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Boyar-Schultz 612

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ddickey

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#1
Where does this grinder fit in as far as quality and desirability?
 

Bob Korves

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#2
Boyar-Schultz is the Chevrolet of surface grinders. Lots of them were made and they do the job, good machines. Boyar-Schultz has long been out of business, so the used machines we look at are a mixed bag of careful use, abuse, lots of wear, or very little wear. A surface grinder needs to be carefully inspected, including under power, to determine it's condition. Having someone along with you who really knows surface grinders is a huge asset when you go shopping. The difference between a nice used machine and scrap metal is usually not noticeable at all to a newbie.

The other issue is that surface grinders used in a commercial setting are often run until they are used up, then rebuilt if it makes financial sense. If not, they are scrapped or sold to clueless newbies at a higher price.

There is no commercial parts support at all for most used surface grinders, and when parts are available, they are often quite expensive. Commercial spindle repair is quite expensive, if available at all for old machines. If buying one, know how to inspect it, and consider your skills and limitations before bringing it home. Verify all claims...
 

ddickey

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#3
I'll definitely make sure it's in good shape.
For $1800 asking price it should be. One hub included so that is a slight disappointment. I'm only shopping and in no hurry as I have a small surface grinder at the moment but would like something larger.
So if Boyar-Schultz are the Chevy's what are the Caddy's?
 

Bob Korves

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#4
Mitsui, Parker Majestic, Okamoto, Brown & Sharpe Micromaster, Harig, Chevalier, Reid, for home shop size machines, probably missed some. Then, too, some people like Mercedes better than Caddy's. In the used market, any brand can be junk, and any brand can be quite usable, depending on condition, condition, and condition. Some have the handles on the opposite sides, and things like that are personal preference. Since you have a surface grinder already, you can take your time and be a whole lot more picky.
 

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#5
Bob's completely right! I got my Brown and Sharpe 612 at a good price, but not before they ran it a year without lubrication. Lucky me, they got a CNC grinder to replace it before it was all used up. It needs tender loving care, but it has good accuracy. For my limited use, I'll never wear it out.

The way I inspected the grinder is that I brought a 1" X 2" X 3/4" coupon of hardened 4140 (SPS) steel, and ground it both sides and measured it. The perfect test is a 5 block test, but most people don't have the patience to let you do that. The piece was withing 2 tenths with no lubrication or coolant.
To me, that means the bones of the machine were OK - I of course looked at the lead screws, felt the backlash, etc

BUT if the bearings are noisy, just walk away. It takes a very good millwright to rebuld the spindle and get it right. Easier to pass and buy a machine in better condition.

For $1800, I'd only buy it if it has been checked over by a good grinder hand, and passes the 5 block test.
 

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#6
Check for backlash on the in and out feedscrew. It is the most critical part on the machine. If there is too much slop when feeding the table in, not left to right, then you have to make a choice. The feedscrew for the head is always under load so backlash there is not an issue, nor the left/right feeds. We are scrapping out our B&S unit shortly as those lead screws are Unobtainium!
 

vtcnc

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#7
5 block test? Is that a block on each corner and one in the center of the chuck?

I imagine that even if that passed the thickness test, the machine could still be out of whack, i.e., bad spindle. Am I understanding this correctly?
 

Cadillac

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#8
5 block test? Is that a block on each corner and one in the center of the chuck?

I imagine that even if that passed the thickness test, the machine could still be out of whack, i.e., bad spindle. Am I understanding this correctly?
Yes your right. It gives you a good indication of the table and saddle.
 

Bob Korves

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5 block test? Is that a block on each corner and one in the center of the chuck?

I imagine that even if that passed the thickness test, the machine could still be out of whack, i.e., bad spindle. Am I understanding this correctly?
The five block test is to see if the machine and chuck as configured will grind five blocks to the same thickness in five maximum spread locations on the chuck.

None of that is about surface finish from a bad spindle. Only one block is needed to see that problem.
 

