlo
12-30-2012, 09:02 PM
http://youtu.be/9pe0rNieL-Q?t=5s

John Stevenson
12-30-2012, 09:20 PM
Jaakko,
Are you related to Nick Mueller or are you upstream from him because I reckon there is something in the water.

bborr01
12-30-2012, 11:22 PM
http://youtu.be/9pe0rNieL-Q?t=5s

Lazlo,

I am just trying to make sure that nobody here reads this thread and thinks that a belt sander or a radial arm saw is a suitable replacement for a surface grinder. Also, I am surprised at some here that think that they are. The world has enough misinformation without us adding to it here.

Brian

MichaelP
12-30-2012, 11:40 PM
Also, I am surprised at some here that think that they are. For those who sharpen endmills manually on a bench grinder, they are. :)

oldtiffie
12-30-2012, 11:56 PM
Lane made the point earlier that in many cases a machined-only finish will suffice where looks or utility are all that is required - I agree with that. Improve the machined fines and a lot of the "dressing-up" on a surface grinder will disappear.

Machining to or within 0.001" is quite normal on normal work-shop machines (lathe mill etc.) with no further grinding required.

Ther are many here who surface grind to "tenths" where it is not needed in terms or practicality but often too much "just for looks" (or just because they can?) when it isn't needed either.

The reasons or "need" for a cylindrical grinder (not just a tool-post grinder on a lathe) have similar "justifications" when a reasonable lathe (and perhaps a file and "wet and dry" cutting paper) can do quite well.

A close look at any table or limits and fits will soon show that the difference between limits is mosly 0.001" (~ 0.025 mm) or over/wider - very few are to limits of 0.0001 or perhaps 0.0003".



I'd be the first to say that if a job was hard and needed to be machined very accurately, that grinding is a very good - but not the only - option.

But grinding just for the sake of it is hard to justify - the more so if its to perhaps unnecessarily just to use the machine because you have one.

My guess is that many who have a surface (or cylindrical) grinder either use it infrequently or perhaps not at all but they still "get by" very well.

gcude
12-30-2012, 11:58 PM
Lazlo,

I am just trying to make sure that nobody here reads this thread and thinks that a belt sander or a radial arm saw is a suitable replacement for a surface grinder. Also, I am surprised at some here that think that they are. The world has enough misinformation without us adding to it here.

Brian

I'm almost surprised nobody has suggested a flap wheel in a cordless drill. :rolleyes:

Juergenwt
12-31-2012, 12:00 AM
tdmidget - quoted from above.:"I have run several machine with .00001 graduations and new machines are even more capable."
That is good. Very good! Are you sure it's not .0001? .00001 is laboratory work and there could be some machines out there. I have never seen one. You are looking at gage block quality. I am sure those are made on some very special machines and I don't know if they are Grinders.
Lapping would be more likely. Can anybody comment on this?

Mcgyver
12-31-2012, 12:05 AM
I am just trying to make sure that nobody here reads this thread and thinks that a belt sander or a radial arm saw is a suitable replacement for a surface grinder. Also, I am surprised at some here that think that they are. The world has enough misinformation without us adding to it here.


your finger is in the dyke, but alas its a chain link fence. Those who rely on unqualified internet info as their sole source are already lost ....but I doubt any any (many?) here think either is a substitue

oldtiffie
12-31-2012, 12:15 AM
I'm almost surprised nobody has suggested a flap wheel in a cordless drill. :rolleyes:

Good point.

I was going to make it earlier but over-looked it.

A good wire cup or wheel in a good angle grinder works very well when suited to thejob. The finish wil lbe more "burnished" than cut but it will be cut never the less.

Smaller brushes work very well with a good die-grinder.

I gave away using battery-powered drills for wire long ago - especially for "cups" - as they are hard to control.

