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Black Forest
02-09-2016, 07:01 AM
I want to buy a surface grinder. It doesn't need to have all the bells and whistles but I don't want to hand crank a table back and forth so it has to have auto whatever you call it back and forth.

What do I need to look for or look-out for especially? Used would be good as I probably won't use it much but it would be nice to have.

Did I mention I don't know anything about surface grinders other than what I have watched on YouTube or read on here. I only ever seen one work one time but that was a big one grinding some 1500mm parts for me.

Carm
02-09-2016, 09:17 AM
Unless you have some of that 10 million left, used it will be. Being in Deutschland has me at a loss, I'm not too familiar with German stuff, though I've never seen junk. Doubt there is any 'Murican iron over there.
Manual doesn't need be a deal killer, I've seen some hydraulic adaptations in Amish shops, where it's either fluid and/or air anyway. Best if the transition is outside the envelope.
The larger the grinder, the less wear will affect precision in a smaller envelope.
My own SG has bronze spindle and iron/oil/iron ways. If needed, I can re-fit in house. Some grinders with roller ways can be swapped out with not much work, I have a contact for replacements somewhere, but they'ré in the US so doesn't help much for you. Rollers need more care in transport.

A good deal would include mounts for the rocks, Sopko or the like, unless you do the same thing all the time.

Toolguy
02-09-2016, 09:27 AM
What I look for in a surface grinder is a wheel elevation crank low and in front. Many of the smaller ones have that at the top of the wheel tower in back. That is an awkward and tiring one to use, with your arm raised and stretched out. Low and in front lets your arm hang naturally at your side. It seems a small thing until you have to do it.

Another item to look for is a common spindle taper. Here the Sopko is the most common. It makes getting tooling easier and cheaper.

I prefer hydraulic operation of the table. My grinder has electric actuation for the Y axis, hydraulic for X.

Get a fine pole magnetic chuck, electro magnetic if possible.

boslab
02-09-2016, 09:34 AM
The only German beasts I've had a go at were Jacobsen, Jung and a unintelligible cnc by SKF which terrified me to be honest, I used to have a dig on surplex for stuff as shipping was free as we had lorries buzzing about with coils of electrical steel in Germany
https://www.surplex.com/en/m/7/jung-flat-grinding-machine-320808.html
I am in no way up on surface grinders btw, anything I did was extremely basic and usually only achieved with the help of the guys in the grinding department, looking at a ground surface does give me goosebumps btw, it takes it from metalwork to engineering proper imho.
I do have a radius attachment lying about if you need one, needs a fix
Mark

Jaakko Fagerlund
02-09-2016, 10:18 AM
Jacobsen grinders are good and plentyful around here. The basic model that I've seen is hydraulic powered XZ axes and stepper motor controlled Y that is controlled with a simple logic unit that you use to set the amount to take off. That one has a manual dressing unit in the side of the wheel.

A bit more sophisticated Jacobsen has automatic dressing operation and is thus pretty much a set-and-forget machine.

Of course it is easy to make and adapt whatever lower end of the scale to your own needs, I would for example get a simple hydraulic powered machine and fit it myself for fully automatic operation.

Tony
02-09-2016, 10:32 AM
I'm new to grinding -- and in a very trial by fire kind of way -- so take this with a grain of salt,
but to answer your questions on what to look for, I can tell you what I found after buying my
old grinder sight unseen. More or less it's what you'd look for on any used machine:

- table, etc still has full range of motion (over tightened gibbs to hide wear)
- shove the table/head/spindle around see if there is any slop
- see if the locks work.. and how far you need to swing them to actually lock
- mag chuck work? how much of its original 'stickiness' does it still have? :)

asking to grind might be obnoxious.. but table dip left/right or front/back would be nice to know,
but this goes with the whole 'wear' thing.

for what its worth, I don't find a manual table that annoying.. heck sometimes its almost
relaxing.. but then again I don't do all that much grinding and when i do the stuff is
usually pretty small.

get one, you'll love it.

Tony

JoeLee
02-09-2016, 11:53 AM
My KO Lee has the hydraulic table and infeed and I never use it. Most of the time the parts l grind are small and I would rather be in control of what I'm doing.

