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RGKing
02-04-2003, 11:45 PM
Does anyone recall an article in HSM or Machinists Workshop from around 1996 or later, regarding building a surface grinder from a belt sander? Maybe I saw it some place else but I pretty sure it was in one of these magazines. Thanks

Spin Doctor
02-04-2003, 11:48 PM
I'll have to pull the hard copies out of the basement but I think it was further back, maybe around 92 or 93

RGKing
02-04-2003, 11:56 PM
Thanks for the reply. I specified 1996 only because I started subscribing to the magazines that year. I wasn't familiar with them before that time.

Uncle Dunc
02-05-2003, 03:12 PM
Doesn't ring a bell, which doesn't mean it's not in there. http://bbs.homeshopmachinist.net//smile.gif

The only homemade surface grinder I remember seeing was in one of Guy Lautard's TMBR books. The guy had mounted a vertical post on a granite surface plate with a vertical adjustment for a normal grinder spindle. I don't remember if it was direct drive or belt drive like a toolpost grinder. Then he just moved the work under the wheel by hand, taking very light cuts and remembering not to feed it the hungry way.

It would work real well for my needs, and I'm sure I'll get one built one of these days. http://bbs.homeshopmachinist.net//smile.gif I'm still stuck in the design phase, trying to figure out an easy way to eliminate all the backlash in the vertical adjustment screw so I can get accurate and positive down feed in tenths.

omefford
02-05-2003, 04:17 PM
I believe the article you are refering to in HSM uses a radial arm saw as the basis of the surface grinder by replacing the blade with a wheel. If I remember correctly it looked like a disaster waiting to happen.

wierdscience
02-05-2003, 11:21 PM
I remember a tool grinder in Projects in Metal that had that as an option.

Rustybolt
02-05-2003, 11:45 PM
There was an artical in "Model Engineering Workshop" where a guy took a bench grinder and mounted it vertically. He turned it into a kind of swing grinder. I forget what he used for fine feed, but he didn't recomend grinding more than half a thou. at a time.

Time passes.................................

Found it. MEW No. 45 October november 1997

darryl
02-06-2003, 04:13 AM
I once asked someone in the abrasives industry about building a surface grinder myself, and he asked me how rigid the setup would be. Since then, I have built the device, (using steel plate ) and found that it isn't rigid enough. The finish produced varies a lot, depending on the particular vibrations induced by the grinder, the workpiece, and other factors. No way would I expect a good result from a converted radial arm saw. I think you could get a more accurate surface by milling, unless you build very solidly.

Forrest Addy
02-06-2003, 05:09 AM
A surface grinder fitting the traditional definition is a damn accurate and sophisticated piece of equipment.

Just because some home-made lash-up makes sparks and may make stuff sort of flat doesn't make it a surface grinder any more than a kid in a cape riding down the garage roof on a bicycle is going to "up! up! and awaaay!" DAMHIKT

The machinist trade is a discipline driven by the need for accurately made parts for today's manufactured products be they the gadget that makes beverage cans or the space shuttle. Among the precision items in current use in the trade are words. They have to have specific meanings in common usage throughout the country.

So when Gingery or somebody cooks up a gadget that falls in the category of a machine machine tool doesn't mean it deserves the generic name.

This has nothing to do with snobbish distinctions or elitism. It has to do distinguishing between good intentions and actual success. A surface grinder is a precision class of machine that among other things produces a precision ground surface flat within 0.00005 in any square foot and an non-acculative error of 0.0002" over its working envelope.

You won't get this class of accuracy by cannibalizing a radial arm saw frame or sliding stuff on a granite flat under a poised grinding wheel.

Someone with the skills and resources may very well produce a home made surface grinder meeting commercial specs.

Someone starting with cold rolled steel for ways or a belt sander for a grinding spindle will not end up with a surface grinder. He'll have a grinder of some sort or an abrasive belt finishing machine. See, you gotta create a new name for a new machine. "Surface grinder" is already taken and people depend in it meaning a certain thing.

I don't want to pour cold water on people building experimental machine tools or race cars or airplane or chili. I only want then to honestly identify the product of their hard work and genius, not borrow a name signifying performance orders of magnitude greater than that actually delivered.

Yeah, I'm a party pooper.


[This message has been edited by Forrest Addy (edited 02-06-2003).]