Toolguy
12-31-2012, 12:20 AM
There are a few CNC grinders that can hold a few millionths, the new micro mills and lathes can, these are the ones that can use down to a .001 end mill and not snap it off. The higher grade gage blocks are lapped to a few millionths too. All the grinders I've ever used were only marked off to a tenth. When you get down to it, holding a tenth or 2 is pretty fine work. I can do it if I have to, but it's a lot more fiddly than 1 or 2 thou.
I use my surface grinder fairly often, usually because that's the fastest easiest way to get where I'm going. With a little care, half a thou. is pretty easy to hit grinding.
A lot of things + or - .002 is quite good enough and doable at a fairly good rate on the mill or lathe.

bborr01
12-31-2012, 12:37 AM
tdmidget - quoted from above.:"I have run several machine with .00001 graduations and new machines are even more capable."
That is good. Very good! Are you sure it's not .0001? .00001 is laboratory work and there could be some machines out there. I have never seen one. You are looking at gage block quality. I am sure those are made on some very special machines and I don't know if they are Grinders.
Lapping would be more likely. Can anybody comment on this?

Sure, I will go for the bait. .00001 is 10 millionths. A tenth of a tenth. You can change the size of most pieces a tenth or so just by holding it in your hand for a while or running it under a drinking fountain. Holding tolerances of a tenth is very difficult. Maybe with a brand new grinder that is all warmed up on a good day. Most people can't even accurately measure a tenth with a micrometer. Give 5 experienced journeymen the same piece and ask them to give you the exact size with their micrometer and you will probably get 2 or 3 different answers. Then go check the part against top shelf gage blocks using an electrolimit gage and probably find that only 1 or 2 will get it right, if any.

When I was working, we had a gage department. The guys that worked in there were the most capable I have seen at holding tight tolerances. When they needed to hold these kinds of tolerances they usually ground to get the proper geometry and lapped into final size.

The joke among the grinder hands was that when an engineer would come in and ask to have a couple of tenths taken off from something was that engineers go camping in tenths.

BTW, none of what I just wrote applies to tdmidget. He the man. He can probably grind in billionths. As in 1.38857338. With his eyes closed and one hand tied behind his back. Superpowers, I tell ya.

Brian

Jaakko Fagerlund
12-31-2012, 06:23 AM
What do these shops do when they have something that is Rc60-62 and has a heat treat finish. Send it out to someone with a surface grinder? What do you do when you have a piece of carbide silver soldered to a piece of tooling and it needs to be precision tooling. My guess is that your shops send this work out or just pass on the job.
They don't do it, as their jobs don't handle hardened work pieces (unless you count hardened aluminum, copper and stainless). Yes, it is a tool & die shop, but there are still tools & dies that don't need one single piece of hardened steel in their construction. They have specialised in certain tools/dies/jobs and those won't require a surface grinder. (wire) EDM at the most, but no SG.

The point I'm trying to make is that one can't generalise based on assumptions.

John, not related, but Finland seems to be upstream from Germany...maybe I have pissed in my own cereals and dumped it then to the river :D

darryl
12-31-2012, 09:45 AM
Don't have a S/G, but I do have a disc/belt sander :) With care you can remove machining marks without rounding off corners and edges, and you can remove high spots and warps in many cases. I haven't been to the point yet where I needed a S/G. One is not a substitute for the other, but it is the belt sander that I couldn't do without.

MrFluffy
12-31-2012, 09:46 AM
Lets extrapolate this to the extreme. Nothing in our shop's is essential unless your making a living in there. I could just pay a jobshop to build my parts and it would cost me far less in money than I have invested in tools and equipment, and far far less in time. Just email them a .dwg of what I want and bing it turns up in the mail a few days later. And I know people who build bikes and projects like that too.

