On Sat, 09 Apr 2011 18:27:27 -0400, Ed Huntress wrote:
"Tim Wescott" wrote in message
...
On 04/09/2011 02:19 PM, Ed Huntress wrote:
"Tim wrote in message
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On 04/09/2011 10:20 AM, Ed Huntress wrote:
"Tim wrote in message
...
On Sat, 09 Apr 2011 12:41:01 -0400, Ed Huntress wrote:
"Tim wrote in message
...
On Sat, 09 Apr 2011 00:32:29 -0400, Ed Huntress wrote:
"Tim wrote in message
...
On Fri, 08 Apr 2011 23:16:17 -0400, Spehro Pefhany wrote:
On Fri, 08 Apr 2011 23:08:55 -0400, Spehro Pefhany
wrote:
On Fri, 08 Apr 2011 21:38:25 -0500, the renowned Tim Wescott
wrote:
I want to make a bunch of identical molds, for 3/4" diameter
model
airplane wheels.
I'm envisioning a tool that's 3/8" across, that I just
sharpen up,
grit my teeth, and push into a spinning piece of aluminum to
make
my desired profile.
Is this a sensible thing to consider? Is there some other
way (short of CNC machining) to easily duplicate cavities in
the ends
of a bunch of aluminum tubes?
Since you got me started on this, g here are two other things to
consider.
The other point, about your workpiece material: It looks like you're
machining wrought barstock, probably 6061 or 2024. I don't know the
figures for 6061 but in 2024, the thermal conductivity in the T3 or T4
state is roughly half that of the same material in the annealed state.
I'm sure you won't be annealing the material just from heating the foam,
but if you have in mind to anneal the tool first, to get better
conductivity, keep in mind that the material will revert to the tempered
state in a couple of hours if you don't give it a full anneal.
Neither of things probably matter, but I hate to leave details hanging
around, just in case. d8-)
It is, indeed, 6061, heat treated to some three or four-digit code with a
"T6" at the beginning. So I'm assuming that for my purposes it's T6.
I'm mostly thinking of heat conductivity in competition with plastic or
wood. Since the current process involves clamping up one mold with a
pair of vice grips and tossing the assembly in the oven for half an hour,
I can't claim that speed is of the essence. Before I start worrying
about the thermal conductivity of the aluminum I should think about
better ways to conduct heat _to_ the aluminum, like fins and a fan in the
oven, or immersing the mold in boiling water, instead of putting it in a
still-air oven.
I'm still tickled that I can make a wheel for a 7-gram rubber power plane
that barely registers on my 100mg-per-step scale -- it'll take me a while
to get past that.
--
http://www.wescottdesign.com