JL..........

metalmagpie
02-10-2016, 10:42 AM
I don't have a ton of experience but I have owned one and used several. I have never successfully achieved a commercial grind finish with a small 6x12" grinder. And I have gotten great results from a Taiwanese (Chevalier ) machine with hydraulic feeds. Ball ways are very desirable.

metalmagpie

boslab
02-10-2016, 11:01 AM
Can't argue there, not a brilliant finish with a little eagle, ok but not somthing you would expect from a grinding shop, myford do a nice small cylynder but I've never seen a flat grinder from them, most around here go for Jones and shipman, nice finish fairly easy to handle
I've never taken one to bits to find out what's inside!
Mark
Wouldent turn my nose up at an eagle if only for sharpening!

JohnMartin
02-10-2016, 11:03 AM
Another item to look for is a common spindle taper. Here the Sopko is the most common. It makes getting tooling easier and cheaper.



Sopko make adapters to fit the different tapers of almost all grinder spindles - there is no one "Sopko" taper. That said, the Sopko adapters are not cheap, and one may be better off with a spindle that takes one of the sizes that are commonly available on the used market.

Jaakko Fagerlund
02-10-2016, 04:11 PM
Can't argue there, not a brilliant finish with a little eagle, ok but not somthing you would expect from a grinding shop, myford do a nice small cylynder but I've never seen a flat grinder from them, most around here go for Jones and shipman, nice finish fairly easy to handle
I've never taken one to bits to find out what's inside!
Mark
Wouldent turn my nose up at an eagle if only for sharpening!
Ah, forgot the good old Jones and Shipman grinders :) Have a cylindrical version and a surface grinder from them at work, both are awesome and after decades still do accurate and flat work.

projectnut
02-10-2016, 05:30 PM
Other things to consider are how often do you intend to use the machine, how much real estate can it occupy, and how much are you willing to spend to outfit it?

I know you mentioned you didn't want a manual machine, however if real estate is tight and it doesn't get used on a daily basis a manual machine might be worth looking into. I have an older 6" x 18" manual machine that only takes up about 4 square feet. The table needs another foot in each direction, but all in all it's a fairly small footprint. I only use mine a few hours a week. Given that space is at a premium I wouldn't want to dedicate another 6 to 10 square feet for all the support systems need for an automatic machine.

I've used semi automatic and fully automatic machines in the past. With the hydraulic pumps, motors, reservoir and plumbing they take up a lot of floor space. In addition the larger the machine the machine the greater the cost for tooling . A couple years ago I had the chance to buy a DoAll 8" x 24" hydraulic machine in like new condition for less than $800.00. It was a great machine, but way to big for the floor space I could dedicate for it.

My grinder uses 7" wheels which are readily available for $20.00 to $35.00 depending on the width, profile, and composition. I currently have a couple dozen wheels in stock. The total cost for wheels is probably less than $500.00. 10" wheels generally cost $50.00 to $100.00. It would triple the cost of grinding wheels to go to the larger size.

Just a few things to consider when shopping.

rickyb
02-10-2016, 08:31 PM
Keep in mind that grinders are trued up by grind in the surface of the magnetic chuck. When looking at a machine indicate the table X and Y to actually see how much the machine is worn. I bought a manual 6x12 inch grinder where the chuck was true but the table was out 0.5mm over the 150mm Y axis. X was no better.