Bob Korves

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#10
If there is too much slop when feeding the table in, not left to right, then you have to make a choice.
Pierre, please define "too much slop" and tell us what problems that causes.
 

pdentrem

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#11
When moving the part in and out and trying to hit against a shoulder, one does not need to be fighting a ton of backlash. Our current B&S has been causing problems in making tooling as the table moves in and out uncontrolled while feeding from left to right. Gibs are set tight but to no avail. We took a look at the leadscrew and the center section is so worn that the thread is now more like a standard 60 degree instead of acme. Near 0.050”! The brass nut has nothing left to give as the adjustment will not allow smooth action from end to end of the leadscrew. We have been searching for a less worn or NOS but there is nothing out there. We have looked at replacing with a ball screw which would work as the lead screw is protected fairly well from the grinding dust. It is just more economical to find a newer or new machine.

The magnetic chuck has to be ground flat if it has been removed and put back, otherwise it may not hold size across the whole surface.
 

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#12
There are a bunch of things that work together to get accurate grinding out of any SG. The ways have to be tight, the saddle has to move back and forth without much sideways slop, the spindle has to be smooth, the motor has to run without too much vibration (and add many more to this).

On the minus side, there are many things that could destroy accuracy. a non-flat chuck. burs on the chuck,. grinding dust under the part. Poorly dressed wheel.the wrong hardness of wheel for the material. Ohmigosh - add many more here...)

Now all that being said, most grinders can easily achieve a half-thousands of an inch easily, even in inexperienced hands. The closer your tolerance, the harder it is to achieve. To hold a part to 20 millionths, for example, takes a lot of fussing by a very experienced hand. (not me) :(
 

Janderso

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#13
I know nothing about a surface grinder.
They work in an abrasive environment from day one, it’s hard for me to imagine a machine that wasn’t worn out after considerable use.
If I ever find one, I would want someone that knows what to look for to accompany me.
There are some Boyar Schultz grinders around, I was not aware parts are not available.
Are there any, “safe” brands to consider in the event parts are required?
I can see how new Taiwan made grinders may be a viable option.
 

Bob Korves

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#14
When moving the part in and out and trying to hit against a shoulder, one does not need to be fighting a ton of backlash. Our current B&S has been causing problems in making tooling as the table moves in and out uncontrolled while feeding from left to right. Gibs are set tight but to no avail. We took a look at the leadscrew and the center section is so worn that the thread is now more like a standard 60 degree instead of acme. Near 0.050”! The brass nut has nothing left to give as the adjustment will not allow smooth action from end to end of the leadscrew. We have been searching for a less worn or NOS but there is nothing out there. We have looked at replacing with a ball screw which would work as the lead screw is protected fairly well from the grinding dust. It is just more economical to find a newer or new machine.

The magnetic chuck has to be ground flat if it has been removed and put back, otherwise it may not hold size across the whole surface.
Thanks for the reply, Pierre. My B&S 2L from 1946 likely has the original Z axis (carriage toward and away from the column) lead screw. It looked really nice after carefully cleaning it and the nut when putting it back into service. Backlash in that axis is .040+" on the .250"/rev dial. That does not seem to cause any problems so far, though I have done little work against a shoulder, and that work was light. What should I be looking for?
 

Bob Korves

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#15
I know nothing about a surface grinder.
They work in an abrasive environment from day one, it’s hard for me to imagine a machine that wasn’t worn out after considerable use.
If I ever find one, I would want someone that knows what to look for to accompany me.
There are some Boyar Schultz grinders around, I was not aware parts are not available.
Are there any, “safe” brands to consider in the event parts are required?
I can see how new Taiwan made grinders may be a viable option.
Parts for surface grinders from defunct companies are rarely available new, and used parts off another machine may be better or worse than what you have already. Getting parts for even newer Chinese machines is often a crap shoot, often taking lots of time and frustration, the replacement parts not fitting at all or an incorrect part finally delivered. More respected Asian brands like Jet and others (mostly Taiwan made) that have been in business for decades seem to do a much better of servicing what they sell, but their parts are not cheap, and can still take time and effort to get the correct part in your hands. And obsolete machines also often have obsolete parts, even with the best companies, a business reality. But, we are machinists and often not just parts changers. With sometimes significant time and effort, we can make many of the parts we need. Machine tool reconditioning in our shops is quite possible, but does have a significant learning curve to be able to completely rehab a machine to working, like new, or even better standards. Some people love to rehab old machines, other just want to make parts on them. Look yourself in the mirror and have a sober conversation with yourself on what you hopefully might be able to achieve and what you might _actually_ achieve. Be honest with yourself. I see lots of carcasses of old machines sitting around partially disassembled and gathering dust in hobby machinist shops. "Some day soon" can be a long time -- or never...
 

