I have a nicer old motor and one of those tapered-threaded mandrels for
cotton buffs, and I need a buffer. The motor shaft is smaller than the
hole in the mandrel. I can turn a "bush" to fit between them.

The motor shaft has a flat, and the mandrel two setscrews. Do I

a) drill, thread, and setscrew the bush to the shaft, then setscrew the
mandrel to the bush;

b) drill and pin the bush & shaft, then as a); or

c) insert the bush and lock it with one setscrew, mark the centre of the
other setscrew hole, swap setscrews and repeat, take the bush out and drill
clearance holes so the setscrews bear on the shaft; or

d) do something else?

a) might be tricky as the bush wall is likley to be 1/8 or so. b) is the
way I'm leaning - the pin will be retained by the mandrel. c) has the
advantage of complete removability, and I might want the motor for
something else.

On Aug 25, 2:34*am, _
wrote:
I have a nicer old motor and one of those tapered-threaded mandrels for
cotton buffs, and I need a buffer. *The motor shaft is smaller than the
hole in the mandrel. *I can turn a "bush" to fit between them. *

The motor shaft has a flat, and the mandrel two setscrews. *Do I


c) insert the bush and lock it with one setscrew, mark the centre of the
other setscrew hole, swap setscrews and repeat, take the bush out and drill
clearance holes so the setscrews bear on the shaft; or


I would do something like C. Maybe just make the bushing, measure the
distance between the two setscrew holes, and drill two holes in the
bushing the correct distance apart. The holes can have generous
clearances so the bushing can still work even if the holes are not
exactly the right distance apart.

Dan

On Tue, 25 Aug 2009 01:34:35 GMT, _
wrote:

I have a nicer old motor and one of those tapered-threaded mandrels for
cotton buffs, and I need a buffer. The motor shaft is smaller than the
hole in the mandrel. I can turn a "bush" to fit between them.

The motor shaft has a flat, and the mandrel two setscrews. Do I

a) drill, thread, and setscrew the bush to the shaft, then setscrew the
mandrel to the bush;

b) drill and pin the bush & shaft, then as a); or

c) insert the bush and lock it with one setscrew, mark the centre of the
other setscrew hole, swap setscrews and repeat, take the bush out and drill
clearance holes so the setscrews bear on the shaft; or

d) do something else?

a) might be tricky as the bush wall is likley to be 1/8 or so. b) is the
way I'm leaning - the pin will be retained by the mandrel. c) has the
advantage of complete removability, and I might want the motor for
something else.



Hey ,

Well "nicer old motor " or not, with your comments that the "bushing"
will be made to accommodate a shaft about 1/4" diameter smaller, and
that is already weakened slightly by having a flat, one thing to
consider is whether the smaller shaft can take the same forces as the
buffing mandrel was designed for. It is quite amazing to see a shaft
unsecured make a severe bend when it starts to "whip" due to applied
forces beyond its limits.

Take care.

Brian Lawson,
Bothwell, Ontario.

On Tue, 25 Aug 2009 01:34:35 GMT, _
wrote:

I have a nicer old motor and one of those tapered-threaded mandrels for
cotton buffs, and I need a buffer. The motor shaft is smaller than the
hole in the mandrel. I can turn a "bush" to fit between them.

The motor shaft has a flat, and the mandrel two setscrews. Do I

a) drill, thread, and setscrew the bush to the shaft, then setscrew the
mandrel to the bush;

b) drill and pin the bush & shaft, then as a); or

c) insert the bush and lock it with one setscrew, mark the centre of the
other setscrew hole, swap setscrews and repeat, take the bush out and drill
clearance holes so the setscrews bear on the shaft; or

d) do something else?

a) might be tricky as the bush wall is likley to be 1/8 or so. b) is the
way I'm leaning - the pin will be retained by the mandrel. c) has the
advantage of complete removability, and I might want the motor for
something else.

I would do (c). The setscrews will transmit torque from shaft flat
to mandrel. All the bush need do is keep mandrel and shaft
concentric. It could have considerably less than 1/8" wall thickness
with no problem.

On Tue, 25 Aug 2009 01:34:35 GMT, _
wrote:

I have a nicer old motor and one of those tapered-threaded mandrels for
cotton buffs, and I need a buffer. The motor shaft is smaller than the
hole in the mandrel. I can turn a "bush" to fit between them.

The motor shaft has a flat, and the mandrel two setscrews. Do I

a) drill, thread, and setscrew the bush to the shaft, then setscrew the
mandrel to the bush;

b) drill and pin the bush & shaft, then as a); or

c) insert the bush and lock it with one setscrew, mark the centre of the
other setscrew hole, swap setscrews and repeat, take the bush out and drill
clearance holes so the setscrews bear on the shaft; or

d) do something else?

a) might be tricky as the bush wall is likley to be 1/8 or so. b) is the
way I'm leaning - the pin will be retained by the mandrel. c) has the
advantage of complete removability, and I might want the motor for
something else.

==========
Always try the easy/simple solution first.

You are going to use this for buffing, so run-out is not
critical.

Try making a bushing, split one side with a hacksaw, and install
with the split at 90 degrees to the set screws, with the set
screws *NOT* over the flat on the motor shaft. Tighten to a
reasonable torque, install a buffing wheel and have a go.

More than likely this will be more than adequate for the typical
home/hobby shop.


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

On Aug 24, 6:34*pm, _
wrote:
I have a nicer old motor and one of those tapered-threaded mandrels for
cotton buffs, and I need a buffer. *The motor shaft is smaller than the
hole in the mandrel. *

My preference would be to mount pillow blocks and fullsize shaft for
the
mandrel, and offset the motor with a pulley where it won't interfere.
That way, you can have a left and right mandrel (two buffers or
buffer and a fine wire wheel), and can update the motor power or
change the rotation speed (by choosing different pulleys) or
direction.

The buffer wheels are replaceable, so should the motor be.

On 2009-08-25, _ wrote:
I have a nicer old motor and one of those tapered-threaded mandrels for
cotton buffs, and I need a buffer. The motor shaft is smaller than the
hole in the mandrel. I can turn a "bush" to fit between them.

The motor shaft has a flat, and the mandrel two setscrews. Do I

a) drill, thread, and setscrew the bush to the shaft, then setscrew the
mandrel to the bush;

b) drill and pin the bush & shaft, then as a); or

c) insert the bush and lock it with one setscrew, mark the centre of the
other setscrew hole, swap setscrews and repeat, take the bush out and drill
clearance holes so the setscrews bear on the shaft; or

d) do something else?

a) might be tricky as the bush wall is likley to be 1/8 or so. b) is the
way I'm leaning - the pin will be retained by the mandrel. c) has the
advantage of complete removability, and I might want the motor for
something else.

Given the wall thickness of the bush, I would suggest (c) is the
best bet. This is assuming that the two setscrews on the mandrel are in
a straight line, instead of set at different angles around the mandrel.
(You don't want a setscrew tightening onto any area of the motor shaft
other than the flat, or the burrs raised may prevent disassembly.
You probably should get somewhat longer setscrews to keep enough threads
in the threaded section of the mandrel.

Good Luck,
DoN.

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