Annealing music wire

Maybe it is just me... but some images of what you currently have would be really helpful in coming up with some different ideas or inspiration that you could ponder upon. I have some rough ideas of what your landing gear looks like from past descriptions, but that could be all wrong :)

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.

The washers won't come off when you want them to, and do come off when you don't. I'm thinking up a few schemes to do a nicer job, some of which would go a lot nicer if the steel were drawn a lot more than it is. I don't want to go using my nice 5-44 die on hard steel, nor do I want to try drilling .050" holes.

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. To just draw it, should I do something like filing a spot shiny, then heating it to blue or purple, then letting it cool? Or is there a better way to do this by eyeball methods?

Comments appreciated. I know how to make it work with rocks and sticks, I'd just like pointers on using hammers and screwdrivers for the job...

This is the "ugly" wheel installation, not even dressed up by using a proper set screw (those particular collars are metric, and I have no metric set screws). The only ones that are uglier use ugly wheels.

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?

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).

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It depends on the thickness. After seeing your photo, I'd say it probably will NOT quench in air. It looks like it's maybe 1/8" or so, right?

It's hard NOT to quench a piece of, say, 0.020" wire. But thick wire should be OK in air. To be safe, scrounge some ashes from a wood fire or a charcoal grill. I keep a 3-lb. coffee can full of ashes just for little jobs like that.

'Should be no problem to cool that in air. And, from the colors, you'll be able to tell hard far up the wire you've softened it.

Tim Wescott Inscribed thus:

Just an idea. Use one or a pair of heatsink insulators like those used for mounting power transistors and a dab of hot melt to secure.

I've suddenly got this insane notion to try drilling and tapping for 2-56 hardware -- I think I need to go lie down until the feeling passes.

Way back in my model airplane days (c. early/mid 60's)... seems like we would find (or make) a brass washer that fit snug over the end of the axel; put on the wheel, a thin 'shirtboard' type cardboard 'washer' to act as a spacer, then solder the on the washer with the soldering gun. Once cool, the cardboard spacer was torn out. If one were to mess with the axle length, find the right washer and really get everything super clean before soldering, they'd look very professional with the end of the axle not even visible. Last for eons too. You could even R&R the wheel assy without much trouble.

These were large control line models, and the axle's were probably on the order of at least .125"; maybe even a little larger in some cases. Wheel hubs were aluminum. I recall never having any solder other than

I recall neither collars or epoxy... well, some people might have been using epoxy back then, but certainly not for wheel retention. (Ambroid and white glue were the adhesives of the day, neither of which bonded well to metals.)

IIRC, some axel/wheel assy's required both inboard, and outboard washers.

Practice with some scrap first.

Good luck!

Erik

Hey Tim

How a bout using wire-nuts? Gives a nice sort of "streamlineing" to the wheels.

Brian Lawson XXXXXXXXXXXXXXXXXXXXXXXXX

I have found that filing a flat on the music wire will make it hold the collars much better. A little blue locktite finishes that job. Most of my music wiare landing gear has been 1/8" or 5/32" wire. Wheel pants go a long way to hiding ugly hardware.

BobH

I soldered them on back in the 50 & 60's too.

Carbide micro bit and a pin?

Or how about a light groove all around and using split ring retainer washers. (spiral plastic that will lock into the groove.)

Loctite (sleeve)bearing retainer would hold it..

Something like Loctite 638:

I should try it. Seems like I'd just succeed in melting my wheel hub.

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.

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.

With plastic wheels/hubs, I'd guess they'd melt for sure. You have to pour some good heat into that music wire. All my wheel soldering 'experience' was with rubber tired Aluminum wheels.

Erik

An aluminum hub would be no problem. Modern wheels are mostly plastic hubs (which is certainly nice and light), and most of those are probably the highest-quality styrene that can be had when buying from the lowest bidder.