Spin Doctor
02-06-2003, 07:33 PM
No Forrest, you are not a party pooper. But I thank you for throwing a pail of water on this to douse the overly ambitous amongst us. I've been kicking around a design idea for a small surface grinder but working with precision spindles and slides on a daily basis I know what I would be up against. The well meaning amatuer doesn't. For most people that are doing machining as a hobby the best solution would be find a used Harig 612 even if it's in rough shape.

lynnl
02-07-2003, 12:26 PM
I disagree. The point is certainly valid that commercially engineered and mfg'd surface grinders reflect orders of magnitude greater precision than anything we of the 'Home Shop' tinkerer class are likely to cobble together. But a 'generic' term is just that.. 'general'. i.e. surface grinder (lowercase s, lowercase g). If it grinds, and it grinds surfaces, it's a surface grinder. If it quacks like a duck, ...oops, different story.. If some ingenious person needs and creates a device with limited capability to remove material too hard for other cutters, and produce a reasonably flat surface, using a spinning grinding wheel, you can't seriously expect him to name it a "Device- With-Limited-Capability-To-Remove-Material Too-Hard-For-Other-Cutters-Using-A-Grinding- Wheel" http://bbs.homeshopmachinist.net//smile.gif
Granted, confusion should be avoided by adapting one's terms to the audience. But I doubt the original post, asking about "building a surface grinder from a belt sander" misled anyone to visualize some highly precise machine.

Forrest Addy
02-07-2003, 03:37 PM
Here we enter "gold watch" territory.

In the early part of the last century traveling salesmen sold "gold" watches on the street corner for $5 (a full day's pay for the working man back then). The sales pitch was furtive as though it was a shady deal and the seller was desparate. How's the buyer gonna know polished brass from gold? The dial looks like genuine porcelain. The on the dial it says "Hamilton - 21 jewels - shock proof" on the case. What a deal! A $50 watch for $5. The case is brass and the works are brass. The watch is a counterfeit worth maybe 50 cents.

My dad bought one when he was a kid in the late '20's when he was following the harvest. He kept it for a lesson. Whenever I brought home a bargain he'd get out the watch and tell me the story.

Then there's the crow in the Aesop fable who found a peacock feather...

Then there's the guy who runs in from nowhere at the finish of the Marathon just ahead of the real winner...

And there's the fish story, the golf shot, the splendid girl you went with back when, we all have our deceptions but the most tragic is when we deceive ourselves.

(He had to beat me. I was bad. I love him. He'll change.)

(This job is temporary. I'm going to Hollywood.)

(It's only indigestion. I don't need a doctor.)

Standards have to be protected. Call it a surface grinder if you insist but be sure to follow with a brief disclaimer addressing the machine's limitations. Otherwise you become in a small way like the guy on the street corner proffering brass as gold.

There's no shame in falling short of a high aspiration or building what suits you.


[This message has been edited by Forrest Addy (edited 02-07-2003).]

Mike Burdick
02-07-2003, 04:30 PM
RGKing,

I typed in "surface grinder" in the search (HMS) Article Index feature on this web site. It located an article titled "A Make-do Surface Grinder" and is published in the 1984 Sept-Oct issue. It appears like it has two parts. Could that be the one your're looking for?

Mike



[This message has been edited by Mike Burdick (edited 02-07-2003).]

JCHannum
02-07-2003, 07:20 PM
Got to say that a homemade surface grinder is a homemade surface grinder.
If a person wants to manufacture a machine to perform some function in his shop, he should not be discouraged by semantics.
If it does not perform to the standards of a commercial machine, so be it. The maker has learned by the process, and may actually end up with something better.
If he is a determined individual, he will continue to develop his ideas and methods until an acceptable piece of equipment results.
A good example is the infamous lawn edger made by Deene Johnson. The fact that it is homemade does not make it not a lawn edger, and it is built like a tank. Much better than any available commercial units.
Making counterfeit items with the express intent to defraud somebody is a totally different situation.

Spin Doctor
02-07-2003, 08:09 PM
Neil;
Can we put a lock on this before it starts to get ugly.
When I originally posted a reply to this I failed to read the whole post and had a couple of cool ones. If I had noticed the part about the belt sander I would of done my best to throw water on the idea too.

Thrud
02-07-2003, 11:41 PM
I have to side with Forrest on this one. I can buy and have shipped an Taft Pierce surface grinder for under $3k - why bother try to build an inferior tool when Uber tools are availble "almost for free".

Despite the fact Guy Lautard is a great guy, the Granite slab based toolmakers grinder described in his "Bedside Reader #2" should NOT be attempted by most HSM's. It is a very dangerous tool as described and not for the safety conscience HSM.

RGKing
02-07-2003, 11:49 PM
Thanks for all of your replies. It really was just a matter of curiousity (and wracking my brain wondering where the heck I saw the article). I doubt that I would build one any way, and I don't have a spare 3k hanging around to buy a new or used one.

Forrest Addy
02-08-2003, 12:33 AM
Geeze RG. You're a match for the rest of us. Why izzit poor guys get into expensive passtimes like machine tools? Maybe rich guys got more sense.

Wait a minute. D. Thomas has more money than Bill Gates. How does that fit in?

Fred_Farkle
02-08-2003, 01:06 AM
OK. Here's two cents from a true newbie.

A year or so ago I purchased a Horrible Fright surface grinder. And I can offer assurances that it (and I) cannot obtain the accuracies stated by Forrest as required to be called a "surface grinder". So in this post I will call it the "little green beast" for short. LGB. First I will say that as a newbie, I rarely fail to obtain value from reading the posts of you "old guys", even when you disagree with each other. This thread caused me to think back a little on what has happened in my shop (and to me) since LGB showed up.

