# Belt grinder tracking



## Artfuldodger (Jan 28, 2012)

Hello, I just made a belt grinder. It is powered by a 3400rpm 1.5hp, 110v motor. It looks kinda like this one in this link.
http://www.cnccookbook.com/img/OthersProjects/Knives/grinders/EmIsleBeltGrinder2.jpg
I'm having trouble getting the belt to track. It will eventually have a 2"x60" or a 2.5"X60" belt on it. Right now i have a 1.5" belt on it. The 4 wheels are all the same size, 2.5" crowned. Will the wider belt track better? All four pulleys are crowned, possibly 10 degrees. Is it ok for all the pulleys to be crowned? Is 10 degrees too much.  These pulleys were found in a junk barn and not made for a sanding belt. I haven't researched this much yet. I found one forum where they argued whether the belt would go to the loose side or tight side of pulleys. It seems like it would tract to the loose side but physics says it will track to the tight side. I do have a tracking pulley that goes up/down. I may need to move my drive pulley left/right.


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## John I. Shore (Jan 29, 2012)

Looks from the pic that the tracking is done on the top wheel.  The canting of that wheel should drive the tracking of the belt.  Time has shown that flat wheels work better than having them all crowned, you'll really notice a difference on the contact wheel unless all you do is flat grinding.  
You'll like the machine even more if you can get you a good 2HP Variable speed motor, you will have more control and be able to do a lot more with your grinder.  Then I would also suggest that you increase the circumference of the wheel geometry to take a longer belt.  We use a lot of 72" belts but we also use a bunch of 132" belts.  The longer the belt the cooler the grind, you will build up a lot of heat really quick with the short, fast running belts. Good luck with it, hope this helps.

John I.


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## IFLY4U (Jan 29, 2012)

A concern that you may want to think about is the speed of your motor. 3400 RPM may lead you to ruining some good steel and becoming very frustrated. Most of the grinders that I have seen and the KMG that I use have a motor RPM in the 1740 / 1750 range. I use 2 three step pulleys to adjust my speed and really wish that I had a variable speed so that I could run it even slower for detailed work. The design is similar to a KMG and the tracking pulley is the top rear pulley and John is correct on how it should adjust. 

Just my 2 cents worth from a guy that can't get all of his grind lines out.

Gary


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## Artfuldodger (Jan 29, 2012)

I was going to initially use 72" belts but it just didn't work out that way.  My top wheel does the tracking. I might have to decrown the other wheels. I would like to go the VFD & 3 Phase motor route eventually. I did notice most belt grinders use 1750 rpm motors but a lot use 3400 rpm also. Certain models of Burr King, Hammond, Grizzly, KMG, & Delta for example. The motor i have is for a Delta Belt sander. Mainly using it because that what i have for free. Could I vary the pulleys to slow it down? I guess the belt speed FPS is what's really important. Wouldn't know how to figure that except with a strobe meter. I do have a pulley speed calculator link. This guy says his KMG has a 3400 motor. He does have a VFD on it though.
http://www.burgessknives.com/8201/index.html


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## Anvil Head (Jan 30, 2012)

10 deg. seems pretty "touchy" for adjusting tracking. Most of the idlers I've looked at and the one I use is probably more like 2 deg.
Without seeing what you have built, it's hard to troubleshoot these issues. 
Having "loose" pulleys will always present a precision problem in belt tracking. If built similar to the one in your link, expanding to 72" shouldn't be all that big a problem with a little thinking. Plus, 72's are way more "off the shelf" available.
Would definitely step the speed down from the motor, matter of pulley configuration. What you are looking for is belt speed control not just rpms. Go to KNF forums or Bladeforums and do a search, there are tables for figuring this out.

It's either that or learn to use a hammer with more precision. 
Wifey says...."If he can't fix it with a hammer, it's got to be an electrical problem!"


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## Artfuldodger (Jan 30, 2012)

Yeah i think my wheels have too much crown. I found them in an old bldg. They were not made for a belt grinder. I don't think they are 10 deg. maybe 5-6. I'll measure them with a protractor but it's still  more than the 2 deg belt sander wheels. They are aluminium.I could extend the rectangle channel my wheel is on to use 72" belts since that is the standard length.


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## Bigtimber (Jan 30, 2012)

I have one I built simular.....you would want first off I would think to extend the "key stock" removable tooling arm to get a 2 x 72 belt length....those belts would be far easier to get. I run a 1750 2 hp motor....but tracking with a faster motor I don't think would be a big issue...you just might find it too fast once you get to grinding. Pulley size  one the motor will make a difference there as well. The overall tracking....well my front two wheels are flat, the crowned wheels are on the main drive pulley and the tracking pulley. Both of those were bought through KMG. You might want to call them and ask what degree they are....to be sure. Also it is VERY, VERY important to "line" up all the pulleys. Close enough does NOT get it. Easily done redneck style simply with a long straightedge. Sit it flat on the the drive pulley to the next pulley, then the next and see how true all the pulleys line up. You may still have to move the pulleys because there likely not the same width but it gives you a good idea of how straight the pulleys are running in relationship with one another. That is the  most critical part of the whole deal....along with the tention....a really weak spring isn't going to get it.


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