Subject: Re: stuck tapers

From: [email-masked] (Clive Washington)
Date: Mon, 10 Jan 1994 17:04:01 +0000

In article <[email-masked]>, [email-masked] (Philip G Isaac)
wrote:

> Can someone help with the "stuck-taper" problem?  I have two stuck 
> tapers which have not yet yielded to efforts to free them.  
> 
A last resort solution is to put a propane torch on it.  The idea is to
expand the outside (female) shaft before the inner taper expands, so 
use a large soft flame to heat the entire shaft, and be ready to knock the
taper out after about 30 seconds of heating.  The expansion should loosen
it,
and it will help free rust or old pitch deposits too.

It's a last resort because it might distort the shaft if it was machined
with some residual stress.  Use gentle well-distributed heating to try to 
avoid this.

---

From: [email-masked] (David Jenkins)
Date: 11 Jan 1994 11:58:19 GMT

In article <[email-masked]>,
[email-masked] (Clive Washington) writes:
|> In article <[email-masked]>, [email-masked] (Philip G
|> Isaac)
|> wrote:
|> 
|> > Can someone help with the "stuck-taper" problem?  I have two stuck
|> |> > tapers which have not yet yielded to efforts to free them.  
|> > 
|> A last resort solution is to put a propane torch on it.  The idea is
|> to
|> expand the outside (female) shaft before the inner taper expands, so
|> |> use a large soft flame to heat the entire shaft, and be ready to
|> knock the
|> taper out after about 30 seconds of heating.  The expansion should
|> loosen
|> it,
|> and it will help free rust or old pitch deposits too.
|> 
|> It's a last resort because it might distort the shaft if it was
|> machined
|> with some residual stress.  Use gentle well-distributed heating to
|> try to 
|> avoid this.  

Before trying a torch, try a hot, wet cloth on the outer taper, with
something cold on the inner (dry ice? or a salt/ice mix).  

Extreme heat is likely to cause distortion.

-- 

David Jenkins

* I'd rather be steaming... *

---

From: Doug White <[email-masked]>
Date: Tue, 11 Jan 94 09:35:33 -0500

> Extreme heat is likely to cause distortion.

One way to get something real cold, real fast is to use 'Quick Freeze'.
This is sold in aerosols at most electronics stores (Warning: Radio
Shack sells small cans for big bucks).  It is used to locate thermal
intermittents in electronic circuits.  It uses the same propellent as
photographic aerosol 'Dusters', only it spits out liquid, not gas.
If you can find dusters cheap, just turn the can upside down for the
same effect.  On a small area, you can drop to -40 C in a few seconds.
I have used this to unstick small tapers and to cool drill bits when 
drilling plastic.  The new stuff is supposed to be ozone friendly, but
it can be pricey to use in any big way.  A 12 oz. can is $7-$8.  I
haven't tried it for shrink fitting, but it should work on small stuff.

I don't have compressed air in my shop (yet), so I clean up most of my
chips (no fine dust) with a vacuum.  I keep a couple of cans of 'Duster'
around to blow out small holes, and flip 'em upside down for cooling.

Doug White
MIT Lincoln Laboratory

---

From: [email-masked] (James Kirkpatrick)
Date: 12 Jan 94 10:53:21 MST

In article <[email-masked]>, Doug White <[email-masked]> writes:

|>One way to get something real cold, real fast is to use 'Quick Freeze'.
|>This is sold in aerosols at most electronics stores (Warning: Radio
|>Shack sells small cans for big bucks).  It is used to locate thermal
|>intermittents in electronic circuits.  It uses the same propellent as
|>photographic aerosol 'Dusters', only it spits out liquid, not gas.
|>If you can find dusters cheap, just turn the can upside down for the
|>same effect.  On a small area, you can drop to -40 C in a few seconds.
|>I have used this to unstick small tapers and to cool drill bits when 
|>drilling plastic.  The new stuff is supposed to be ozone friendly, but
|>it can be pricey to use in any big way.  A 12 oz. can is $7-$8.  I
|>haven't tried it for shrink fitting, but it should work on small stuff.

A less pricey thing to try is the freezer in the kitchen.  Or, here in
Wyoming, throw it outside overnight!  It might take quite a bit of
quick-freeze to cool a lathe tailstock ram.  I'd suggest being careful
about rust caused by condensation regardless of cooling method.

|>I don't have compressed air in my shop (yet), so I clean up most of my
|>chips (no fine dust) with a vacuum.  I keep a couple of cans of 'Duster'
|>around to blow out small holes, and flip 'em upside down for cooling.

Some say cleaning with a vacuum is preferable in any case, since blowing
chips/dust around can cram junk into places it normally wouldn't go, as
well as merely re-distributing a mess over a wider area.

|>Doug White
|>MIT Lincoln Laboratory 

BTW, are you familiar with ancient computing at Lincoln Labs?  I think
we ended up with your old IBM 709 many years ago (parts, never ran it).