Lu47Dan
02-10-2016, 08:44 PM
A few thoughts on the SG I bought.
I bought a Boyer Schultz 6 - 12 Deluxe when I bought the two mills. I paid less for it than commonly paid as it was in pieces and needed a few parts bought and made to put it back together.
I have sharpened allot of chipper/shredder blades with it, for people in the area. After the jig is built I charge $15 - $25 apiece to sharpen the blade. Some of the blades are no longer available, and I am in the process of getting everything ready to make a few sets of blades for my chipper/shredder. Having a SG enables me to sharpen used blades and to finish grind the new blades.
Electro-magnetic chucks are fine, but they are not really necessary, sure they nice for very thin stuff, as some of them the holding power can adjusted.
But a manual chuck will work well with less problems.
Fine pole chucks are better for small parts, but work just fine for larger parts. The inverse is not true for large pole magnetic chuck. The larger space between the poles make holding small parts a tenuois operation. I have ejected small parts from one SG in vo-tech that had a larger gap between the poles.
The learning curve on a surface grinder can and is rough. It is fairly easy to blow up a wheel if you get in a hurry.
The proper wheel of the proper girt and structure can improve the durablity of the wheel.
Which ever SG you buy get a half dozen wheel adapters to mount a variety of wheels on. This way you can have a wheel ready to go, and just swap out the mounted wheel.
Unless you are doing production work, a powerfeed table is not really needed. They are nice but can and do take up a lot more room.
Dan.

boslab
02-10-2016, 09:46 PM
I must admit on my first go at grinding I was a bit shy, scared of the wheel popping, I'd geared all sorts of tales, but they are more durable than I first presumed, provided they are checked for cracks by ringing, properly mounted with paper washers, balanced and so on.
When I ground my first bit of work the grinder asked me in a rather stern voice if I was going to grind the bloody thing or polish it into submission, what he told me was all I was doing was getting everything hot with poncy cuts.
I admit I wasn't taking much off, he had a go and went right up to size in very few cuts last one being light after a cup of tea!, Britain and tea!, the work was flat and to size, my puny effort resulted in bowed and undersized as the work was hot it shrunk when it cooled, I found out I'm no grinder, just a pretty finisher!, but it makes me happy, I do miss not having these machines available to use when I like, I'd have to win the lottery to get all the machines we had in just the technicians maintanance shop.
I would like a surface grinder but I don't really need one, similar to shaping machine I think!
Mark

Spin Doctor
02-11-2016, 06:12 AM
I'll throw my 2˘ into the pot. If you plan on doing small items a manual 6x12 is fine. Ball or roller ways, not for me. I've seen too many things with the pattern of the rolling element. In my mind the big complaint I've got about most manual grinders is the table traverse is on the left side and most people are right handed. Harig's used to come both ways. The elevating hand wheel is at the top of the collumn but on a right handed machine you use your left hand to turn that. As with most machinery supplemental tooling raises its ugly head. Magnetic parallels, vee blocks, angles etc.

projectnut
02-11-2016, 09:01 AM
A few thoughts on the SG I bought.
I bought a Boyer Schultz 6 - 12 Deluxe when I bought the two mills. I paid less for it than commonly paid as it was in pieces and needed a few parts bought and made to put it back together.
I have sharpened allot of chipper/shredder blades with it, for people in the area. After the jig is built I charge $15 - $25 apiece to sharpen the blade. Some of the blades are no longer available, and I am in the process of getting everything ready to make a few sets of blades for my chipper/shredder. Having a SG enables me to sharpen used blades and to finish grind the new blades.
Electro-magnetic chucks are fine, but they are not really necessary, sure they nice for very thin stuff, as some of them the holding power can adjusted.
But a manual chuck will work well with less problems.
Fine pole chucks are better for small parts, but work just fine for larger parts. The inverse is not true for large pole magnetic chuck. The larger space between the poles make holding small parts a tenuois operation. I have ejected small parts from one SG in vo-tech that had a larger gap between the poles.
The learning curve on a surface grinder can and is rough. It is fairly easy to blow up a wheel if you get in a hurry.
The proper wheel of the proper girt and structure can improve the durablity of the wheel.
Which ever SG you buy get a half dozen wheel adapters to mount a variety of wheels on. This way you can have a wheel ready to go, and just swap out the mounted wheel.
Unless you are doing production work, a powerfeed table is not really needed. They are nice but can and do take up a lot more room.
Dan.

To avoid sending small parts into never never land the common practice is to use magnetic transfer parallels or V blocks.

http://www.ebay.com/itm/1-Pair-Matching-magnetic-Transfer-parallels-/262283254007?hash=item3d114cd8f7:g:80oAAOSwPc9Wuh8 o

The blocks allow the chuck to pass more magnetic fields through the part. Each field passing through the block is weaker than the ones in the chuck, but the number of fields created is in most cases the same or greater than those created by a fine pole chuck.

