I want to locate a pulley on a shaft. The timing of the pulley is
critical. Once the pulley is located on the shaft the timing location
will be set. Then the pulley will need to come off and be replaced in
the exact position many times. I was thinking that maybe a tapered key
would would work. I would make a key with a large enough taper that it
wouldn't be self locking. I would be depending on the narrow faces of
the key to do the locating. Opinions? I welcome even critical ones.
Thanks,
Eric

fired this volley in
:

I want to locate a pulley on a shaft. The timing of the pulley is
critical.

Snug-fitting keys are probably the most common way. Another common way is
with a roll pin and a diametral hole through hub and shaft.

If you have an odd number of teeth on the pulley, and if you pinned it, I'd
use a tapered pin and taper the hole so it only goes on one way. If the
tooth count is even, it doesn't matter.


Lloyd

wrote:
I want to locate a pulley on a shaft. The timing of the pulley is
critical. Once the pulley is located on the shaft the timing location
will be set. Then the pulley will need to come off and be replaced in
the exact position many times. I was thinking that maybe a tapered key
would would work. I would make a key with a large enough taper that it
wouldn't be self locking. I would be depending on the narrow faces of
the key to do the locating. Opinions? I welcome even critical ones.
Thanks,
Eric

How accurate does the location have to be? I'm wondering if a standard
taper bush and keyway would provide the location you require.

On Fri, 13 Jul 2012 11:13:08 -0700, wrote:

I want to locate a pulley on a shaft. The timing of the pulley is
critical. Once the pulley is located on the shaft the timing location
will be set. Then the pulley will need to come off and be replaced in
the exact position many times. I was thinking that maybe a tapered key
would would work. I would make a key with a large enough taper that it
wouldn't be self locking. I would be depending on the narrow faces of
the key to do the locating. Opinions? I welcome even critical ones.
Thanks,
Eric

Is the location fussy enough that you feel you need the taper to
remove all play? It oughta work, though kind of a pain to make.

If you can tolerate a minimal amount of play, what about a radial pin
thru the shaft and a mating slot in the pulley's hub?
http://www.buytraxxas.com/images/products/3195.jpg

If the torque requirement is modest, I suppose you could make the pin
slightly larger than the slot and push the pulley against the pin with
a threaded knob. That'd eliminate any play, but heavy torque would
tend to cam the pin out of the slot.

Or the slot could be tapered slightly to accept the full dia of the
pin, but provide some interference when it bottoms.

--
Ned Simmons

"David Billington" wrote in message ...
wrote:
I want to locate a pulley on a shaft. The timing of the pulley is
critical. Once the pulley is located on the shaft the timing location
will be set. Then the pulley will need to come off and be replaced in
the exact position many times. I was thinking that maybe a tapered key
would would work. I would make a key with a large enough taper that it
wouldn't be self locking. I would be depending on the narrow faces of
the key to do the locating. Opinions? I welcome even critical ones.
Thanks,
Eric

How accurate does the location have to be? I'm wondering if a standard
taper bush and keyway would provide the location you require.

Maybe use a standard taper-lock but instead of using the tapped holes as-provided, drill and tap your own

wrote in message
...
I want to locate a pulley on a shaft. The timing of the pulley is
critical. Once the pulley is located on the shaft the timing
location
will be set. Then the pulley will need to come off and be replaced
in
the exact position many times. I was thinking that maybe a tapered
key
would would work. I would make a key with a large enough taper that
it
wouldn't be self locking. I would be depending on the narrow faces
of
the key to do the locating. Opinions? I welcome even critical ones.
Thanks,
Eric

Woodruff key.

Broach the pulley's key slot on the centerline of a pulley step so it
can go on either way. You could locate the pulley initially with a
pointed setscrew to mark the position on the shaft. For fine
adjustments later you could machine a custom offset or wider key from
drill rod. I've made several stepped straight keys for non-matching
pulley and shaft slot widths and had no problems with them.

jsw

On Fri, 13 Jul 2012 11:13:08 -0700, wrote:

I want to locate a pulley on a shaft. The timing of the pulley is
critical. Once the pulley is located on the shaft the timing location
will be set. Then the pulley will need to come off and be replaced in
the exact position many times. I was thinking that maybe a tapered key
would would work. I would make a key with a large enough taper that it
wouldn't be self locking. I would be depending on the narrow faces of
the key to do the locating. Opinions? I welcome even critical ones.
Thanks,
Eric


Hey Eric,

How often is "many times"? Would a sliding fit on the shaft to mate
with a fixed dog-clutch or something similar work?

