Having way too much flat belt machinery to keep running, The first
thing I will say is that the call for the proper power transmission
belt is dead on. Conveyer won't work. Leather is best, with the
rubberized woven a close second. I don't recommend belt stickem. The
rub-sticks work well, and, for leather, neats foot oil. Not soaked,
just pliable. If you use too much dressing, the belts end up damaged,
slip worse, track poorly, or all of the above.

Idlers generally don't do any good in the long run.

First thing to find is the adjuster for center-to-center distance. On a
drill press, it should be the lower shaft. Ideally, there will be about
1" or more of travel, for a belt length change of 2" or more. If there
is no way to adjust, it is MUCH more difficult to keep the belt running
right.

Shorten up the distance as much as possible, check the shafts for
parallel and the pulleys are aligned (biggest problem with tracking, a
belt with bend or twist being second) If not parallel with the pulleys
in line, adjust them. You CAN NOT get proper tracking or good belt life
with mis-aligned pulleys. Use a tape to get the total length of belt
needed. Get the right belt. Get extra.

Before installing, claen the pulleys. Now, cean them well. Now, clean
them again. No oil, dressing residue, grease, stickem, or other
contaminants.

When you make up the belt, make it about 6" short, and make up a 6"
splice. Install with the splice. You might as well make up a 4" and a
2" as well... you'll need them as the belt stretches. Draw up the belt
tension. How much? Depends on the setup. Under load, the slack side
really can go slack, so no more tension than needed to keep the slack
side from being too slack at maximum load. Most of mine run and track
well with just enough tension not to slip by hand. The belt really
tightens under load. If the slack side is flopping too much, tighten.
It will flop some.

Now, check it... Roll over by hand. Track ok? Bump the motor. Track ok?
Everything turn ok? Run in for a minute or two. Check the adjustment.
As the belt stretches, take up as needed at the bottom shaft. When you
run out of adjustment, remove the 6" patch, and put in the 4". Etc.
Dress the belt regularly with the proper dressing, but not too much.

I'm down to about 5 large belt driven machines at this point (48"X20
foot lathe, 56"X12 foot lathe, a couple of drill presses, and a small
lathe), but they all run fine. The longest belt is just under 30 feet,
vertical, 15HP drive, coming off the reversing clutch-pulley on an
overhead countershaft to drive a lathe. The smallest is 3/4" wide,
about 20", and is the power feed for a good size drill press. All are
joined with belt staples.

If possible, gaurd the belt. Even a couple bars on each side to catch
it when it breaks will do, but a cage is better. The belt is heavy, and
when it goes, it can do real damage.


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