First I bought some cheap grinding wheels, with the grit/bonding compositions recommended for the material that I was going to surface grind. First mistake. Buy good name brand wheels. The cheap original wheels are now used to sharpen my 24" diamond saw. Second mistake. Wheel balancing. Without a trued, balanced wheel the surface looks like it was done with a hammer and chisel. After a couple of weeks on my Jet 9X24 lathe, I finally produced an acceptable taper to match my LGB spindle. Two lessons here; 1. looking for a good, used american lathe 2. learned a lot about setting up, calculating. and measuring tapers. Next stage. Building the balancer, settled on a magnetic design. Used a small herd of magnets of the type Thrud mentioned as used in hard drives. Bored a small hole in both ends of a 3/4 8" drill rod and silver soldered a "new" ball bearing in each end. Mounted my new Arbor on the drill rod. Made a stand with clearance to swing an 8" disc (wheel), mounted the magnets, with adjustment, hand lapped a couple small bits of Al. Put a wheel on the arbor, adjusted the magnets so that one end was in the air, the other end kissing the lapped AL.
Not a 30,000 balancer, but will unbalance with the weight of a postage stamp.

Put balanced, trued wheel on LGB, surface now looks like was hammered with a small chisel. Bought "tenths" indicator, much fooling around. Discovered by accident LGB spindle off by .003 measured from the spindle centerline. Learned how to make a split lead lap. learned how to spot, lapped spindle to form, corrected error. Tried again. Result wavy, heat checked surface. Learned about feed rates, (this is where I bought the name brand wheels) and how to better control the table movement. Tried again, surface looked like it had been ground. checked it with mic. Off by .002 in 6" More fiddling, found out that the table lifted when reversed. Have not figured out how to fix this so have to go past the work 2"-3" to get past the lift. Now can get .001 in 6" most of the time. LGB weighs 800 lbs, the table 120 lbs.

Now I use LGB to sharpen chisels, form screw driver tips, cut shanks on mills/drills, form points on wigglers/indexers etc etc. Rarely do surface ginding.

moral of the tale - It may not be a surface grinder, but it sure as hell is a high precision bench ginder with a odd shape. And I learned to do things that are, and will remain valuable to me. Never been in a real machine shop - would love to watch some of you guys ply your trade. It may not be up to aerospace standards, but with a little help from you guys, us newbies will get by with what we can manage.

Mike

PS - In my very limited experience, an amateur can obtain accuracies to 001, when needed, by paying close attention to first principles. Obtaining and reading carefully machine tool references, especially the older texts. Lurking on forums such as this one, asking questions. Scavenging parts from salvage yards, surplus outlets. Spindles, ball slides, ball screws and so on. But, in the end, for consistent result, good finish, mass is required. If it ain't heavy, accuracy will be elusive. I buy the heaviest iron I can afford and handle safely.

[This message has been edited by Fred_Farkle (edited 02-08-2003).]

wmgeorge
02-08-2003, 11:18 AM
Answered my question about low cost surface grinders! Has anyone had any "good" experiences about the low cost HF or other surface grinders?? B.G.

lynnl
02-08-2003, 01:43 PM
My disagreement was NOT over the machines, or their capabilities, but over the 'wordology'. Certainly in the professional machine shop world if a person says I've acquired a new "surface grinder", that statement, to another machinist, will invoke an image of a high quality, high precision machine as described. But to assert that on a "Home Shop Machinist" forum the use of those two words (preceded by 'homemade') to describe something of obviously lesser quality, is somehow forbidden, is in my opinion elitist... just as if Mercedes Benz and/or Rolls Royce were to try to reserve the word 'automobile' for only their products.
But...that's just my opinion. I bear no rancor or animosity toward anyone (or possibly everyone http://bbs.homeshopmachinist.net//biggrin.gif) with a different view.

BTW, on the subject of surface grinders: a few years back there was a company here in Huntsville AL that made what a feature article in the local newspaper described as some of the most precise grinders in the world. These were not mass produced, but rather one at a time, as orders were received. These were very large, very high dollar items (maybe 1-200K per machine). It was a small family business that had been making these for many years. The name was Aldrich, as I recall. Has anyone here ever heard of such a machine?
I happened on to their shop on an obscure deadend street once just a block from where I work. But that place is now closed, so I'm wondering if they're still in business.

docsteve66
02-08-2003, 08:48 PM
fred: made me feel good to read your post!! In my opinion, you have learned how to do lots of things you would learn had you purchased a first class machine in good shape. You need three things to learn a lot- A champangne appitite, a beer wallet, and an unwillingness to go into debt. http://bbs.homeshopmachinist.net//smile.gif

I bet you learned more real mechanics from the LGB than you would have from most any formal training- you you must havelearned how to learn .

Congratulations!!!
Steve

Fred_Farkle
02-08-2003, 11:30 PM
Thanks for the good words...

