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JoeCB
09-10-2010, 06:46 PM
Is there anyway to improvise a centerless grinder set up? Maybe some sort of rolling fixture on a surface grinder? I may need to fab a couple dozen small cylindrerical parts... sort of like hydraulic valve spools. These would be hard, about 5/16 dia X 2 inch long close tolerance and no centers. I likley could not justify the set-up cost at a speciality shop.
Joe B

DR
09-10-2010, 07:18 PM
There are at least two centerless grinding attachments that were available in the past to do what you want. Can't think of the brand names right now.

I had one of the more popular ones, but sold it because of the hassle of setup. It was easier for me to send the parts out. They're time consuming enough to setup that you'd almost want to dedicate a surface grinder permanently to it. When I had a dozen parts to run, I'd ruin as many in the setup phase.

The attachments are not cheap by anyone's standards. Unless you find one at auction like I did.

KiddZimaHater
09-10-2010, 08:04 PM
5/16 dia X 2 inch long close tolerance and no centers
Have you thought about using a spin-jig, or a Harig Grind-All on your surface grinder?
I used-to grind ejector pins all the time with these.

http://www.penntoolco.com/images/catalog/1464.gif

http://metalworking.mscdirect.com/ProductImages/0945055-11.jpg

squirrel
09-10-2010, 08:25 PM
There are at least two centerless grinding attachments that were available in the past to do what you want. Can't think of the brand names right now.

I had one of the more popular ones, but sold it because of the hassle of setup. It was easier for me to send the parts out. They're time consuming enough to setup that you'd almost want to dedicate a surface grinder permanently to it. When I had a dozen parts to run, I'd ruin as many in the setup phase.

The attachments are not cheap by anyone's standards. Unless you find one at auction like I did.
DedTru, extremely nice, very expensive new. Not much need for them any more you can buy one for under $2000

doctor demo
09-11-2010, 12:23 AM
I bought a horror fight lathe to put on the surface grinder to do a run of small roller shafts a while back, it worked out well.
I can't remember if I posted any pics. I can't find it now.

Steve

TGTool
09-11-2010, 12:51 AM
Is there anyway to improvise a centerless grinder set up? Maybe some sort of rolling fixture on a surface grinder? I may need to fab a couple dozen small cylindrerical parts... sort of like hydraulic valve spools. These would be hard, about 5/16 dia X 2 inch long close tolerance and no centers. I likley could not justify the set-up cost at a speciality shop.
Joe B

Can you cut off centers afterwards and grind the ends or does the design not lend itself to that? If so it could give you more options. I presume you have a surface grinder now but not a cylindrical grinder. And don't forget that you can use an external hone or lap also to creep up on tolerances.

Rustybolt
09-11-2010, 11:16 AM
squirrel has it.
Find a picture of a dedtru and see if you can copy it.

easymike29
09-11-2010, 11:29 AM
If the blanks are already to length with no centers you can epoxy or even soft solder false centers and then grind. Otherwise machine the blanks as already mentioned with removable centers.

Gene