But then, the reasons I'm in the shop can't be measured solely in pounds shilling and pence. I do it for the zen of it if you like. And I'm pretty sure the shop is basic escapism for other people to get their zen away from the mrs etc time too.
And as time goes on, I find I have the basic equipments, and I want to go to the next level. I got the same argument when I bought a dedicated cylinder boring bar, wont use it enough to pay for itself, waste of space etc etc. But its saved my neck and its purchase price on one particularly awkward job of late and I use it in ways I didn't imagine when I was hunting one down. Ive just finished cleaning the surface grinder in the gloat thread, and Ill hook it up to power tonight and get to know it. And I'm sure again, it will save me more than its purchase price, and what is more important, mean I don't have to send some awkward hard piece out for grinding with all the associated delays, the being put the back of the queue while more profitable industrial jobs come in and take priority over my tea + biscuit money jobs etc. And I have a big pile of 2" end mills waiting that are most certainly not in the disposable class that Ive bought and had go blunt over the years, and some angle plates etc I got given because theyre bruised and need to true up. So I'll be sparking my way through them also.
And what next? as the saying goes, when you get there, theres no there. Unless you don't want to progress.

vpt
12-31-2012, 09:47 AM
So no one wants to buy my BP surface grinder yet? :) I'll take a 9x40+ mill in trade.

bborr01
12-31-2012, 11:26 AM
They don't do it, as their jobs don't handle hardened work pieces (unless you count hardened aluminum, copper and stainless). Yes, it is a tool & die shop, but there are still tools & dies that don't need one single piece of hardened steel in their construction. They have specialised in certain tools/dies/jobs and those won't require a surface grinder. (wire) EDM at the most, but no SG.

The point I'm trying to make is that one can't generalise based on assumptions.

John, not related, but Finland seems to be upstream from Germany...maybe I have pissed in my own cereals and dumped it then to the river :D

Jaakko,

I am starting to question your story. You stated earlier that there were 3 shops that you have been in that didn't have surface grinders. Then in your last post you post that "it is a tool and die shop". Singular, not plural. I am well aware that wire edm's are used in die making a lot. But how do you get the die steel flat and sharp before you burn it? What kind of material are they forming, paper? You said hardened aluminum, copper and stainless. They form hardened stainless with soft die steels. Really? As I stated earlier, you can buy lots of tooling that is pre ground. Someone else is surface grinding it for you.

If you went to a die shop and told the foreman that you don't need a surface grinder because you can get it shiny enough with a belt sander, you would be laughed out of the shop post haste. The diemakers would still be telling that story years later, while laughing their heads off.

Brian

tdmidget
12-31-2012, 12:15 PM
tdmidget - quoted from above.:"I have run several machine with .00001 graduations and new machines are even more capable."
That is good. Very good! Are you sure it's not .0001? .00001 is laboratory work and there could be some machines out there. I have never seen one. You are looking at gage block quality. I am sure those are made on some very special machines and I don't know if they are Grinders.
Lapping would be more likely. Can anybody comment on this?

Royal Master centerless grinders and Studer cylindricals can be had with these graduations. I have also seen an older Taft Pierce surface grinder with .00002 graduations.
Gage blocks are lapped to millionths in the single digits.

Mcgyver
12-31-2012, 12:54 PM
What kind of material are they forming, paper? You said hardened aluminum, copper and stainless. They form hardened stainless with soft die steels. .



how did you get that? I thought his post quite clearly said the dies are of hardened AL, copper and stainless, not what material the dies are used on. ???

bborr01
12-31-2012, 01:34 PM
how did you get that? I thought his post quite clearly said the dies are of hardened AL, copper and stainless, not what material the dies are used on. ???

I would read "workpiece" to mean the material being formed.

Brian

bborr01
12-31-2012, 01:51 PM
Post deleted.

charlie gary
12-31-2012, 06:26 PM
Here's something no one has mentioned, yet. Grinding doesn't cause work hardening like milling or turning can.

oldtiffie
12-31-2012, 08:55 PM
Almost certainly true but grinding can cause over-heating with resultant distortion (many materials) and micro-cracks (hardend material mostly).

bborr01
01-01-2013, 01:01 AM
Almost certainly true but grinding can cause over-heating with resultant distortion (many materials) and micro-cracks (hardend material mostly).