Stubborn as hell


Mike

Thrud
02-09-2003, 02:20 AM
Lynn

"New" means "new to me" - used is also just "new to me". "Virgin", is another matter - that is unsoiled by others grubbies, free of defects "hot off the press".

brunneng
02-09-2003, 07:01 PM
As a HSM and not a professional machinist I'd say that a name describes a function and the specifications tell part of the story and reputation tells the rest of the story. Bear with me.

It seems that most of the people on this bbs have at least one chinese caliper. I've never heard the ones who can afford Starret, Mitutuyo, etc tell them that they don't own "real" calipers and should stop calling them that. The real difference is in the specs and performance. When they think it's needed everyone here qualifies their questions and comments with how they did it and with what it was measured (this was done with an import caliper, that was done with a Starret mic).

To a concrete guy - flat is one thing, then there's the woodworker, HSM, Pro Machinist, Tool and Die dude and then there's the ones who make top class gage blocks. They all have different definitions of flat and precision and none of them are wrong and we probably have all of them on this bbs. (oh, and I know that the concrete poured for your patio isn't done to the same level as an aerospace work floor)

My home shop of tools is probably worth $4k in total at this point because that's what I can afford so there's nothing simple about a $3k grinder. Everyone to his own needs, wants and wallet.

I'm just saying that we need to remember that we are all at different levels on here and are joined by a love of tools and metal.
Can a HSM make a high quality, high precision surface grinder? YES.
On the first try with only a file and hacksaw? maybe if he's got 20 years.
If he can cast parts - better.
If he has a mill and lathe of required accuracy for rough work - better still.
Learnt scraping? - now we're starting to talk.
precision measuring tools and gauges. - Can't hurt.

Remember - EVERY machine was made once in a shop by someone who hadn't made one before. Many in shops that weren't was fully equiped as some of ours. After all, why did over 100 people buy books on scraping if they didn't think they could restore something back to "factory" or better.

Here's a link to a set of plans for a small, surface grinder. It could probably use a lot more weight. Think of it as a "dremel" surface grinder (it's not made with dremel parts tho). It's from Model Craftsman Magazine, August 1937.

http://www.dm.net/~lughaid/vest.htm

That's my soap box for the year.
Kevin

wmgeorge
02-09-2003, 07:36 PM
With todays used machinery prices so low... you can get a name brand used surface grinder for $500 to $2000. Granted it will be 3 phase but you can build a static converter for most 1 HP grinders for less than $100, I built mine for 1/2 that using capacitors pulled off used AC units.

Here in Iowa used ones at dealers can be $3000 on up, but if you watch ebay auctions you can get one for the above prices within driving / hauling distances.

I'm going to guess right off hand you can not build a surface grinder for $500... even if you consider your time is "free". Sure its fun to build things, and I've spent my time building stuff that I could of just well went out and bought new, but a surface grinder I would not attempt. B.G.

Fred_Farkle
02-09-2003, 08:02 PM
I would let LGB go in a heart beat if I found a commercial surface grinder, that was within my skills to restore, for 500 bucks!

Can't travel further than the LA area. Point one out and I'm off like a shot.

Mike

PS Kevin - Thanks for the link. I went and looked at it. Is it possible to get the drawings so they can be read. I don't know about a surface grinder, but on first glance, it looks like it could be part of a great Tool & Cutter Grinder. Sorry. I mean a thing with a thing that does a thing with abrasives.

[This message has been edited by Fred_Farkle (edited 02-09-2003).]

spope14
02-09-2003, 08:46 PM
Built my own wood lathe out of plans from a "Projects in Metal" book, works great!!!

I say if you keep safety in mind, be careful, and do things right, try to build the thing.

One must remember the guys who built a lathe in a prison camp in WWII out of some scrap parts, and all sorts of other things. Saw this in the Bedside reader, and though not sure, believe it is on display at the American Precision Museum in Windsor VT (The Mecca for the HSM)

Somebody had to build the first machine somewhere, and people are always making speciality machines. After all, the guy who makes all the velcro making machines is in my neighborhood, and he does this in a way that you would look at the job and go "huh"? but hey, if you trapse around your home, you will find velcro, and will find it probably works just fine in the end.

Dave Opincarne
02-09-2003, 10:47 PM
As someone who has run a surface grinder in a tool and die shop and also enjoys bodging things together in his own shop, I'd like to pose a question to both the people wanting to try this and for those saying don't think of such a setup as being able to produce results comparable to those devices commonly known as "surface grinders".

How much material are you planning on removing? What do you see as a reasonable expectation for a final pass? And what sort of tolerances do you expect to achieve on any machine YOU consider a surface grinder?

Reading the posts from those members who are purely self taught hobbyists (and speaking in sweeping generalities of course), I'm forming the impression that expectations may be to high for the amount of material a surface grinder (I'm speaking of commercially available quality units) is able to remove, and may be to low when looking at the finished tolerances a grinder is capable of producing.

