I have a 4" stainless bar 4' long (That's just what I have laying
around). Cut a slot in the end of that for the tool holder. Just mount
that on the saddle and use it for a boring bar. The stock would need to
be 2' longer so the tool won't bottom out.
First, you mount the stock between the 6 jaw and "bull nose" use the
"set tru" to offset any wobble so the entire length fits in tolerance.
(sometimes you have to throw out a piece)
Then you skin the OD and put the steady on.
Do your boring job
Check for taper as you go. (albeit my boring gauge is about 17 inches
long you can still do it)
Go back to the bull nose and finish up the OD.
Use the cutoff tool to get your length.
That's about the best you can do on an engine lathe.
If you want better than that I would gun drill bar stock and find a 24"
inch piece of that that fit the bill and skin it.
If you need better than that! I won't go into it but there are still
other methods.
I have not tried Paul's method I must admit it sounds interesting. I
would make the surface finish very smooth to try that method to prevent
galling (because aluminum will gall) and I would use a torch on straight
acetylene and put a uniform coat of soot on the bar before shrinking the
aluminum to it.
I'd make some holes in the tube I could use to PULL the tube off the
bar.
That's my 50 cents
Monroe
-------- Original Message --------
Subject: [AR] Re: machining aluminum pipe
From: Paul Breed <paul@xxxxxxxxxx>
Date: Wed, December 05, 2018 8:59 pm
To: arocket <arocket@xxxxxxxxxxxxx>
Carl the way I would do this is to get some 8" OD steel pipe.
Weld Plates on the ends so I can be turned between centers on a lathe....
Turn it down to your Id.
Cold soak the steel with LN2....
Heat the aluminum pipe.....
Shrink the aluminum over the pipe....
(This will true up the pipe )
Now turn down the outside, leaving some beefy end on the aluminum pipe....
Now set up to pull the aluminum off the steel, IE Press or cable pull....
Put LN2 inside the steel and heat the Al, till it comes off...
No way that thickness of pipe is gong to stay true over 24" for turning...
If one had to do many many of these, I'd set the steel up with a slot that
had a machined piece go in....
IE Set up steel pipe in mill and machine opposing Tee slots on both sides
of length wise slot....
Machine piece for slot, drive into pipe....
Machine round, drive piece out of slot install aluminum reinstall piece in
slot... when time to remove aluminum drive piece out of slots...
Might also need parts inside pipe to pull both sides together to collapse
slot....
Turn down
On Wed, Dec 5, 2018 at 7:05 PM Carl Tedesco <ctedesco@xxxxxxxxxxxxxx> wrote:
All,
Does anyone have a recommendation for a shop (preferably in the Southern
California area) that can machine aluminum pipe (modify OD & ID and make
round)?
I want to take a 24” length of 8” diameter 6061-T6 pipe and machine the OD
to 7.708” with the wall thickness at 0.300”. A local shop wants to lathe
it from both ends, but cannot guarantee there will be a step in the middle.
Thanks in advance,
Carl Tedesco