The Surface Grinder Needs Help

Chris Crawford

Chris Crawford

Joined
Apr 14, 2001
Messages
380
I've recently acquired a surface grinder that runs 2x72" belts. The problem that I'm having is that the surface wheel is not true. The wheel was an 8 inch Grizzly wheel that has had the rubber turned off. While the wheel has no rubber on it, I have my suspicions about what method was used. I don't think the guy who turned the wheel did too good of a job on it because it is full of deep scratches and groves.

So, when the wheel turns, there is a high spot on it that strikes the material being ground before the rest of the wheel can make contact with it. What makes it worse is that after so many rotations, the joint in the belt hits at the same time as the high spot causing the metal to slide on the magnetic chuck.

I don't know if the problem is that wheel is not true, the shaft is not true, or if the bore in the wheel is over sized causing the wheel to not be centered. I could take the wheel off and have it machined back true, but if the bore is not the right size or the shaft is not true I will still have the same problem.

So I have this idea for a solution and I wanted to run it by you guys to see if it would work, or what other suggestions you may have. I know you can true up a stone wheel on a surface grinder by running it across a diamond dressing stone mounted to the table of the surface grinder. Do you think I could do something similar using a vice and a lathe bit? My idea is to mount the lathe bit in a milling vice and secure the milling vice to the surface grinder's table. Then turn the grinder on, run the wheel down until it touches the bit, and move the table back and fourth cutting away at the wheel.

Would this idea work? What problems may I run into, and what other things should I consider?

Thanks in advance for the help. -chris

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Chris Crawford Knives

 
Your idea will probably work, but be careful. I would want a hard rubber wheel.
The belt splice is going to be more of a problem with a metal than with a rubber wheel, some guys scape the grit off of the splice and this seems to help alot.

Don Hanson lll
 
Chris, your idea should work if the problem is on the wheel itself. If it is because of slop anywhere as in the shaft to wheel fit, it won't help at all and might make it worse.

I agree with Don, the belt joint is a bigger problem and a hard rubber wheel may well solve the issue altogether.
 
Hi Chris,

First thing I would do is remove the wheel and with an acurate dial indicator do a run-out on the shaft. Make the nessasary adjustments. Once the shaft is dealt with then I'd start on the wheel. An easier way to true the wheel up may be to mount a piece of sand paper to the magnetic chuck and slowly bring the wheel down to the chuck. Cycle the table back and forth while lowering the wheel down a bit at a time. Do this until the wheel is concentric.
 
Chris,

Good advice above. Mine is to check the spindle for run-out like Art suggests, but then ditch the contact wheel and buy a new one from Rob Frink. Try to get 100 durometer of you can. I am assuming your motor spins at 3450 rpms, and if that is true then your idea for truing your own wheel is going to present a ticklish situation. an 8" diameter wheel spinning at 3450 is way too fast - even if it was properly mounted in a lathe. My advice is to have the contact wheel turned and trued on a lathe, and then recovered at Contact Rubber Co. or maybe Formtech. A place I use everyday for recovering printing rollers here at work is The Tripp Company. Their number is 800.874.7726, and ask for Jack Kauflyn or Mike Tripp. Tell them I sent you (Jeff Higgins at Printegra).
 
Chris, I strongly recommend the wheels from Bertie Reitveld for this purpose. It will take you a few weeks to get them as Bertie makes them to order. Chris and Anne Reeve handle his financial affairs here in America so you can transfer the funds to them and Bertie will ship the wheels to your address. A lot of makers use Bertie's wheels for this purpose. I use them and believe Nick Wheeler and Ed Caffrey do as well.
 
Thanks for the advice guys. I know that I'm going to have to do something because there is no way I can use it like it is and expect to have satisfying results.

Is it a good idea to go with a hard surface such as the metal wheel itself, or is a rubber type wheel better. I had heard that a rubber covered wheel would round your edges too much.

One thing I want to do is surface folder parts once they are finished, so I would want the edges of the parts sharp and square.

Thanks -chris
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Chris Crawford Knives

 
Hi Chris,

I have used both the belt equiped and wheel equiped surface grinders. The belts are great for quick removal of material. We used a belt rig at Devins for finishing bar stock. We started with a rubber wheel which did cause rounding. We also had a short belt life. Devin has since switched to a hard steel contact wheel and has longer belt life because the steel helps keep the belt broken down exposing fresh cutting surface.

In my own shop I have a stone designed for stailess steel. Using a stone is a lot slower then a belt. I'm very picky when it comes to the tolerances in my folders and the only way to get what I want is to use a stone. I personally would chuck the belt for finishing folder parts and switch to a grinding stone. There will be some that disagree with me. The only way your going to decide is to try both and see what works for you.
 
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