Replies

1. 
   jeffn7 | Apr 23, 2002 07:12am | #1

   my unisaw had the same issue. I fiddled with the belt adjustment a lot in the beginning and got it to a point where it wasn't intolerable. After a couple of months of steady use, it just kind of worked itself out. My symptom was a little jolt when I started, I didn't have any vibration when running the saw, and one of the belts was in fact a little (maybe 1/8") shorter than the others.

2. 
   bckelly01 | Apr 24, 2002 02:53am | #2

   Mike,

   I have a new unisaw that's about 2 months old and had a similar but less severe problem. When I set it up, the middle belt was much looser than the two outside ones and I couldn't improve the situation much. So, I turned it on and started working. After working with it a bit, the middle belt is still a bit looser, but not as much as it was out of the box. Saw runs o.k. without belts flopping around. It does bother me, but saw works well anyway. I also had some trouble getting the extension table to line up just flush with the extension wing. If you get any satisfaction out of Delta please let us know.

   BCK

3. 
   alexlisa | Apr 24, 2002 03:32pm | #3

   Have you tried the link belts? I don't have a unisaw, but installing a link belt on my Jet contractor's saw made a huge reduction in vibration. The link belts are not supposed to take a "set" like rubber ones.

1. 
   RickL | Apr 24, 2002 06:10pm | #4

   Link belts work best on an application where the motor is suspended by it's own weight.  The memory in a standard belts makes it bounce and on the up bounce you loose power. Also the belts are a lot longer on a contractor saw. On a unisaw the belts are shorter and held in a fixed tension. New belts will equalize and stretch to the same length in use.  They  sell matched set which are very expensive. I haven't found it necessary to bother with matched sets for most purposes.  Just buy 3 belts at the same time.   Cogged belts are nice for smaller pulleys and not much more in price.

4. 
   Trees2dust | Apr 26, 2002 11:39pm | #5

   Mike,

   I just replaced the stretched-out belts on a unisaw.  They weren't causing vibration, probably because they appeared to be equal in length, but they were flopping around even though the motor was in its lowest position.  The belts measured 25" on the outside, and I figured they needed to be 24", so I bought three 4L240 (24") belts at the local Grainger industrial supply house.  The belts measured to within 1/8" of each other.  It took some effort to slip the belts on, but now the motor has plenty of adjustment left should the belts stretch.

   So my suggestion is to replace the belts.  It cost about $10 for 3.  No need to buy a matched set, but take a sewing tape measure with you and confirm that the belts are of equal length by measuring around the outside.

   Rick in So Cal

5. 
   lwilliams | Apr 27, 2002 04:33am | #6

   Mike,

   If you replace the belts, make sure and replace them with a matched set. A matched set will be cut sequentially off the master roll and will be the same length. Industrial supply houses such as MSC (http://www.mscdirect.com) stock matched sets.

1. 
   trialnut | Apr 28, 2002 03:45pm | #7

   Length is not the only factor considered in a matched set. The cross section is also the same. As a belt gets wider in cross section it will ride higher up on the pulley which in effect makes it shorter. As there is a plus/ minus tolerance on belts if you do not buy a matched set, even though they all measure the same length they could be different.The Professional Termite, aka Woodbutcher Extrodinaire

6. 
   user-63031 | Apr 29, 2002 05:26am | #8

   Mike, I didn't think the matched set was important. It is. To get a matched set just make sure all the numbers on the belt match, not just the model #. My guess is a matched set from Delta will be considerably more than a local industrial supply. My 1944 Unisaw runs like a dream with new matched belts.

1. 
   patternmaker | Apr 29, 2002 01:30pm | #9

   Mike: I replaced belts and bearings about a year ago. The bearings from a local source,the matched belts from Delta.While the arbor was out,I took a skin cut off the face of the flange.Maybe not necessary,but it assured a runout free arbor.The belts when new,when laid flat on the bench,were oval shaped.I stacked one on top of the other for the closest match and put a chalk mark across all three belts.When installed,the chalk marks line up.Nit picking?Maybe so,but the saw never ran smoother which transfers to the quality of the cut. FWIW ¬¬¬¬¬¬¬¬¬¬PAT¬¬¬¬¬¬¬¬¬¬ Thank you,Mr. Croney,wherever you may be

1. 
   arcticcat | May 05, 2002 06:58am | #10

   Thanks for the input everybody. I'm going to try Pats suggestion of marking the belts with chalk. If that doesn't work, I think I'll get a set of matched belts.

   Mike.