I've been able to grind .032 shim washers down to .015 without sending any of them off to oblivion.

Spin Doctor
02-11-2016, 09:05 AM
Plus standard practice with magnetic parallels (pin or plate type) is to grind them every time you use them. That way you know you have as flat a surface as the grinder can leave.

Mcgyver
02-11-2016, 09:38 AM
I don't have a ton of experience but I have owned one and used several. I have never successfully achieved a commercial grind finish with a small 6x12" grinder. And I have gotten great results from a Taiwanese (Chevalier ) machine with hydraulic feeds. Ball ways are very desirable.


I've a very low wear norton 6x12 (came out of a high school) and you do have to use some care to get what you call a commercial grind. Something bigger and heavier would be nice, but for me isn't justifiable give how much its used and space constraints. A nice feature of the Norton is the ball ways - the surface they roll on is a thin hardened strip sitting on the casting. very smooth.

Finish improvement depends on mechanical condition and balancing. To get that great finish its important to use the original motor. On a quality grinder they are supposed to be better balanced. You also need all slideways and the spindle to be in great shape. To improve finish flood coolant is a must, and its a good idea to balance the wheels. This is where someone will pipe up "you don't need to balance 7" wheels".....maybe not on an industrial machine but they've never chased a perfect finish on a light grinder. I can get good results but still would like better - future plans include a vfd so i can soft start and stop (avoid jarring the wheel as they can move slightly) and some work with diy dynamic balancing. I also added a mitutoyo DRO on the Y axis.....that is a really nice feature especially since the machine (coming out of a school) was metric

projectnut
02-11-2016, 12:25 PM
I've a very low wear norton 6x12 (came out of a high school) and you do have to use some care to get what you call a commercial grind. Something bigger and heavier would be nice, but for me isn't justifiable give how much its used and space constraints. A nice feature of the Norton is the ball ways - the surface they roll on is a thin hardened strip sitting on the casting. very smooth.

Finish improvement depends on mechanical condition and balancing. To get that great finish its important to use the original motor. On a quality grinder they are supposed to be better balanced. You also need all slideways and the spindle to be in great shape. To improve finish flood coolant is a must, and its a good idea to balance the wheels. This is where someone will pipe up "you don't need to balance 7" wheels".....maybe not on an industrial machine but they've never chased a perfect finish on a light grinder. I can get good results but still would like better - future plans include a vfd so i can soft start and stop (avoid jarring the wheel as they can move slightly) and some work with diy dynamic balancing. I also added a mitutoyo DRO on the Y axis.....that is a really nice feature especially since the machine (coming out of a school) was metric

Another key to getting a good finish is to always let the machine "warm up" before making a cut. Over the years I've used a number of different brands of grinders. Every manual I've read and every class I've taken recommends the grinder be turned on and let idle for at least 10 minutes before starting a grind. The idle time allows the bearings and motor to come up to working temperature. Coming up to temp insures all the slop is out of the drive train and bearings. If the machine is new out of the box there will be little or no wear on the components that can transfer to the surface finish. However over time even the most precision bearings wear slightly, and the wear can translate to poor surface finish. Remember we're talking grinding to a finish of .0001 or less. It doesn't take much of a temperature differential to have an influence on that light a cut.

flylo
02-11-2016, 01:19 PM
BF, I have a Browne & Sharp, a Boyer Schultz & a Milwaukee/Delta, too bad you're not closer or I'd donate one to your cause as a peace offering.

Jaakko Fagerlund
02-11-2016, 01:31 PM
Plus standard practice with magnetic parallels (pin or plate type) is to grind them every time you use them. That way you know you have as flat a surface as the grinder can leave.
No, no it's not. If you have a flat table and a flat parallel, it doesn't improve at all by grinding it. You only grind them if you suspect/know they are not parallel/flat. If you need to grind them every time you use them, either the machine is broken or working methods and use of precision tools need to be relearned.

