Boyar-Schultz 612

ddickey

H-M Supporter - Gold Member
H-M Supporter Gold Member
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Where does this grinder fit in as far as quality and desirability?
 
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...
 
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?
 
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.
 
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.
 
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!
 
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?
 
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.
 
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.
 
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