Threading Piano wire

[Levanter]

I am just making up some wire U/C for the Mini Jazz. Building came to a halt for a while and I need the U/C in place to keep a running check on the C of G.

On the bent dural gear I have used Nylock nuts on the stub axles to retain the wheels with good results. I think they look better than collets and I reckon they are less prone to falling off.

If I heat the very end of the wire to cherry red keeping the axle section and the last bend cool with a heatsink will this soften it enough to make a thread. I am only talking about the last 6mm of the axle.

I think the wire is 8g

[Biggles' Elder Brother - Moderator]

The problem heating it is it will stay softer and you might spread the loss of temper further into the metal than you intended. I have threaded piano wire with a die - but it was very slow hard work, with plenty of grease and didn't do the die much good! I found the best plan was to use a cheap die that you didn't mind damaging - you get a reasonable thread.

BEB

[Peter Miller]

Forget it.

Piano wire is far too hard ro cut a thread into it. You will ruin your die

You might soften it but I think you will find that it will still not work properly.

Personaly I find the only reliable way of holding wheels onto piano wire is to wrap with copper wire and solder it.

Another good way but ore work. Take some 8 SWG tube a bit loger than the axle and solder it onto the wire. (You will have to drill ther wheels out) Then drill a 1/16" hole across the tube and use a 1/16" split pin.

[Cuban8]

Yes, have to agree. Putting a thread onto piano wire is very unsatisfactory - I've tried it in the past and only finished up with a shadow of a thread and even that seemed out of true.

Collets work perfectly providing a small flat in filed in the wire for the grub screw to seat on and a tiny drop of loctite is used to secure the grub screw to make sure. Resist the temptation to over tighten with the Allen key, often to the point of damaging the key or screw (we've all done it) you really don't have to lean on them to make them secure.

Don't flood the collet with loctite as it'll be a devil of a job to get it off later. Carefully applying a hot soldering iron to a loctited in grub screw will release it enough to remove it without ruining the screw or allen key.

[Stevo]

I'm with you Peter - I've never threaded it for those reasons. I always use the brass tube, washer and split pin method. Easy to remove the wheels should the need arise!

[Levanter]

Thanks everyone.

I like the idea of the brass tube and the split pin and will use this method. BEB has given me a glimmer of hope so I will experiment with the thread but NOT on the real job.

[Bob Cotsford]

I've threaded 8swg wire by heating the very end to cherry red then cooling slowly, doing the two legs on my Jungmeister killed a die for any precision use but the thread was good enough to take nylock nuts. As the die came from a cheap Aldi set that only cost a fiver I was quite happy to destroy it. The Jungie is over-engineered and overweight but the axle is still straight after several years so I guess it only lost it's temper over the small section heated.

[Braddock, VC]

If you have nylocs stuck in your mind, the more expensive option, but still cheaper than buying a die or dienut, Model fixings sell socket head screws with a 15mm plain shank then the thread to the end of the bolt. You can thread the wheel on, then an ordinary nut put the screw through the hole and pop the nyloc on. The alloy u/c is clamped between the ordinary nut and the nyloc one, A drop of cyno on the thread of the ordinary nut will keep it in line but always seal the wheel axle hole with vaseline or grease to prevent the cyno getting in.

I've used this method on a 120 size ultimate bipe and it holds the spats on tight too. In my case the unthreaded section of shank was too short but the wheels had alloy hubs so no excessive wear appears to have taken place.

[kc]

To prevent collet screws coming loose I found that Thixofix contact glue works well and is easy to undo them when needed. Much easier to undo than Loctite. Also works extremely well on silencer bolts too - never lost one in decades but always managed to unscrew them when necessary. Thixofix seems the wrong stuff for the job but it works well and you might have it in stock for other jobs like ply doublers to balsa joints.