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I have not been able to get the feed belt from drifting. Here is the history. When new, the belt drifted to the outside edge, ground into the belt guides, and frayed the belt. Adjusting the tensioners had no effect. I could tighten the outside tensioner very much and loosen the inside so that the belt was completely slack on the inside, yet the belt would still pile up on the outside edge. JET assumed the belt was manufactured incorrectly with non-parellel edges and JET sent me a new belt. I let this sit for about two years because I was not building. I just replaced the belt and I have the same problem. I'll call JET Monday, but meanwhile I am wondering if anyone else has seen this same problem and how was it corrected.

You may want to check this video out on fine tuning your drum sander. I'm not sure if your drum sander has the same type of adjustments as this one, but it may be helpful. The tracking adjustment part starts around 11:00. Hope this helps a bit.

http://m.youtube.com/watch?v=iNnTwdzCemw

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Brad

Brad, thanks, but it does not help. The adjustment procedure is basically the same as mine, but it just doesn't work. It has me stumped, because the design of the adjusting mechanism seems foolproof.

I found this for the Jet, while looking to solve the same problem for my Delta.
https://www.ridgidforum.com/forum/t29058/.
Hope it helps.

Bob

The rubber drive roller on the Jet is supposed to be crowned. They wear out, especially if you have the tension cranked too high. Take off the belt and check out the condition of the drive roller. If it's worn, it will never track straight.

I also suggest that you never use the aftermarket belts for it (really just a standard size sanding belt). I've tried several and none of them are made precisely enough to track well on the Jet in my experience. Consider upgrading to the poly belts. I wish someone made a poly belt for the 22" one I have. I would snatch it up.

Everything is basically new. I barely used the machine, because it came with this defect when new, and I was not building for a few years. The replacement belt is new and it was from JET. If the crown is out of the drive roller, it must have come that way. Unless I am missing something, the web site seems to just go through the standard adjustments, which I have tried repeatedly.

Thanks for the suggestions. If JET is able to solve this, I'll post the result. Meanwhile, if anymore suggestions, I would appreciate it.

I don't have any solutions for you, but we can commiserate together. I've been fighting the same problem
for about a year. Nothing has seemed to help. I tried two different belts, putting a couple of wraps of tape
on the drive roller to increase the crown, have fiddled with all the alignments, nada

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Gene

Politicians and diapers must be changed often, and for the same reason- Mark Twain

I had the same problem when I changed belts on my older Performax 16-32. The solution was to get it adjusted as close as I could, then place 2 ceramic belt guides on the bottom, they are magnetic and stuck onto the underside. Completely solved it. They have a V-shaped smooth groove that the edge of the belt rides in and keeps gentle pressure on it without fraying it. It was a Performax part at the time that I picked up at a woodworking store. It would be worth calling Jet (who bought Performax) and see if they still make it.

It came with the belt guides. They don't help in this case.

I also have the belt guides and they haven't helped much. The only way I've been able to use the
sander is to keep the belt very loose- so loose that I have to watch and often help each piece of
wood go through the sander, because the belt often slips. But any tighter with the belt adjustments
and the edge guides start eating the edge of the belt. I did order a new drive roller, based on John
Coloccia's comment above. It was right around $25, and I'm desperate enough to spend more than
that if it would fix my problem. I'll report back if it helps.

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Gene

Politicians and diapers must be changed often, and for the same reason- Mark Twain

I'm curious if the new roller ended up working for you, Gene? Debugging stuff like this can be maddening.

Meanwhile, I noticed that the drive roller on my machine is not parallel to the front edge of the bed. The outboard side is about 0.031 - 0.035" closer than the inboard side. I asked JET to evaluate this, but they are slow. I have ordered a new outboard bracket in the hopes that this is the defect. But, the defect might be that the holes were drilled wrong on the inboard side, in the housing for the drive. Or, the threaded holes in the table could be in the wrong spots. There are no adjustments for this problem that I can see. So, if the new outboard bracket is the same distance as the old one, I will then just manufacture a new bracket. It will not work to enlarge the bracket holes to slide the bracket for adjustment, because the bracket will be under tension and vibration, therefore certain to slip back.

It makes sense that this could be the problem. Adjustments of the back roller cannot change the fact that the belt is always aimed on a different path than the orientation of the bed.

I would be interested in feedback from everyone regarding if their feed roller is not parellel to the bed. If so, are they able to keep the belt tracking?

Update.

I seem to have it working, but not for the reason I guessed. My machine had the drive roller not parallel to the bed. I made a new outboard bracket to line up the roller, but that had no effect. JET recommend a new drive roller and a new belt. Both have had their design changed since I purchased the machine. The new roller is knurled metal, instead of rubber; and the new belt is a very flimsy 3M product instead of the heavy Bear belt that I had before. So, now it works, but I do not know which of the two items was responsible. The old roller was still like new--very pliable and it rolled on a flat surface without any indication of irregularity. I suspect it's possible that the diagonal seam on the old belt was interacting with the roller and driving the belt to one side, but I do not know. I do not want to do any trials switching out belts and rollers in different combinations to satisfy my curiosity. If it was the belt, that is consistent with those of you who reported that switching to the poly belt solved your problems.