On the other hand, I do think that machines like those described in TMBSR are capable of producing quality work for the home shop. And doing it safely. The description of the surface plate grinder very clearly states the belt should be very loose; loose enough to easily stall the wheel.

In both cases (commercial and cobbled) the work peice should be within a few thousandths of final dimensions and the grinding wheel should be advanced a few tenths at a time. Think of the grinder as operating on the next order of magnitude from the lathe and mill. If a finish cut on the mill is going to be a few thousandths, then on a grinder it’s going to be a few tenths.

A few people in this thread have equated mass to accuracy, and while I agree it's an important factor it can be compensated for. Four more important factors in the case of a grinding operation are: 1) the trueness of the wheel (Mike, I didn't see you mention truing your cheep wheels before diving into the spindle) This is different than balancing the wheel. The wheel needs to be dressed every time it is started. The wheel will jump off center when it is started due to the small play between the wheel and spindle. 2) Quality of the spindle bearings. They don't HAVE to run without friction, but they do need to be able to run smoooooth. Hardware store bearings aint going to cut it, but the innovative hobbyist should be able to come up with something innovative. 3) The ability to bring the wheel and the work together in fine increments with precision and accuracy. For the homemade design I would stay away from any sort of direct feed measurement like lead screws and improvise some sort of closed loop direct reading system using gauge blocks or a mike head and a tenths reading dial test indicator. Which leads me to the last point 4) measuring tools capable of inspecting your work after the first complete pass (in order to zero your feed) and to inspect the results. This is a situation where even the Starett calipers (let alone the Enco's) aren’t going to cut it. If you’re not measuring with at least a quality tenths reading mic then you aren’t going to be able to utilize a surface grinder. I don't mean to sound harsh, I'm just trying to underscore my original question. Homebuilt or made in USA tool room quality, a surface grinder is a tool for dealing in values smaller than 0.001"!

Thrud
02-09-2003, 11:46 PM
Kevin
I have always been an advocate of buying the best that a person can afford. I myself have to make comprimises everyday in my life - we all have different levels of commitments we must attend to before playing.

My point in mentioning a $3,000 (shipped here from the US with duty) is that it is immently difficult to even come close to the accuracy a machine such as that can deliver - anything I build is not going to do an equivelant job. Besides, I find it interesting that a machine that sold for nearly $50k in the fifties is so cheap considering its excellent condition.

Fred_Farkle
02-09-2003, 11:58 PM
Dave - A thoughtful and useful post!!

The sequence was this: Leveled LGB, oiled same, played with feeds with power off, removed wheel guard - checked arbor nut, mounted wheel guard, turned on power, turned off power, mounted magnetic chuck, used .001 indicator to square magnetic chuck to spindle, mounted diamond dresser in holder, spent two days trying to find a picture on how to place the diamond relative to the wheel, found picture, marked wheel working surface with a marking pen, turned on LGB and advanced wheel feed 0005. and made a pass with the cross feed, no contact, indicator said wheel fed .004, stopped motor, removed diamond, made sure wheel head counter weight was free, found wheel head gibs were to loose, adjusted for noticable friction of wheel feed, used paper strip to bring wheel into contact with diamond point, started motor, very slowly adjusted wheel feed until just barely sparked, zeroed .001 indicator, moved wheel free of diamond with crossfeed, set wheel feed to .001, made a pass with cross feed, continued until all traces of marking pen were removed from wheel, vibration of LGB was apparent, but less after trueing wheel, dismounted and clocked wheel several times, vibration would change, wheel would require trueing again if wheel clocked...times passes...used new spiffy home built balancer to balance wheel and arbor, installed same, trued wheel, vibration now much less...more time...checked spindle runout cold .0004, after running no load 20 minutes, runout now .0002, not bad...more time...lapped arbor face checked for movement with indicator, found .004, removed wheel, checked spindle and found the .003 stated above, gooped up arbor with dykem, installed pulled off and found high portion of spindle, lapped it out, re-installed everything, trued wheel, ran no load 20 minutes, run out at lapped arbor face now same as spindle run out +- a tenth. Vibration now be gone.............much time passes as above, new wheels yadda yadda.

When a surface grind a part, the material I remove is usually .002 to .006, removing tool marks from the part and bringing it to dimension +- .001. I set the feed to .0005 and use the cross feed until it's mostly sparked out, then another .0005., and so on.. I have to use the indicator because the down feed will still slip on me, it is indeed, a screw feed. If I adjust the gibs tight, the feed stick-slips, too loose it feeds on its own.

I talk about weight because of experiences with faceting machines. The cutting force of the machine, is into work AND into the machine, the abrasive process is also stick-slip, and will create harmonic stresses that can be compensated to some extent by weight. Constant or predictable harmonics may be dampened by design, if not predictable, then throw a few more hundred pounds on the beast and plow on...

Mike

PS Are not commercial surface grinders a tad on the heavy side?