Brian Lawson.

On Fri, 13 Jul 2012 11:13:08 -0700, wrote:

I want to locate a pulley on a shaft. The timing of the pulley is
critical. Once the pulley is located on the shaft the timing location
will be set. Then the pulley will need to come off and be replaced in
the exact position many times. I was thinking that maybe a tapered key
would would work. I would make a key with a large enough taper that it
wouldn't be self locking. I would be depending on the narrow faces of
the key to do the locating. Opinions? I welcome even critical ones.
Thanks,
Eric
--------------
Much depends on the volume. Is this a one off?

You may wish to consider a Cotter. Not the pin but the
split clamp. Very secure, does not weaken the shaft or
cause stress riser problems, and the pulley can easily be
axially and radially adjusted. You may be able to modify a
standard pulley.

A witness mark can be used for exact position replacement or
if the axial location is the important dimension you can use
a split collar to locate.
Example Split collar from Enco
http://www.use-enco.com/CGI/INPDFF?P...PARTPG=INLMK32

some sites to see some cotter clamps
https://www.google.com/search?q=spli...w=1288&bih=537
http://www.google.com/imgres?start=3...:27,s:317,i:93
http://bbs.homeshopmachinist.net/showthread.php?t=23454
http://mysite.verizon.net/t.ferrante.../MillTools.htm
http://www.google.com/imgres?start=1...:21,s:109,i:76
http://bbs.homeshopmachinist.net/arc...p/t-33623.html


--
Unka' George

"Gold is the money of kings,
silver is the money of gentlemen,
barter is the money of peasants,
but debt is the money of slaves"

-Norm Franz, "Money and Wealth in the New Millenium"

On Fri, 13 Jul 2012 23:28:23 -0500, F. George McDuffee
wrote:

On Fri, 13 Jul 2012 11:13:08 -0700, wrote:

I want to locate a pulley on a shaft. The timing of the pulley is
critical. Once the pulley is located on the shaft the timing location
will be set. Then the pulley will need to come off and be replaced in
the exact position many times. I was thinking that maybe a tapered key
would would work. I would make a key with a large enough taper that it
wouldn't be self locking. I would be depending on the narrow faces of
the key to do the locating. Opinions? I welcome even critical ones.
Thanks,
Eric
--------------
Much depends on the volume. Is this a one off?

You may wish to consider a Cotter. Not the pin but the
split clamp. Very secure, does not weaken the shaft or
cause stress riser problems, and the pulley can easily be
axially and radially adjusted. You may be able to modify a
standard pulley.

A witness mark can be used for exact position replacement or
if the axial location is the important dimension you can use
a split collar to locate.
Example Split collar from Enco
http://www.use-enco.com/CGI/INPDFF?P...PARTPG=INLMK32

some sites to see some cotter clamps
https://www.google.com/search?q=spli...w=1288&bih=537
http://www.google.com/imgres?start=3...:27,s:317,i:93
http://bbs.homeshopmachinist.net/showthread.php?t=23454
http://mysite.verizon.net/t.ferrante.../MillTools.htm
http://www.google.com/imgres?start=1...:21,s:109,i:76
http://bbs.homeshopmachinist.net/arc...p/t-33623.html
Thanks everybody for your responses. From all the ideas it sems to me
that I need a better way of location. Since the thing needs to come on
and off many times and the axial location will vary I think that maybe
locating on some flats and using a cam to pull the pulley against the
flats will work. I need to think about this some more. The pulley
needs to come off and be put on quickly.
Eric

On Mon, 16 Jul 2012 07:05:37 -0700, wrote:

On Fri, 13 Jul 2012 23:28:23 -0500, F. George McDuffee
wrote:

On Fri, 13 Jul 2012 11:13:08 -0700, wrote:

I want to locate a pulley on a shaft. The timing of the pulley is
critical. Once the pulley is located on the shaft the timing location
will be set. Then the pulley will need to come off and be replaced in
the exact position many times. I was thinking that maybe a tapered key
would would work. I would make a key with a large enough taper that it
wouldn't be self locking. I would be depending on the narrow faces of
the key to do the locating. Opinions? I welcome even critical ones.
Thanks,
Eric
--------------
Much depends on the volume. Is this a one off?