Spin Doctor
02-12-2016, 11:13 AM
The problem comes in when you are using multiple grinders. It never takes much to dust them off. Its the way I was trained and that was by grinder hands with thirty to forty years experience.

Jaakko Fagerlund
02-12-2016, 03:55 PM
The problem comes in when you are using multiple grinders. It never takes much to dust them off. Its the way I was trained and that was by grinder hands with thirty to forty years experience.
What does multiple grinders have to do with a parallel being parallel? If your grinder table is not flat, fix the table or the grinder.

And I don't care if somebody has 30-40 years of experience if they don't know or can't explain the reasons for why things are done as they are. Reminds me of the pot roast story every single time when I hear "been X for Y years and thus I know".

boslab
02-12-2016, 04:46 PM
I was shown that a small fine slip stone after a wipe helps take nibs and impacted grit off the chuck, surprising how it gets stuck there but it does
Then another wipe, you get OCD if your not careful
Mark

Mark Rand
02-12-2016, 06:44 PM
My standard tools are a car windscreen scraper (windshield wiper rubber on a handle) followed by a wipe with a hard Arkansas stone to knock off any burrs. The windscreen wiper is very good at getting the chuck clean when it's wet with coolant.

If you grind dry, I recommend getting a coolant system as soon as you can. They are a great help with dust/grit control.

justanengineer
02-12-2016, 08:02 PM
JMO but one of the most important things to remember with surface grinders is commonly missed bc even among machinists most never move them, only use them - If its got roller or especially ball ways make sure you remove the table before transporting. If you dont and it bounces to any reasonable extent its VERY easy to destroy the accuracy.

Toolguy
02-12-2016, 08:15 PM
Yes - the balls will peen dents into the ways as it bounces around in the truck or trailer on the way home.

Mark Rand
02-12-2016, 08:24 PM
Look for jacking screws on any ball ways. I can't speak for all manufacturers, but my Jones & Shipman 1400 grinder has four jacking screws that will take the load off the Z ball ways for safe moving. Pity I didn't know about them when I got the grinder, but it survived anyway.

jhe.1973
02-16-2016, 01:35 AM
Hi BF,

One detail I didn't see anyone mention is the reliability of the electrical system feeding your building if you are thinking of an electromagnetic chuck. In most big cities and towns in the US, power is stable enough that it is taken for granted.

BUT if, as in our city, the power can cut out at any time even if just a second or two you WILL lose a part that is in contact w/the wheel. If the part is small, not too much of a problem - other that trying to find it!

:D

If the part is tall however (such as grinding the end of something clamped in an angle plate or fixture) the item can tip into the wheel with catastrophic results.

Just another point to consider!

Doozer
02-16-2016, 08:32 AM
Experience does not always equal intelligence.

-D

Black Forest
02-16-2016, 09:08 AM
Hi BF,

One detail I didn't see anyone mention is the reliability of the electrical system feeding your building if you are thinking of an electromagnetic chuck. In most big cities and towns in the US, power is stable enough that it is taken for granted.

BUT if, as in our city, the power can cut out at any time even if just a second or two you WILL lose a part that is in contact w/the wheel. If the part is small, not too much of a problem - other that trying to find it!

:D

If the part is tall however (such as grinding the end of something clamped in an angle plate or fixture) the item can tip into the wheel with catastrophic results.

Just another point to consider!

Thanks for the hint. I do think we are good to go with our electric. In the last ten years we only had the electric go off one time. At least that I am aware of anyway. Not even a flicker in anything that I have noticed.

Black Forest
02-16-2016, 09:16 AM
Experience does not always equal intelligence.

-D

Exactly. It is solely dependent on the individual whether they have continued to learn all those years or if they just repeated lets say one years experience and learning for 30 years. Some time ago I had the son of a friend of mine come to my place and ask if he could weld up a project in my shop. At first I thought he wanted me to weld it up but he just wanted to use my equipment. I asked what process and he said stick would be fine. I don't remember if my MIG was down or not at the time. He grabbed a helmet and struck an arc on a piece of same size scrap material, adjusted the settings some and then welded up his project. He laid down the best beads I have ever seen with a stick. The slag came off in one piece nearly every time. He was a teenager.