I've done this with large bearings ( larger than 8" shaft dia.) too.
Heat quickly and move quickly before the therms move where you don't
want them to.  Try to keep your heat localized.

Jinx is right, you'll only need something like 0.001" interference fit
to get things locked.  Machinists Handbook has the classes of
"light-press" "med-press" and "interference" type fits.  This depends on
the diameter of the objects you are working with though.

I've seen this done with valve seats in engines too.  Expand the head
with a torch and shrink the seats with dry ice.  Seats drop in easily,
and once everything gets to the same temperature, the seats are locked
in.


On Sat, 2004-01-24 at 04:22, Jinx wrote:
> > As far as heating these things to red hot, that's probably not a
> > good option, as the parts are ridiculously tiny.  I'm hoping I can
> > use a heat gun to get it hot enough.
>
> Look up figures for thermal coefficient of expansion to get an idea
> of whether you can work with what you've got. A clockmaker friend
> of mine uses a small butane pencil torch to place steel pins and
> axles in brass chassis. You need only the minutest difference to
> get an exceedingly hard grip on cooling
>
> --
> http://www.piclist.com hint: The list server can filter out subtopics
> (like ads or off topics) for you. See http://www.piclist.com/#topics
--
Dan Devine

"Serving the public since....well, never"

dannyboy259@comcast.net

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics