# Belt Grinder - From Bob Warfields disk sander



## cfellows (Feb 13, 2008)

Bob,

Here are some pics. I built this from a 1hp, 3425rpm pump motor. The pulleys are welded up from 4.5" pipe so at 3425 rpm I get 4000 surface feet per minute. It removes skin really fast! The column is made of two pieces of telescoping square tubing, with a spring in the middle to keep the belt tight. A large piece of angle iron is welded to the bottom column and bolts directly to the motor. The platen behind the belt is milled from a piece of Angle Iron. I've had to remove that recently and mill it flat again. It became troughed in the center.

This is probably one of the most used tools in my shop. I've already had to replace the motor bearings once since I built the sander about 10 years ago.

You can also see my carbide grinder in a couple of the pictures. That's made from a 1/2hp pump motor. The shield is made from a pie shaped piece of an aluminum frying pan!

Chuck


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## BobWarfield (Feb 13, 2008)

That's a really nice belt grinder Chuck!

Did you crown the pulleys? Curious how you went about that. Is the spring in the column such that its really easy to swap belts?

I'm planning to clone the Beaumont Metal Works KMG Grinder: http://www.beaumontmetalworks.com/grinder.html

It's very versatile. I've got a VFD and 2.5 HP motor, so it'll be capable of shaving some metal. I want to try my hand at knife making, and this design is popular with that crowd.

I'm not surprised to hear you use it so much. I can already see how useful the disc sander will be. Watching some of the knife making vids on YouTube, you can see the belt grinders can really move some metal fast and leave a decent finish too.

Thanks for posting your pix. 

BTW, for those who find various belt sanders interesting, I have a bunch of pix of a fellow from Brazil who has several designs, including a homemade belt surface grinder. See this page at the top: http://www.cnccookbook.com/CCHallOfFame2.html

Best,

BW


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## Bernd (Feb 13, 2008)

BobWarfield  said:
			
		

> BTW, for those who find various belt sanders interesting, I have a bunch of pix of a fellow from Brazil who has several designs, including a homemade belt surface grinder. See this page at the top: http://www.cnccookbook.com/CCHallOfFame2.html
> 
> Best,
> 
> BW



Boy that's one nice looking shop. That belt sander was build almost like a surface grinder. Very neat. I like the way the whole thing was powered, especially the table.


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## cfellows (Feb 13, 2008)

BobWarfield  said:
			
		

> That's a really nice belt grinder Chuck!
> 
> Did you crown the pulleys? Curious how you went about that. Is the spring in the column such that its really easy to swap belts?



Bob, I did crown the pulleys, but I don't remember for sure how I did it. As I recall, I used the compound on my lathe set a a really shallow angle to shave off a a third on each side, then used a grinder and file to round them off a bit. The spring in the column is pretty stiff. To change the belt, I have to press down pretty hard on the top pulley then put sideways pressure on so friction will hold it down while I slide off the old belt. Then I do it again to put on the new one. Not really all that hard considering I don't change the belt very often.

I really do like the Beaumont style grinder with interchangeable platens. It makes for a much more versatile grinder. Also, the 72" sanding belt is supposed to run cooler than a 48" belt. However, the 72" belts are more expensive. Still I have seriously considered building one.

Another belt grinder design that I like is the one pictured below. It is great for doing contour grinding.


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## BobWarfield (Feb 13, 2008)

Yep, one of the things I want to try for on the belt grinder is the ability to flip it to lie horizontally or vertically. I also came across a really nice rest for the grinder that I will probably borrow from.

Lots of planning to do on that project. Not sure if I'll dive right into it or try something else first. There are many open cans of worms in my shop to choose from!

Best,

BW


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## Hal (Feb 13, 2008)

Very nice job on the grinders. 

Do you have a pictue handy of the grinding rest.

Hal


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## Stan (Feb 13, 2008)

Bob: I used a similar motor to build a belt sander and you should be aware that the motor will suck the metal you grind off into the motor. If you are not going to run it for prolonged periods, you can seal of the vent holes completely. Otherwise, devise some kind of shield to keep metal particles out of the motor.


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## BobWarfield (Feb 13, 2008)

Stan, I assume you're directing your comment to Chuck. He seems to have kept his going for 10 years, albeit with a bearing rebuild, so I guess he has a handle on it. The motor on my disc sander is completely sealed. 

FWIW, I have had success using ScotchBrite pads and hot glue to filter the vents on motors that are not sealed. It's ugly as sin, but it has worked well on my DC treadmill motor conversion on my lathe:






Probably not the best idea for a grinder as the particulates will be smaller, but perhaps a finer filter would be acceptable.

Hal, that grinding rest is in this thread:

http://www.bladeforums.com/forums/showthread.php?t=466024

A rest like that, coupled with the flexible KMG-style arm system (many attachments for which are depicted in that thread) and the ability to operate the belt grinder either upright or in a horizontal mode seems like it would offer one heck of a lot of flexibility. 

I'll keep ya'll posted!

Best,

BW


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## cfellows (Feb 13, 2008)

Actually, now that I think about it, I replaced a bearing in the top pulley, not the motor. The cooling air is drawn in the back of the motor and exhausted out the openings on the side near the front. That's probably why I've never had a problem with grit and dust getting into the motor.

Chuck


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