Tracking wheel size??

K

Ken H>

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Dec 31, 2011
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Hello all - I've seen grinders with the tracking wheel ranging from 2" to 5", maybe 6". Is there a real advantage to a larger size tracking wheel? What would be considered the optimum size?

Looking at this for the horizontal grinder. The more I think about this, I suspect I'm going to actually build one before long.
 
I've wondered about this myself. Something tells me there's probably not a massive difference, but belt angle has to be factor too, I would imagine.
 
I think a larger tracking wheel is better and I have put larger tracking wheels on both my grinders...one is a KMG and the other is a modified Polar Bear Forge grinder. Both grinders track better with a larger tracking wheel. I like tracking wheels with a slight crown in the middle. I like the ones sold on Ebay by a vendor called Jackstraw. They are well made and I also bought a larger drive wheel and had it turned down to the diameter I wanted by a machinist. My tracking wheels are 4 inch but I wouldn't hesitate to go five or even six inches if I could find them at a reasonable price. It is my opinion only but it doesn't cost much to switch one out. Larry
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Bearings will last longer in a larger tracking wheel. I also believe it improves tracking. I run 6" tracking wheels. If you're worried about belt angle the only thing you need to do is make a longer tracking hinge plate and mount the wheel a half inch lower for every inch of diameter increase. My next grinder will have multiple tracking wheel mount holes to test the belt angle and offer leeway on usable belt length.
 
Thanks to all for the input. Ya'll confirm what I was thinking since TW-90 and a few other grinders are using larger tracking wheels. I've been using 3" diameter tracking wheels on my grinders which work just fine. Since I didn't have anything to compare with I asked the question. Perhaps I'll make a 4" wheel and try that. I'd love to have a bit of 5" or 6" rod to make the wheel from.

I put the crown in the tracking wheel, but run the drive wheel flat. I've read only one wheel should have the crown, otherwise they tend to fight between the two crowns to provide the "track".

Ken H>
 
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Larry, that photo of your tension arm is interesting. It looks like it pivots in two places. Can you provide a couple of photos from different angles so I can better understand how it works?

Ken H>
 
Bigger has been better for me. I think what really matters is surface contact. If your belt path is routed in a way that has minimal "wrap" around the tracking wheel, the bigger diameter tracking wheels allow for more contact area.

And I think the second "pivot" you're seeing on Larry's grinder is just a handle extension.
 
Ken H, if I had it to do over again, I wouldn't crown the drive wheel. You don't want to flatten your tracking wheel. The tracking wheel "turns" the belt, and the crown itself acts as the "steering wheel". You want that steering effect to occur just PRIOR to your attachment.
It's very true that two crowns can fight each other. If the crowns are misaligned, whether linearly, or angularly, it's like having two steering wheels in your car and the passenger is drunk. If you have reverse, you can test their alignment by running both directions and seeing if the belt remains centered. This is, in my opinion, the best reason to have a c-face motor and direct drive.
The reason I would have left my drive wheel flat is because I believe two crowns causes contact wheels to get dished much faster. The crown actually causes the belt to be TIGHTER in it's center. Two crowns DOUBLES this tension.
Contact wheel wear is inevitable. For this reason, given a choice, I would also cut a slight dish into my tracking wheel like many grinders and sanders used to have. This would cause contact wheels to wear in a convex fashion. I would much rather work on a contact wheel with this type of wear than dished.
Sorry so long winded. Just a little food for thought.
 
Ken H> said:
Larry, that photo of your tension arm is interesting. It looks like it pivots in two places. Can you provide a couple of photos from different angles so I can better understand how it works?

Ken H>
Click to expand...
That is a handle extension bolted to what used to be the handle hole. I made an aluminum extension and mounted the handle at the top. This was a stock KMG that I added a second tool arm slot to and changed the spring to a gas piston. I changed all the tool bars to aluminum which saves a ton of weight...about 10 pounds per arm and wheel. Larry

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