You may wish to consider a Cotter. Not the pin but the
split clamp. Very secure, does not weaken the shaft or
cause stress riser problems, and the pulley can easily be
axially and radially adjusted. You may be able to modify a
standard pulley.

A witness mark can be used for exact position replacement or
if the axial location is the important dimension you can use
a split collar to locate.
Example Split collar from Enco
http://www.use-enco.com/CGI/INPDFF?P...PARTPG=INLMK32

some sites to see some cotter clamps
https://www.google.com/search?q=spli...w=1288&bih=537
http://www.google.com/imgres?start=3...:27,s:317,i:93
http://bbs.homeshopmachinist.net/showthread.php?t=23454
http://mysite.verizon.net/t.ferrante.../MillTools.htm
http://www.google.com/imgres?start=1...:21,s:109,i:76
http://bbs.homeshopmachinist.net/arc...p/t-33623.html
Thanks everybody for your responses. From all the ideas it sems to me
that I need a better way of location. Since the thing needs to come on
and off many times and the axial location will vary I think that maybe
locating on some flats and using a cam to pull the pulley against the
flats will work. I need to think about this some more. The pulley
needs to come off and be put on quickly.
Eric
===============
If you have a flat on the shaft you may wish to consider a
bicycle crank type tapered cotter. Again you can most
likely modify a standard pulley. Bicycle crank cotters can
be seen at
https://www.google.com/search?q=%22b...1288&bi h=537

Most likely you would want to use a SHCS screw rather than a
nut and washer to wedge the cotter in place. Should give
accurate radial positioning if the cotter to pulley fit is
close and the angle of the flat closely matches the angle of
the hole in the pulley for the cotter wedge. Keep the angle
shallow to maximize the wedging action of the cotter. One
trick is to closely fit a plug in the pulley bore made of
the same material to keep the drill, boring head, reamer,
etc. from wandering when you modify the pulley.

Let the group know what works, and good luck!


--
Unka' George

"Gold is the money of kings,
silver is the money of gentlemen,
barter is the money of peasants,
but debt is the money of slaves"

-Norm Franz, "Money and Wealth in the New Millenium"

On 7/13/2012 2:54 PM, Ned Simmons wrote:
On Fri, 13 Jul 2012 11:13:08 -0700, wrote:

I want to locate a pulley on a shaft. The timing of the pulley is
critical. Once the pulley is located on the shaft the timing location
will be set. Then the pulley will need to come off and be replaced in
the exact position many times. I was thinking that maybe a tapered key
would would work. I would make a key with a large enough taper that it
wouldn't be self locking. I would be depending on the narrow faces of
the key to do the locating. Opinions? I welcome even critical ones.
Thanks,
Eric

Is the location fussy enough that you feel you need the taper to
remove all play? It oughta work, though kind of a pain to make.

If you can tolerate a minimal amount of play, what about a radial pin
thru the shaft and a mating slot in the pulley's hub?
http://www.buytraxxas.com/images/products/3195.jpg

If the torque requirement is modest, I suppose you could make the pin
slightly larger than the slot and push the pulley against the pin with
a threaded knob. That'd eliminate any play, but heavy torque would
tend to cam the pin out of the slot.

Or the slot could be tapered slightly to accept the full dia of the
pin, but provide some interference when it bottoms.


I thought I was the only one to use that method.

wrote in message
...
..
Thanks everybody for your responses. From all the ideas it sems to
me
that I need a better way of location. Since the thing needs to come
on
and off many times and the axial location will vary I think that
maybe
locating on some flats and using a cam to pull the pulley against
the
flats will work. I need to think about this some more. The pulley
needs to come off and be put on quickly.
Eric

Your description is too vague for us to suggest several good
possibilities. How much torque does the pulley withstand, how
accurately must it be positioned, will it be readjusted later, can
tools be used to remove it?

I'd consider mounting the pulley on a keyed bushing with a nut or snap
ring to retain it, and then timing the bushing's position.

Here is a quick one-hand locking device:
http://www.roarksupply.com/Starrett-...arbor56615.htm

A safety-wired nut is pretty quick and simple, and less work to make.

jsw