Inspired by the recent dumb DP question, here's mine:

Is it safe to put the belt at different heights on the pulley cones? It
works with a semi-rigid bicycle chain, after all. I wouldn't want to
mismatch by more than one pulley, because the belt is relatively short.
One could get finer control of the drill speed that way.

Just curious.

--
"Keep your ass behind you."

"Australopithecus scobis" wrote in message
...
Inspired by the recent dumb DP question, here's mine:

Is it safe to put the belt at different heights on the pulley cones? It
works with a semi-rigid bicycle chain, after all. I wouldn't want to
mismatch by more than one pulley, because the belt is relatively short.
One could get finer control of the drill speed that way.

Just curious.

--
"Keep your ass behind you."


Consider that a bicycle chain has an idler to take up the slack. The belt
on different pulleys that are no coplanar would wear out very quickly if you
were able to figure out a way to take out the slack.

In article ,
"Leon" wrote:

"Australopithecus scobis" wrote in message
...
Inspired by the recent dumb DP question, here's mine:

Is it safe to put the belt at different heights on the pulley cones? It
works with a semi-rigid bicycle chain, after all. I wouldn't want to
mismatch by more than one pulley, because the belt is relatively short.
One could get finer control of the drill speed that way.

Just curious.

--
"Keep your ass behind you."


Consider that a bicycle chain has an idler to take up the slack. The belt
on different pulleys that are no coplanar would wear out very quickly if you
were able to figure out a way to take out the slack.

On my cheap Chinese DP, the motor swings on a hinge. Slacken to switch
pulleys, tighten back to run. The edges of the belt would certainly wear
as they rubbed the edges of the pulleys instead of riding the vees.

Photos I've seen in catalogs show that better DPs have three pulley
cones instead of two. I dimly recall that arrangement in high school
woodshop class. If very precise speed settings matter for some
application, the nature of which I am totally ignorant, the wider
variety of speeds offered by triple stacks would be useful. Perhaps in a
one-off situation, one could finesse a two-stack DP into providing an
intermediate speed close to some desired speed. I dunno.

--
"Keep your ass behind you."

On Tue, 20 Jun 2006 16:01:35 GMT, Australopithecus scobis
wrote:

Is it safe to put the belt at different heights on the pulley cones?

No. If the belt isn't flat in the groove (i.e. the pulleys are also
aligned correctly) then you lose an awful lot of friction and you're
likely to have the belt start slipping.

If you must insist on doing this, then use a link belt, not a solid
belt.

Why do you need ultra-fine drill speed control anyway?

On Tue, 20 Jun 2006 18:41:49 GMT, Australopithecus scobis
wrote:


Photos I've seen in catalogs show that better DPs have three pulley
cones instead of two. I dimly recall that arrangement in high school
woodshop class. If very precise speed settings matter for some
application, the nature of which I am totally ignorant, the wider
variety of speeds offered by triple stacks would be useful. Perhaps in a
one-off situation, one could finesse a two-stack DP into providing an
intermediate speed close to some desired speed. I dunno.

In a home shop especially for woodworking the exact speed doesn't
matter. Usually you have a maximum speed, not a minimum so you leave
the drill press set at a slow speed most of the time. The limitation
usually encountered is that the drill press does not have a slow
enough speed, say for a circle cutter, which you aren't going to get
any slower without modification.


-Leuf

Australopithecus scobis wrote:

Inspired by the recent dumb DP question, here's mine:

Is it safe to put the belt at different heights on the pulley cones? It
works with a semi-rigid bicycle chain, after all. I wouldn't want to
mismatch by more than one pulley, because the belt is relatively short.
One could get finer control of the drill speed that way.

If you need that kind of control you might want to look into variable pitch
sheaves. Go to www.grainger.com and search on "variable speed pulley".



--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

In article ,
Andy Dingley wrote:

If you must insist on doing this, then use a link belt, not a solid
belt.

Why do you need ultra-fine drill speed control anyway?

I don't need it. I'm just naturally curious. "Bang the rocks together,
guys."

--
"Keep your ass behind you."

As others have asked - "Why?" As for the bicycle chain analogy, not many
cyclists spin their cranks at 1700+ rpm. And cyclists prefer to keep their
chains relatively straight, avoiding the gear combinations with the most severe
angles.
--
JeffB
remove no.spam. to email

In article ,
Australopithecus scobis wrote:
Inspired by the recent dumb DP question, here's mine:

Is it safe to put the belt at different heights on the pulley cones? It
works with a semi-rigid bicycle chain, after all. I wouldn't want to
mismatch by more than one pulley, because the belt is relatively short.
One could get finer control of the drill speed that way.

Just curious.

--
"Keep your ass behind you."

Not good for the belt, of course, and there's always the possibility
that a belt could be thrown, though I have seen some misaligned belt
drive pulleys run for quite a while without trouble. I don't think it
would work too well on the typical drill press setup, though; how
would you tension the belt?


--

Larry Wasserman Baltimore, Maryland