[This message has been edited by Fred_Farkle (edited 02-10-2003).]

Dave Opincarne
02-10-2003, 01:44 AM
Thanks Mike. What you describe sounds about right. It wasn't clear to me from your initial description that you had dresses the wheel prior to taking the hammer and chisel to your work piece.

My point reguarding mass was not that it wasn't important, but that there are other factors more important which will negate the benifits of mass if not kept in mind. For example, if a wheel is not describing a true circle (due to either to an untrued wheel or bad spindle/bearings) no amount of mass will help.

My coments were directed twords those contemplating building their own grinders. Vibration dampening mass is important, but the other factors I mentioned need to be considerd in order to get quality results.

yf
02-10-2003, 12:27 PM
A friend of mine told me that some people building their own machines fill the bases with loose sand to absorb vibration.

I have read about concrete being used during WW II to form massive bases for large machines, as cast iron was in short supply.
Its relatively cheap, you don't need a foundry and the forms can be wood, plastic, anything. I saw an article from the war years about building a home made milling machine of concrete. Steel inserts were cast into it to hold the bearings etc.
Very intresting.

BTW the Taig lathe's bed, is filled with concrete.

spope14
02-10-2003, 12:47 PM
Found the pln for this unit, September October 1984, have it in my hand as i type. Scary looking thing I will admit. basicaly a hand grinder put on its side, or also a radial arm saw with a cutoff blade on it.

I would not make it....however would look to design something better, probably would cost as much to make it as to buy a chinese knock off...

mentioning sand, there is a 20 foot long lathe in Windsor VT that has a granite base and ways.

Fred_Farkle
02-10-2003, 01:01 PM
Dave - Thanks for your posts! It took me a little over a year to get LGB to the point I could get .001 in 6". Your posts would have saved me most of that year!! Oh well...

The knowledge you shared also caused me to think about just why in heck I have a surface grinder in the first place. It really is a good question. I'm a hobbyist, working my way toward becoming an amateur. And, yes, I have the disease. I lust for tools, an addiction that is worst than drugs, totally incurable. No hope. If I could get a Swarfblaster 2000 (makes Volkswagon with one push of a button), I would get it in my shop somehow.

For the class of work I'm capable of, and the parts I make, I really don't need a surface grinder. On the truly rare occasion when I need a part ground, I should take a few nickels and the piece down to my local job shop and get it done. They will do it right, and we need to keep the real machinists around so we can ask them questions. LGB has turned into a strange looking bench grinder. I use it quite a lot for all sorts of stuff. A good example, got myself a fixture for grinding end mills. Now there's a tale worthy of a post or two. Not much surface grinding. Most of the surface stuff I do is for appearance. As a lapidary hobbyist also I'm blessed/cursed with a surface finish fixation.

If I had to do it over again, I would have done what I'm doing now. Learning how to scrape. A good scraper or two, a grade b granite surface plate, some canode spotting ink, (don't use dykem hi-spot unless you want to keep explaining to people why your gradually turning blue). The bible on scraping, the dapra video is really is worth while, and a huge, continuing investment in diligent practice. You then can make a surface, fit a surface to "tenths".

I will still run off and buy a used, commercial surface grinder if the price is within my means. But here's my problem. I don't know anything. And I would never commit hard earned money to total chance on e-bay or other auction outfit for a used swarfblaster 2000. I don't have the knowledge to tell the difference between a machine that was used by a little old lady for the one off part, and is premo. From the equally good looking machine that is worn to the pins from 1,000,000 part a day production. And here's another problem, your swarfblaster 2000 has got a small part or two broke or worn, call the swarfblaster 2000 rep, not a problem, send it right out, That is, right after I sell my 2nd cousin into slavery to make the price for a commercial repair part.

Again, don't get me wrong. If you pro's advise getting a such and such machine, I want to follow your advice. I respect your experience and value your knowledge. Please keep it coming, but, if you don't mind, add a little advice about what to look for in a used machine.


Mike

Dave, thanks again.

Fred_Farkle
02-10-2003, 02:29 PM
yf - very interesting stuff..

Mike

Dave Opincarne
02-10-2003, 07:27 PM
Mike (and others), I don't recommend the Swarfblaster 2000 - Outdated technology, high tooling costs, steep learning curve, etc. Basically a beta version that found its way into production. I recommend you hold out for the MegaSwarf 2K3 which features a CARBON FIBER squirrel with titanium nuts.

Seriously, I... well first a bit of background.