wlburton

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#16
I'll definitely make sure it's in good shape.
For $1800 asking price it should be. One hub included so that is a slight disappointment. I'm only shopping and in no hurry as I have a small surface grinder at the moment but would like something larger.
So if Boyar-Schultz are the Chevy's what are the Caddy's?
If you ever do buy a larger one and decide to sell the Sanford let me know.
Bill
 

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#17
Are there any, “safe” brands to consider in the event parts are required?
I can see how new Taiwan made grinders may be a viable option.
A quick note professional firms like Suburban Tool tend to have a lot of Reid and Chevalier grinders, but prefer to rebuild them rather than buy new. A gear manufacturer near me has bought all the very old 24" shapers it can find, in order to rough gears quickly. There's a reason for that. the older castings are 'real' Meahinite (I think I spelt it wrong - sigh) instead of the poorer quality cast iron available today. Those old machines can be rebuilt almost forever, and hold accuracy well when used right.

So an obsolete grinder in today's shop might very well do anything you will want to do in your lifetime. It is just there are a few bad apples that will claim they are great when they are not rebuildable. Buying new is expensive (more than double the cost of a good used one) and is almost as risky. I would be wary of the current crop of cheaper grinders - they weigh half to a third of the old iron, so they are less rigid and have far less 'reaction mass'. That mass helps to reduce the effect of vibration and impact of the wheel itself. Lighter machines in general have worse finish and harder-to-achieve accuracy.

Take heart - there is a grinder out there for you! Keep looking. Another strategy is to visit a shop a week, and ask the forman if they have a grinder that is not being used. Mine came from a shop where it it had been 'sidelined' in favor of a CNC grinder. I paid pretty good cash for it, but I'm very happy it's mine.
 

Technical Ted

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#19
I recently picked up a B&S 2B surface grinder that was built ~1935. It had been rebuilt by Pope with an Excell-o cartridge spindle at some point. Looked like a POS when I brought it home. Paid $200 for it, basically scrap value since it weighed over 1400 lbs. Came with a B&S magnetic chuck, one spindle adapter and two wheels (one brand new). I tore it down for complete cleaning. The spindle was 440 V only so I modified it for a single phase 1-HP motor.

After dusting off the chuck it did the 5 block test and checked them on my surface plate with a tenth's indicator. All were within 0.00015 of each other. Plenty good enough for anything I would need!

So, sometimes you can find a diamond in the rough!

Good luck in your search,
Ted
 

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#20
Great find!
 

Grandpop

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#21
I am not trying to disrespect anyone. I know lots of folks swear by the 5 block test, but it does seem to really tell me anything. Typically the table/saddle are worn near center of travel but not hardly at all on ends of travel, such that the machine is grinding a large radius. Have done the 5 blocks on such machines, and the blocks are the same size. Seems like all the 5 blocks tell you is that the chuck was ground such that it is moving in exact same motion as the table. All the blocks the same size but table still grinding in a large radius. On such a machine you can grind shorter parallel parts, but can't grind anything long straight/flat.

I've always taken a good straight edge and 2 dowel pins. Place the dowels on ends of the chuck, turn on magnet, place straight edge over the dowels. mount indicator on spindle and indicate top of the straight edge while moving table slow and normal speeds. You will see lift at the ends if center of table is worn, or even rocking when you reverse direction.

I don't get too worried about backlash as long as less than about .040. Much more than that you don't have any flats left on the acme screw between threads and it wears fast. All the wheel graduations are telling you is where you last were, so more worried about repeating back to same point, which a worn screw with backlash will do. If you are trying to plunge a second slot 3.0000 over just by using the screw you are not going to have good results on most grinders, even when you have a good DRO.

