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Default Flat Belt Drives

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

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Sunworshipper
 
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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.
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Tom Gardner
 
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Did you try dressing? I don't like the idea of an idler but I don't know
why. I don't like the idea of rubber. is it stretchy? Can you get a
leather or plastic belt?

wrote in message
oups.com...
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



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John
 
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wrote in message
oups.com...
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

Wow! Flat belt drives.....boy does that bring back some old memories. I
once worked (early 70's) at a farm machinery manufacturer in So. Idaho and
they had three machines (lathes) that were flat belt drive machines (babbitt
bearings too ). They had a main shaft, overhead drive unit that ran all
three machines. I don't remember exactly how it worked because I tried to
stay away from those machines as much as I could. Hmmmm, I wonder if there
are any shops that still use .......? No! Couldn't be!

John


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Tom Dacon
 
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stay away from those machines as much as I could. Hmmmm, I wonder if
there
are any shops that still use .......? No! Couldn't be!


As late as 1975, there was a machine shop in Venice, California, that ran
almost all the machines in the shop via belt drives off a great big electric
motor that sat outside the building in its own little shed. A shaft came in
the wall and distributed power to at least three shafts, spaced along the
ceiling, that ran all the way from one side of the shop to the other.
Wherever there was a machine, there was a flat pulley on one of the overhead
shafts, and a leather belt and idler pulley with a cam-over lever arm to
engage the machine. I used to drop by there from time to time just to watch
the whole thing run.

A year or two later, the owner had retired and sold the shop, the new owner
had torn the building down, and God only knows what happened to all that
lovely machinery.

Tom Dacon




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The idler is not crowned. It more resembles a long aluminum rolling pin
about 3 5/8" o.d. I considered putting it on the inside of the belt but
it seemed that it would give more contact area on the driven pulley if
it was outside, however, I don't know if it would be better to have it
on the left outside or right outside of the driven pulley.
Mike

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KyMike
 
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The idler is not crowned, it more resembles a long aluminum rolling pin
about 3 5/8" O.D. I considered putting it on the inside of the belt but
it seemed that it would give more contact with the driving pulley on
the outside, however I don't know if it would be better to have it on
the right outside or left outside of the driving pulley.
Mike

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KyMike
 
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The idler is not crowned, it more resembles a long aluminum rolling pin
about 3 5/8" O.D. I considered putting it on the inside of the belt but
it seemed that it would give more contact with the driving pulley on
the outside, however I don't know if it would be better to have it on
the right outside or left outside of the driving pulley.
Mike

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KyMike
 
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The rubber is stretchy and seems slippery on the surface, though I
thought if I could get it tight enough it would do for now until I can
find something better. I have not tried dressing because I'm not sure
what to use on rubber belts or if it would only make things worse.
Mike

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KyMike
 
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The rubber is stretchy and seems slippery on the surface, though I
thought if I could get it tight enough it would do for now until I can
find something better. I have not tried dressing because I'm not sure
what to use on rubber belts or if it would only make things worse.
Mike



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KyMike
 
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The rubber is stretchy and seems slippery on the surface, though I
thought if I could get it tight enough it would do for now until I can
find something better. I have not tried dressing because I'm not sure
what to use on rubber belts or if it would only make things worse, but
its an idea.
Mike

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Vince Iorio
 
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Mike,

You don't need an idler. You need to get the right type of belting. I
recommend what they call flat transmission belting. You can get it from
MCMaster-Carr.

http://www.mcmaster.com/

It's less then a buck a foot. The bigger cost is getting a clipper
lacing tool, or you could use alligator lacing. The trick is trying to
figure out the right length. I normally rap the belt around the pulleys
and pull it tight. I mark the length on the belt, and then subtract out
the length of the clipper lacing, then I subtract out another .5" to 1"
and cut the belt. If it is to lose, then cut off just the clipper
lacing from one end and try again.

If the tension is right, then you don't need any dressing.

Vince




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




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You just need belt dressing... The stick form was the best... No one
sells it anymore...

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Nick Hull
 
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In article . com,
"KyMike" wrote:

The idler is not crowned, it more resembles a long aluminum rolling pin
about 3 5/8" O.D. I considered putting it on the inside of the belt but
it seemed that it would give more contact with the driving pulley on
the outside, however I don't know if it would be better to have it on
the right outside or left outside of the driving pulley.
Mike


My SWAG is that if the idler is close to the pulley it will interfere
with the crown action, try putting the idler far away from either
crowned pulley.

--
Free men own guns, slaves don't
www.geocities.com/CapitolHill/5357/
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KyMike
 
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Thanks for the replies everyone.
Mike



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Wolfcrow Warrior
 
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flat belts don't you just love them. use them on conveyers at work make sure
you are getting at least 50% contact on pulley and you should not have any
slip, if using idler move away from the driving pulley. The more contact you
have on the driven pulley the better should stop the slipping
Troy L Gilbert

"John" wrote in message ...

wrote in message
oups.com...
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

Wow! Flat belt drives.....boy does that bring back some old memories. I
once worked (early 70's) at a farm machinery manufacturer in So. Idaho and
they had three machines (lathes) that were flat belt drive machines
(babbitt bearings too ). They had a main shaft, overhead drive unit that
ran all three machines. I don't remember exactly how it worked because I
tried to stay away from those machines as much as I could. Hmmmm, I
wonder if there are any shops that still use .......? No! Couldn't be!

John




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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


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KyMike
 
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That is exactly the problem I'm having with it, the designers did not
provide a way to adjust the upper and lower shaft spacing, though it
might be possible to do this by mounting the lower pulley shaft on some
sort of pivoting arm. This drill press came out of a 100 year old shop
and you would think that even back then they would have known that
belts stretch over time. I'm pretty sure the shafts are in line because
the belt tracks all right without the idler, but it looks like I don't
have the right type belt. Thanks for the info.
Mike

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Well, there may be a way (one on mine is shimmed under the mounts for
the shaft) but the easiest is to lace the belt rather than use staples.
You can snug up lacing as the belt stretches.


KyMike wrote:
That is exactly the problem I'm having with it, the designers did not
provide a way to adjust the upper and lower shaft spacing, though it
might be possible to do this by mounting the lower pulley shaft on

some
sort of pivoting arm. This drill press came out of a 100 year old

shop
and you would think that even back then they would have known that
belts stretch over time. I'm pretty sure the shafts are in line

because
the belt tracks all right without the idler, but it looks like I

don't
have the right type belt. Thanks for the info.
Mike


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