Hi all,

Having been busy with other things, I haven't started to build my stone
polisher yet, but I've had chance to ponder the design a little. Often I
like to do this because I find after a week or two a smart idea will
come into my head, which I would otherwise have missed.

Anyway, I have a small problem with bearings. I intended to use
self-aligning ball races in pillow blocks, but it turns out that the
pillow block for a 1/2" diameter shaft is 5" long! So I can't get the
shafts closer than 5" apart unless I stagger the pillow blocks, which
will look messy. I want about 4" between the shafts, and I might make
this distance adjustable to allow different barrel sizes to be used on
the same machine.

Pillow blocks don't seem to be available for shafts less than 1/2"
diameter. I don't have access to a milling machine, so I can't make my
own "double pillow block" to carry two ball races. One idea I've had is
to use rod end bearings (as used in pneumatic cylinder linkages etc).
These could be attached to a base plate with a single bolt, provide the
self-aligning feature, and to cater for the rotation I could press a
bronze bush into the eye. I've checked and I can get components of the
right dimensions to make this work, but my local bearing supplier didn't
want to recommend it because the idea was unconventional.

What do people think? Will rod end bearings with a bronze insert stand
up to continuous use in a rock tumbler if I keep them clean and well
lubricated? Any thoughts would be much appreciated.

Best wishes,

Chris

Chris,
Consider using two parallel shafts (length to suit length of drum (s)
you are planning to use, but mount two rubber "tires" on each shaft,
one on each side of the barrel at the bottom and one on each side of
the barrel at the top. If they are spaced right, and if the tires are
of sufficient diameter, many different size drums can be placed on the
tires and still be rotated. The rubber tires will dampen the noise a
bit, provide good "traction" for the drum, will last forever, and will
eliminate the need for moving the shafts apart or closer for different
size drums. Just a thought.... HTH
Ken.