I personally loved the Mitsui grinders when I ran them full time, but they are expensive used. I could not find one close to me for less than $5k, but I did find a filthy Boyar Shultz 20 miles from my house for $500 with .030 backlash and a bit of a lift in the table. It works good for what I do with it at home.
 

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#22
The 5 block test is just one of many tests, and the most popular. For a thorough check out you can take a pair of parallels and grind then along and across the chuck. The results will tell you a lot about the X and Y ways. Most vendors won't let you do that much grinding on their machine, however.
 

C-Bag

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#23
Thanks to all for your input. Very enlightening on several fronts and sobering too. My TAS has had me jones'n for a SG for a while and conversations like this have made me pump the brakes as two likely candidates have popped up locally.

Both have supposedly (you know how CL is) not been used for production. Appear to be in good shape and both Tiawan made. Both companies are still around. One is a 6x12, the other 8x18. The small one has a "new" mag chuck and is what I would call a hobby machine with no accessories except a heavy duty stand and has dropped into what I call an acceptable price range and appears to be the same as the bottom of the line Grizzley SG so parts would be available I would think. It's also single phase 110/220. But for twice as much ($1200)the 8x18 has accessories, stacks of wheels(diamond included) but is 3ph, which some say is the only way to go. But I have no experience with VFD's.

This seems to happen often and has made me a deer in the headlights. Bob's "look yourself in the mirror" is a big part of that too as I have no specific project in mind. Only the idea it would cure my need for that next level of accuracy. But this discussion has put that in perspective.
 

ddickey

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#24
The 5 block test is just one of many tests, and the most popular. For a thorough check out you can take a pair of parallels and grind then along and across the chuck. The results will tell you a lot about the X and Y ways. Most vendors won't let you do that much grinding on their machine, however.
Using a parallel with a DTI would tell you the same as grinding, wouldn't it?
My little Sanford is accurate only with it's 3x5 chuck. Outside of that forget it.
 

C-Bag

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#25
It took some thought for me to get what Grandpop was getting at. But the long parallel across the X of the chuck and going through the X travel with DTI on the head through the travel would show the shallow arc of a worn ways by a dip in the middle and rises at the ends. I get I repeated him but that is the meat, that you are measuring the whole length. Now how, if the head remains steady it could not show the center middle block as being thicker is something my noob brain can't quite comprehend. But I could run his test a lot quicker than the 5 block when doing the buying inspection. The 5 block would have the advantage of taking a while and therefore a good way to know if the spindle developes noise after it warms up. All tests are good IMHO.
 

Technical Ted

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#26
Because after dusting the chuck it is ground with a hollow in the center and the middle block will be in that hollow. All blocks will be ground parallel with the hollow in the chuck and therefore the same thickness will result. So, the parallel spanning the chuck will show a gap between the bottom of the parallel and the top of the chuck in the center (if a hollow exists).

You could also grind something long enough to span the chuck that is too thick to be drawn down in the center by the magnet (if you have a hollow on your machine) and then measure the piece on a surface plate with a tenths indicator and it should show that the ground piece is not flat, but thicker on the ends with the same hollow (low spot) in its' center.

Ted
 

C-Bag

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#27
But I would think if there is wear in the ways, dusting the mag chuck would make it flat because it is reference to the head. It's staying stationary and the table if it does have wear and making an arc would compensate for the wear arc effectively leaving the chuck thicker in the middle and thinner at the ends. So would this would show as a hump in the middle with a straight edge laying on it?

Also, I've read here in another thread that a chuck should be ground in with coolant? What if the grinder has no coolant tub are whatever you call it?
 

Technical Ted

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#28
Dusting the chuck will only make the chuck flat if the ways are flat. All it really does is make the distance from the chuck to the grinding wheel the same, but if the ways aren't moving the chuck in a flat plane the chuck will follow the same path as the worn ways and will not be flat. This is true with a mill machine as well, but there it is more forgiving since you're probably not working within tenths of an inch.