I'm currently working as a pattern maker, but most of my pro experience is as an aerospace toolmaker (composite tooling and tooling for composite parts). This work does require machinist skills, but not continuous machine operation. I have worked in a tool and die shop for a time, and I've moonlighted as a machinist for brief periods. That said I didn't get into the trades thru the usual means. I used to be a commercial photographer who wanted to develop some product ideas. On a photo shoot to photograph a rather unique individual who had developed an innovative bike design which relied heavily on CNC operations I was inspired to try and develop my ideas. After talking to some guys in job shops, cruising the used equipment dealers, and a couple of copies of HSM I invested in a JET mill/drill and set it up in a spare closet. What I also did was spend a fair amount of money on vocational texts and spending some time in the engineering library reading any machine text I could find. Also, my original major in college was mechanical engineering so I had the layout experience from drafting courses and plenty of geometry and trig skills. I found I was more interested in the challenges of machining than in the original products I wanted to develop. I found an entry position at a pattern/tooling shop, one thing lead to another and here I am.

The reason I’m providing this little bio here is I think its important to understand a little of my background in order to qualify my position on the validity of home built machines, other operations such as scraping and lapping, and any other improvised techniques.

Now, where was I? I believe the truth in the old joke about your choices being good, fast, and cheap-pick any two. If the person in the small shop (be they hobbyist or inventor) is willing to trade time for quality and economy and is capable of thinking in an innovative manner then they should be able to achieve their goal. I’ve never understood the view of many people in the trade that a higher quality (define quality how you will) tool is required to produce a lesser quality final product. The toolmaker is in the business of turning sows ears into silk purses. As a species we didn’t start off with tools infinitely more accurate than those we have now; we started off with sticks, flint, natural fibers, hide, sinew, and the like and ended up with things like the space shuttle, Weber gauge blocks, and CNC 5 axis machine centers. Now the real beauty here is that having taken 10,000 years of trial and error to do this the first time, we should be able to move much faster along smaller segments of this technology line the next time around. One of my favorite examples is the ability to make an accurate surface plate using nothing more than the material for the plate itself, tools to work it with, and spotting compound. The only trick is you need to make three at a time, working A to B, B to C, and C to A repeatedly until the required level of accuracy is achieved. Having a precise and accurate reference surface you can now go on to create other gages and tools required to produce accurate machine ways or work the workpiece directly through chiseling, filing, scraping, and lapping. What’s required here is the ability to manage the triad of quality, cost, and time. While it’s entirely possible to develop a CNC grinder in the small shop using first principals, doing so is going to draw heavily from time and finances. Doing so in order to make a couple of gauges is ridiculously inefficient. However, purchasing some relatively inexpensive reference tools and making or restoring a machine tool capable of meeting the one off needs of a small shop is entirely feasible.

What it comes down to is this: If I need a couple of precision surfaces, I’ll scrape, lap, or outsource. If I’m going to need such surfaces intermittently but repeatedly I’ll make/renovate a grinder capable of fulfilling my needs with the understanding that such a machine is going to require slow light cuts. If I need to produce ground parts on a production basis then I’m going to have to think about buying/building a grinder capable of churning out some work on a daily basis. All I’m doing is matching my operation to my requirements, but at no time do I have to give up quality. The key here is “Economy of Scale”.

Speaking of economy of scale, I’m interested in any information on the use of concrete, granite, sand, weldement, and preloading columns in making machine tools. If anyone has any information please post it or e-mail me. I’ve been interested in casting concrete machine beds on a surface plate and adding ground or scraped ways in order to produce a one off machine. For manufacturers it’s economical to cast and machine a tool out of iron, but I’ve never been able to think of a good reason why stone or concrete wouldn’t work well so I find it interesting to see others mention times when this technique has been used previously.

This has gotten long, so I’ll try and wrap this up after addressing Mike’s question regarding determining how gently a tool has been used and how much life is left. I’ve worked on well maintained tools and mills that are barely usable as a drill press. My best advice is to USE YOUR EYES. If the machine looks like it’s been taken care of and been used only by qualified individuals then it probably has. If the table or ways show signs of abuse then it’s a safe bet that the machine is going to have problems and be a headache It was either abused by people who didn’t appreciate it or every last bit of life has already been sucked out of it. You’re better off investing in a new import and looking at it as a kit. Look for wear on the ways, compare the end of the ways from the middle. On mills most ways are scraped and the wear will appear in the middle of the X axis and at the top of the knee way. If the frosting is worn away as compared to the ends of the ways then the ways are shot and are going to need to be reworked. On lathes most of the wear is going to occur near the head stock. Compare the look of the ways near the headstock to the area around the tailstock. Check the back gears, half nuts and feed controls! These are often broken by someone who thought he knew what he was doing and didn’t. These gears can be difficult and expensive to repair. Stay away from odd tooling requirements unless you’re willing and able to make your own. Stay with R8, Morse Taper, C5, and common spindle noses. Signs of neglect such as surface rust can be dealt with (and may indicate light use), but signs of abuse are going to cost you money/time/quality. If the machine is being sold for a song (and a short song at that) and your willing to put in the time and/or money and/or give up quality then go for it.
I’m sorry this has gotten so long, but I want to address one more thing which may help some of the people working at home and shed some light on this thread. I’ve used the words “Precision” and “Accuracy” together and separately in some of what I’ve said. This is not redundant nor are these terms interchangeable. Accuracy refers to how close you’ve come to the value you’re trying to achieve. Precision refers to the ability to achieve consistency and repeatability. If we make an analogy to a target then the terms can be defined thus: Accuracy is the ability to hit the center of the target while precision is the ability to achieve a tight grouping. A micrometer that is accurate but not precise may be calibrated but have faces out of parallel or a frame that flexes or expands making repeat measurements difficult. A micrometer that is precise but not accurate will give the same reading repeatedly but always in error. We should keep these definitions in mind when discussing the merits and viability of improvised versus commercially produced machine tools or considering alternate methods.

