On 7 Dec 2004 11:29:28 -0800, wrote:

Anyone here familliar with flat belt drives? I have an old-style floor
drill press that uses a flat belt to drive the pulley on the upper
cross shaft from the lower one and I want to put it back into running
condition. The belt has a tendency to slip under load and so I added an
adjustable idler near the lower driving pulley, on the side of the belt
that goes down as it is running, but now the belt wants to slip
sideways off the lower pulley when the idler is on. The belt tracks ok
when the idler is not in contact and I tried shimming first one side of
the idler shaft and then the other, thinking the alignement was off,
but this only seemed to make things worse. The idler shaft is paralell
to, and level with, the driving and driven shafts so far as I can tell.
Does it matter which side of the belt the idler is on? The original
belt was missing so I used one made from what looks like black rubber,
1 3/4" wide and 1/4" thick, and running at about 300 rpm. So maybe
rubber is not suitable for this application? Any advice appreciated.
Mike

Yes there are , can't wait to hear the responses. I've debated with
myself over trying to do what you've tried . I put some kind of
fabric and rubberized belt on mine and it could be just a little
shorter. But, will it stretch back to the tightness as I have now
after a couple of hours? I'm sure it will stop at some point after I
run out of alligator parts. It works good enough when I put the tar
type stick on the belt. I would guess that the crowned idler should be
on the inside.