On 29/11/2019 13:07, Chris Green wrote:
I have a small fan motor that I need to replace, the fan is mounted on
an aluminium (I think) collar which is siezed on the shaft.

So, what's a good approach to getting it unstuck? I've drilled out
most of the grub screw that should be holding it, I doubt that's the
issue now. It's just that the collar is very firmly stuck on the
shaft.

There's lots of "how to get steel studs out of aluminium cylinder
blocks" advice I can find on the web but my problem is the other way
around. Is there anything in particular that might help apart from
all the usual things like soaking in penetrating oil, bashing it,
etc.?

It's quite small, the shaft is about 7mm (possibly 1/4") diameter. The
end protrudes only 1cm or so beyond the fan, I can hold it in a vice
quite firmly but the fan is quite flimsy so brute force rotation of
that is rather difficult.

Steel on aluminium can be a bugger. If the motor is dead, I'd be
inclined to destroy the motor in an attempt to save the fan. Angle
grinder, dremel, etc. depending on the size. Once you have the fan with
just an inch of motor spindle it becomes comparatively easy, I'd start
by removing the grub screw, soaking the lot in penetrating fluid of your
preference, and then finding suitable spacers to let you push the
spindle out in a press, or a pillar drill, or a vice. Once it has moved
a bit it should be easier to remove e.g. with a mole wrench.