Making Some Pulleys, Have Question About Tracking ?

Dennis Towns

Dennis Towns

Joined
Jun 8, 2006
Messages
253
I pulled an old 1x42 sander out of retirement and looked it over and found the tracking pulley had a crack. Soooo, cause I had the right size aluminum stock and machines I thought I would make all 3 pulleys from aluminum and eliminate that ever happening again. Not sure what I need it for yet. My Question : On the tracking pulley don't they have a slight crown in the center ? I cut about a 3 degree crown in one and stamped it with a C so not to mix it up. Does anybody have knowledge of how much crown in a 1" wide 3 1/2" pulley would be ? Heres a couple pics.42 grinder.jpeg 42 grinder 4.jpeg 42 grinder 5.jpeg
 
Yes crown or radius the tracking wheel as well as the drive wheel. I don't know of the exzactly amount but it sure helps with keeping the belt tracking straight.
 
I did not know the drive pulley also had some. I can do that. Using like a 3 degree gives it a slight crown right in the center. I will try the 3 degree and find out. After boring them for bearings I am going to remove some of the material to lighten them up. Hey its a challenge and makes me want to go to the shop. LOL.
 
For what its worth I don't like a crowned drive wheel. My grinder had both crowned, and always had persistent tracking issues until I eventually turned the crown off the drive wheel. It's flawless now
 
Weird, I have allways had a crowned drive wheel and never had a problem
 
I think the grinder has a lot to do with it. If everything is lined up perfectly a crowned drive wheel will work. If anything is out at all, it seems to fight against the tracking wheel.
Belt wouldn't move while adjusting tracking, then suddenly jump over a bit, and keep having to chase it back and forth. Once I turned the crown off the drive wheel it tracked smoothly and held its spot rock solid.

It seems rather hit and miss depending on the specific machine
 
Well I made mine and every part is machined so it's as square as I could make it. I do notice that to much crown can bow your belts.
 
Well the good thing is I have about 24" of this big round stock so I can make me some more if needed. I will tell you this, it took me longer to make this first one than I thought it would. But I have to take it slow and think it thru not being any type of machinist . It turned out pretty good. I ordered new bearing to put in before I put it back together. Not sure about the 3 degrees but I can see and feel the crown so it might be too much. Here is a pic of the first one. Thanks for the input.42 grinder 7.jpeg 42 grinder 8.jpeg
 
3 degrees is more than I put on them. I only do 1.5.
 
I've read that a crown on both drive and tracking wheels causes them to fight each other giving the effects mentioned above by Geoff. That might be less of a problem with 1.5⁰ crowns. I tend to use 3⁰ crown on drive wheel only.
 
That makes sense to me about fighting each other. I had a couple crowned wheels on my flat platen initially, and I hated life until I replaced them with flat wheels.
 
Those photos of the wheel sure make it look like you did a good job making the wheels. With only crown only on drive wheel, I like a pretty obvious crown. To test what a crown will do, you can also wrap electrical tape around the center of the wheel - make it several layers to build up 1/8" depth. If using 1/2" tape, make the tape about 1" wide at base, building up to 1/2" wide in center. Surprising how long that tape will last for testing a large crown.

Yes, I like flat wheels on my platen - much better for grinding on wheel when desired. That's why I changed from aluminum wheels to 3" diameter skateboard wheels. Got the nice poly covering for better grinding.

Later
 
I am using wheels from Beaumont metal works (KMG) and would have bet you the drive wheel was flat but I just checked and both the drive and tracking wheels are crowned.
 
Thats good to hear. But even if if needs it I can turn the crown down. Here is the finished set. And a pic of my shop mascot .
 

Attachments

  • 42 grinder 9.jpeg
    42 grinder 9.jpeg
    68.5 KB · Views: 10
  • 42 grinder 10.jpeg
    42 grinder 10.jpeg
    72.7 KB · Views: 9
I've seen everything from no crown on any wheels, to just on the tracking, to both drive and tracking, and any of them will work just fine, assuming that your wheels are in line and square with each other. My two machines have both tracking and drive wheels crowned, and I've never had a problem with them.

I did make a flat drive wheel once to try with a machine that I was trying to run in reverse, as I though the crowned drive may have been fighting the tracking wheel, but I don't think it made a bit of difference for what I was trying to do.

I think proper tension and alignment is more important than any degree of crown, though crown can definitely help compensate for variances in either.
 
Welllllllll, it runs. I am not tickled with the tracking. It would not pull the belt inwards enough, lacking maybe a 1/16th. So first I took the tracking crown from 3 to 2 degrees and no help. So then I took the crown off the drive pulley, nope. So then I pulled the tracking shaft and knocked the pizz out of it to give it a little tilt up. Still not quite right, so I shimmed the tracking pulley a bit and it has the belt tracking all the way in now but there is nothing left if I need it. So might have to build another tracking pulley down the road. It might need more instead of less crown. But hey it is usable like it is for now.:thumbsup:
 
Is that with a wheel or a platen? Most of the time I've "run out of tracking" it's because whatever tool arm I just made is out of kilter. And shimming it one way or the other does the trick.
 
That is with the factory platen. Its a Delta. I was guessing on how much crown so maybe I am off on that.
 
You must log in or register to reply here.
Back
Top