Thanks for listening

-Dave

Fred_Farkle
02-10-2003, 08:36 PM
Dave - What can I say! Thanks again.

Mike

PS MegaSwarf 2K3? I think I got a line on one down in LA at the Used machinery & potted plants emporium. I think I'll take my eyes down there and have a look Need to start some where on this "learnin" business.

yf
02-11-2003, 03:34 AM
Dave,

As far as building machines useing concrete,
There may be a better material available today.

A friend of a friend, that I met some years ago, was (is?) a salesman for Cincinnati Milacron. He mentioned that they were building some especially massive machine bases from a new epoxy type material.
He said plastic and when I asked what type he wasn't sure. When I asked, epoxy? he said yes that's it. He also said that these machines were even costlier than their cast iron counterparts.
That really did not make sense to me.
He said that machines built from this material were performing better than cast iron.

I haven't seen him for about 6 years now.
I searched for a website and found that Cincinnatti Milacron sold off the metal working machinery parts of their business and changed the name to "Milacron".

I don't know any more about this material, but you may be able to find out more from the successor company. I believe that is Cincinnatti machine.

Does anyone have first hand experience with plastic, heavy machine tools? http://bbs.homeshopmachinist.net//biggrin.gif

Every thing seems to be made of plastic today, and in china or mexico.
And not very good quality.
I would think that most of the cost of something made in china would be shipping.

That's something that can't be done in china http://bbs.homeshopmachinist.net//biggrin.gif
(At least not to here)

darryl
02-11-2003, 04:14 AM
Concrete bases, cool ides, I think. I made myself a poor man's surface plate, or should I call it a mediocre flat mounting plate, out of an automatic tranny casting, the piece with the hydraulic passages in it. It is cast iron, and I embedded it in concrete, filling the holes as well. It's full of threaded holes, 5/16 inch, so I can mount almost anything within size to it, for truing while assembly, or before brazing, etc. Two thoughts on this now, can I epoxy a piece of glass to the surface, and get an (almost) surface plate, secondly, I've wondered about temperature variations, will the metal/concrete combo have warping problems if heated much. I was careful to cast it at room temperature, using a slower setting concrete, and to date, I haven't seen chipping or cracking, but I don't always check to see if it's still flat. By the way, the benefit from using concrete is rigidity, and epoxy is not generally rigid. I can't see it being better than concrete if used as described for lathe beds or similar.

[This message has been edited by darryl (edited 02-11-2003).]

Chris Fazio
02-11-2003, 11:51 AM
yf

These types of materials are sometimes called polymer concrete. They are composed of mostly crushed granite and a small amount of 2-pt. room temp. cured epoxy. They claim it has dampening properties many times better than cast iron. You can check them out at www.phillyresins.com (http://www.phillyresins.com)

Chris

brunneng
02-11-2003, 09:29 PM
I remember an article in Wood magazine back maybe 10 years ago. I think I still have the issue, have to find it. In it, a bowl turner, who turns 300+ lb hunks of wood into bowls, made his lathe because he couldn't get one heavy enough to dampen the oddsized, unbalanced rough wood blanks.

He poured a 1500 lb block of concrete in a form and bolted his bearing blocks to the top for the shaft to mount the blanks on (tree stumps). It was trapazodial (think solid a-frame), wide base narrow top.
No vibration from a rough 40" dia, 300lb block of rough wood spinning at 300 rpm.

I've been working out a form of the same style for my mini-mill to mount on. It will be half the weight tho. I bought leveling pads of the appropriate strength to support and level the whole thing. I was planning on making the shell out of sealed plywood with hotwired, bluefoam cores. I'm using the rigid foam in compression only and it will be colapsable after curing for easy removal. Plus it should leave a nice finish and it can be shaped into coves and such.

--
I was looking at making the small grinder I posted the link for(or very similar, taking advantage of 80 years of development in off the shelf parts) to finish the mating surfaces of small 2" square aluminum blocks I use to make molds for my small benchmount plastic injection molder. Very light cuts, very little removal. It spins a 4" or smaller wheel.
So maybe the efforts overkill. I think it would be a nice little machine and good experience. If it doesn't work out, I've still gained experience and had a good time with my tools. So it's win-win. I plan to scrape some parts. Might have a shop grind some parts. Hey, I might even come out with something that's much safer and worthy of print.

And someday I plan on getting a "real" surface grinder - right after the bigger lathe and mill.

Kevin