On 2011-11-17, Tim Wescott wrote:
On Thu, 17 Nov 2011 15:12:28 -0500, Ed Huntress wrote:

"Tim Wescott" wrote in message
...

I'm building model airplanes. Nearly everyone bends up their landing
gear out of music wire (0.9% carbon, low alloy, hard drawn wire), and
either holds the wheels on with these really ugly collars, or they epoxy
on washers.

[ ... ]

So: how to anneal, and how to just draw the temper a bit more? For
annealing I expect that I can just clamp the thing in my vise (both to
hold and to limit heat travel), get the end as hot as it'll get with a
propane torch, and let it cool.

[ ... ]

Anneal: Get it dull red, stick it in some ashes or powdered lime. Ashes
will be better with music wire. Lime might actually re-quench it, if the
wire is thin.

Draw: For music wire, drawing it locally, I heat a piece of steel rod to
red, lay it against the music wire; draw to the color you want; and
water-quench *fast*. If you're heating just the end and if you have an
electric stove top, you can just lay it on a burner coil.

Here's a color chart:

[ ... ]

(BTW, this is not the best way to anneal or draw plain carbon steel in
thicker sections. But the better methods aren't going to be very
practical with wire.)

So if I just heat it to dull red and let it air-cool, will that be fast
enough that it'll actually quench, even with it being carbon steel?

It might be. Certainly with it clamped close in the vise, you
will have a lot of cooling through conduction to the vise jaws.

If you're going to heat sink it in the vise, start by getting it
quite hot with the torch flame, then move the torch away and back for
shorter and shorter times back and longer and longer times away to
gradually cool it.

Strength in this spot is absolutely not an issue: the landing gear needs
to be very springy close to the center of the plane, with the needed
strength dropping off the closer you get to the wheel -- by the time
you're on that side of the wheel, it could no stronger than soft
aluminum, and you could safely retain it with a cotter pin and washer
(which is why I'm contemplating drilling little holes).

http://www.metalworking.com/dropbox/wheel.jpg

What size wire is this? I'm not sure how small a cotter key cna
be purchased. You might wind up having to make your own.

Good Luck,
DoN.

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