Ejector pin grinding/cut off machine?

[Chuck Reamer]

Have any of you made a ejector pin grinder?

I am in need of a pin cutter mostly just for cutting pins to length, they are expensive to purchase. There are a few ideas running around my head, but I am wondering what is a good proven way of doing this.

If you have made something that works good, or know of a decent affordable unit and could throw an idea my way it would be great.

[DaveSki]

A chop saw, surface grinder, v-block, a couple guage blocks, and a pair of mics are all you need. I can normaly whip through 20-30 pins in an hour with this method.
I've used a side wheel in a grinder before but its a little slower.

Pin grinders are nice but I can think of several other things I'd rather have.

[Jim Estes]

I ha ve a fixture that I made years ago, basically a v-block that I can lay down on the chuck or stand up on end. I always cut all my pins off at once, then stand the fixture up and grind the ends to lengh. The cut-off/gind machines that DME sells, only do side grinding, which leaves a rougher finish on the end of the pins, which I never liked. However, for really long pins, 10-14 inches, I have to side grind those anyway.

I worked at a shop once and we made some fixtures to grind pins, they had holes reamed in tso plates to fit the pins, these plates were mounted on a third base plate and one of them could be moved to set the length. I hated those things with a passion, once you got grinding dust in those holes, it was useless.

Jim

[Chuck Reamer]

You still use a surface grinder to finish them to lenght?

Thats the problem, I dont have a surface grinder to work with.

[Jim Estes]

Yes I use the surface grinder, that's how I have always done them and if it aint broke don't fix it. Now, without a surface grinder that could be a problem.

Jim

[Chuck Reamer]

I am thinking a small surface grinder wound be the ticket, I hate not having one around.

Things are kinda difficult when you are still just a start up shop.

[5axisguy]

We have a ejector pin grinder, this thing works slick, it cuts the pin with a cutoff wheel in one direction and grinds the pin to length the other direction, accuracy and repeatability is easy .0005-.001 with a pin up to .375 dia. It takes about 5 seconds a pin if that. Anything bigger I would use the cutoff wheel and surface grinder method.

[Jim Estes]

Chuck,

Have you ever used the grinding wheel in the mill spindle trick? Just make an arbor with a straight shank so that you can hold it in a mill spindle. Then turn the speed up and grind away.

You could also use a tool post grinder in a lathe.

Jim

[Chuck Reamer]

Originally Posted by Jim Estes Chuck, Have you ever used the grinding wheel in the mill spindle trick? Just make an arbor with a straight shank so that you can hold it in a mill spindle. Then turn the speed up and grind away. You could also use a tool post grinder in a lathe. Jim

I had thought about the tool post grinder trick, but I hadn't thought about the mill idea.

Maybe thats the way I should go about this whole thing.

[jetski]

You guys will all think I am nuts. I am in a shop that has limited equipment. I have been a tool maker for 30 years. I have got a feel for grinding pins on a snag grinder and can keep them with in .001 or .002 (here come the nay sayers). You just get use to the feel and know a good touch from a bad touch. It can be done. But you will waste a couple of pins durring the learning process. You would be surprised what you can do when you don't have the right tool handy.

[Chuck Reamer]

Originally Posted by jetski You guys will all think I am nuts. I am in a shop that has limited equipment. I have been a tool maker for 30 years. I have got a feel for grinding pins on a snag grinder and can keep them with in .001 or .002 (here come the nay sayers). You just get use to the feel and know a good touch from a bad touch. It can be done. But you will waste a couple of pins durring the learning process. You would be surprised what you can do when you don't have the right tool handy.

What do you mean by "snag grinder", I have been just using a bench grinder and its working fine for me. I thought hey if I can thin the web on a 1/8" twist drill then grinding a pin flat should be a piece of cake. It turns out that it is a piece of cake, or at least no problems so far.

I am not a nay sayer, your a craftsmen and thats all there is to it.

3 cheers for talent and experience!

[jetski]

Yes what we call a snag grinder is a bench or pedistal grinder. The Great White North? You guys are the best in Canada. I did a trade show in Edmonton several years back. Nicest place with the friendliest people on the earth. Glad to see the Loonie and the Toonie doing well. Back to the grinder think we have used the v-block and a stop, cut off wheel on a surface grinder. Hey the trick on the snag grinder is to learn on larger dia. pins at first and then slowly work your way down to the .062 dia. ones. I get those with in .003 and stone them if they are critical. You would also be amazed at what you can do with a dremel tool. Have fun.