Not when done properly.

Brian

Jaakko Fagerlund
01-01-2013, 06:59 AM
Jaakko,

I am starting to question your story. You stated earlier that there were 3 shops that you have been in that didn't have surface grinders. Then in your last post you post that "it is a tool and die shop". Singular, not plural. I am well aware that wire edm's are used in die making a lot. But how do you get the die steel flat and sharp before you burn it? What kind of material are they forming, paper? You said hardened aluminum, copper and stainless. They form hardened stainless with soft die steels. Really? As I stated earlier, you can buy lots of tooling that is pre ground. Someone else is surface grinding it for you.

If you went to a die shop and told the foreman that you don't need a surface grinder because you can get it shiny enough with a belt sander, you would be laughed out of the shop post haste. The diemakers would still be telling that story years later, while laughing their heads off.

Brian
Sorry if you feel that way from my mistake in typing or the fact that I said I've visited 3 of such shops and then talk about one shops work.

I don't know how much tool & die work you have done or seen done, but for example most of the jigs and aluminum pour casting (don't know the proper english term for them) dies are not hardened at all. And there is no reason for them to acquire a surface grinder, as the parts they buy as ready made components (standards mold parts) are already milled or ground flat.

If you went to those places and told them they need a surface grinder you would have to be a hell of a salesman (think of selling sand to a desert) to get it sold. No need for grinder, the work they do don't need a grinder and I'm quite sure they even would not have a place for a grinder. So, why would they buy a grinder to that tool & die shop.

bborr01
01-01-2013, 11:00 AM
Sorry if you feel that way from my mistake in typing or the fact that I said I've visited 3 of such shops and then talk about one shops work.

I don't know how much tool & die work you have done or seen done, but for example most of the jigs and aluminum pour casting (don't know the proper english term for them) dies are not hardened at all. And there is no reason for them to acquire a surface grinder, as the parts they buy as ready made components (standards mold parts) are already milled or ground flat.

If you went to those places and told them they need a surface grinder you would have to be a hell of a salesman (think of selling sand to a desert) to get it sold. No need for grinder, the work they do don't need a grinder and I'm quite sure they even would not have a place for a grinder. So, why would they buy a grinder to that tool & die shop.

Jaakko,

I think the difference is in terms that are used in your country versus mine. What you are describing is a die cast die shop, or mold shop here. I equate tool and die shop to mean steel stamping. Many years ago I worked in a paper box making plant and they had a "die shop" for making steel rule dies. No surface grinder there either. But then that was not a "tool and die" shop.

Brian

Mcgyver
01-01-2013, 11:10 AM
I equate tool and die shop to mean steel stamping.

Thats what i wondered earlier and why i questioned your response...could it be you're taking your particular experience and conlcuding thats how the world is? All kinds of tool and die work is done in say Aluminum and other soft materials. For sure we would call it a Tool and Die where we'd say have a plastic injection mold made and the men working there would be tool and die makers. Is this not the case in the US?

bborr01
01-01-2013, 12:08 PM
Thats what i wondered earlier and why i questioned your response...could it be you're taking your particular experience and conlcuding thats how the world is? All kinds of tool and die work is done in say Aluminum and other soft materials. For sure we would call it a Tool and Die where we'd say have a plastic injection mold made and the men working there would be tool and die makers. Is this not the case in the US?

I spent about 10 years as a member of an apprentice committee that consisted of 2 union members and 2 mgt. members. We worked with the local community college and the US Dept. of Labor to see to it that our many apprentices got well rounded training. As I recall, there was a distinction between tool and diemaker and diecast diemaker/moldmaker. The trades are somewhat similar but different enough that a mold maker could not be expected to do tool and diemaker work and vice versa. They are two very different trades.

Brian

Jaakko Fagerlund
01-02-2013, 12:56 AM
Ah, that might explain things the, as the trade is called 'tool maker' here, but in reality covers tools, dies, molds, all the related things.

Sorry for the confusion.