On Tue, 12 Jan 2016 19:27:41 -0600, amdx wrote:

On 1/12/2016 4:10 PM, Ed Huntress wrote:
On Tue, 12 Jan 2016 15:59:08 -0600, amdx wrote:


I have one of the Harbor Freight 7 x 10 lathes.
I have a bicycle seat post that I want to reduce the diameter by 0.025".
The spindle head is to small to accept the post, the bed is to short to
use the tail stock.
Any clever ideas how I could use this lathe to do the job. The post is
aluminum.
I took it to a machine shop, he laughed and said, "I've already spent
more time on this than the part is worth."

Mikek

You need a steady rest (Google "lathe steady rest"). For a one-shot
that doesn't sound at all critical, cutting aluminum, you can make one
out of plywood that will do the job.

Yes, as I wrote the question, I thought, I could make a holder for the
live center out of wood and bolt or clamp it to the end of the bed.
I did see a steady rest someone built for their mini lathe, it was
very nice but quite a project.

You may find a plan or idea for one online, or maybe someone here can
tell you how to jury-rig one.

However, if the bed is too short to use the tailstock, it raises the
question of how long this thing is and how much of it you want to turn
down. A long, thin aluminum tube is going to present a deflection
problem, in which case you may have to rig a follow rest in addition
to the steady rest. You can look that one up, too.

It's about 12", 11" of it I need to reduce. I'm not to worried about
deflection, it just needs to slide in my bike frame tube, nothing
precision about it.
It's a seat post with a spring in it, I want a little more protection
for my compromised spine.

Thanks, Mikek

We once did a job similar to this. Make a "center rest" out of
plywood and a section of 2 x 4. Mount a drill bit of some sort in your
chuck and slide the "center rest" along the ways and mark the center.
Bore that to match the present diameter of the seat post. Stick the
seat post through the Center rest, clamp the center rest to the ways,
and chuck the last 1/4 - 1/2" in the chuck with the seat post clamp,
if any, hanging out past the center rest. Turn the post to diameter
and cut off the small original diameter section where you had chucked
it.

Depending on what your time is worth it is likely cheaper to just buy
the correct size (at least that is what I ended up doing :-).
--

Cheers,

John B.