It helps me when I exaggerate things... Think if the ways are like a roller coaster, going up and down. So now your chuck would be traveling up and down with it and as you dust it the grinding wheel will maintain a constant distance between it and the chuck because the spindle is fixed in space. So, it grinds more off the chuck when the ways go up and less when they go down. But, as you can see, the top of the chuck would be a roller coaster ride as well since it is going up and down with the travel on the ways.

Maybe someone else can jump in and help explain it another way that makes more sense.

Ted
 

Bob Korves

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#29
Dusting the chuck will only make the chuck flat if the ways are flat.
Correct! And the same can be said about the work produced on the machine.

The common problem with both milling machines and surface grinders is that traversing the table puts more pressure on the ends of the ways when the table is near the ends. The table overhangs the ends of the ways. As wear accumulates, this causes a gradual changing of the ways from flat to curved, high in the middle. Assuming that the wear is evenly increased from center to both ends (not exactly true in real life), then as the table goes under the spindle, an indicator will give a steady reading, no movement at all. That does not also mean the work is being ground or milled flat, all it tells you is that the wear is even along the length of the curve. The way to find out the real truth is to machine or grind a piece that is the maximum length that the table will traverse, and then check it for flatness on a surface plate. You may be quite surprised, especially if the indicator under the spindle showed no movement.

The issue can be addressed by using a grinder that does not have the same issue (it has KNOWN flat ways) to grind the worn grinder, or scraping the ways in while referencing them to a known accurate surface plate.
 
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Dabbler

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#30
OK, I'm going to try, but it is very hard for me to explain. Because the chuck is ground on the machine with the "bad" ways, The DTI on the chuck will always read the same, even if the ways are worn. The tolerances here are small enough that even if you owned and brought a 12" parallel it is very hard to see the dip or roll off of the chuck under the parallel. You can use the 'wiggle' test on the parallel to see if the chuck is flat, but it won't tell you how much it is out, if it is. - That is, you wiggle one end of the parallel, then the other and both fulcrum points should show 1/3-2/3 in each direction if the chuck is as flat as the parallel

Now this is where it gets interesting: if the 'banana' of the ways is symmetric, then measuring a parallel on dowel pins won't show much of the actual discrepancy - it would take a lot of measurements to figure out the actual curvature of the ways. It can be done, with time and patience.

Here's what I learned from my toolmaker friend. There are about 6 primary points of inaccuracy that can develop in a SG (I don't think he ever enumerated them for me, but accept there is a lot going on) Some of the things are X ways low or high in one region; Y ways tilted to the direction of movement; The Z lead screw and ways completely worn out, and therefore the wheel 'bobs' on the surface; The bearings are shot in the spindle and the wheel lifts when it engages on the surface, making the surface inconsistent; The roller bearings (if any) are worn so that the table is inconsistently supported; [These are off the top of my head, but there are a lot more...]

The only *reliable* way to check out a SG is by grinding something, not just measuring something. For instance, if the ways are worn out in the center and the chuck is reground, the 5 block test will tell a different story than if the ends were low and the center is high. This might be missed by doing the dowel pin method if the hollow is small enough. Some machines spend their entire life grinding 2" in X and Y... You can also miss a small hollow with the 5 block test!

Now If you grind a parallel along the X axis, and one along the Y axis, it is a shortcut to the 5 block test, but you can find out if the ends are low or high, or if the Vee way is lower/higher than the flat way.... After grinding you take an accurate micrometer and measure the ends and center of each parallel. If all the measurements are the same, then you should be able to do good work on the grinder. If not, then walk away, unless you know how to rebuild machines and *really* want to.

I would NEVER buy a SG that I haven't spun up and at least ground a hardened coupon on it. You can learn a lot about it from that test, and without it, you are playing the lottery for your money. Even if it is really cheap, it might be a gem or totally worthless.

That being said, if you like rebuilding machines, a SG is almost always rebuildable, but not always worth all the work and expense - a different machine (which might be even cheaper) could require much less or no work to run accurately.....

I hope this helps clarify. No 'test' is definitive - it is just a way to eliminate obvious duds from possible gems. There are as many tests as there are opinions, these are just mine...:geek:
 
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