Bend Allowance for Music Wire

[Motorman]

I was putting some S bends in 3/32" K&S music wire for push rods and got pretty good at making the bends tight but the wire would snap in half sometimes. Made me wonder if there are recommendations for bend radius on music wire.

MM

[Tim Wescott]

Bigger than you were using.

Do a search on "Wire bending radius".  There's standards out there.

I try to bend the wire around a pin that's no smaller than the wire in question, and is preferably 1.5 to 2x as big.  But I've been told by experts* that I'm no mechanical engineer.


* Prototype machinists: "your drawings are much too good, you can't be a mechanical engineer".

[Motorman]

Do a search? doesn't this count?

[Tim Wescott]

Do a search? doesn't this count?

http://lmgtfy.com/?q=minimum+wire+bend+radius

[Randy Cuberly]

I seriously doubt you will find very much on the minimum bending radius of music wire.
I can tell you that as a general practice the inside bend radius should be about 2 diameters of the wire.  However that's not always practical.  Much smaller bends than that can be tolerated if used in a low stress environment.
I would also mention that a lot of the stuff we buy as music wire for modeling purposes is not very well controlled and I've personally seen it run the gamut from as soft as mild steel to to more than 60 Rc.  The soft stuff is easy to bend and will take a much smaller bend radius than the hard stuff.  I mentioned 60 Rc because a number of years ago I had trouble with bends breaking during the bending process and tested them at Raytheon and found that hardness.  At that hardness level the wire wouldn't tolerate even 3 diameter radii bends without breaking.
So unless you actually buy music wire that is certified as such, it's a crap shoot!

Fortunately most of the stuff around is tolerable...I Think!

I would also mention that for most of our applications such as push rods etc., High tensile wire like music wire isn't necessary.

Randy Cuberly

[Perry Rose]

Try annealing the end first. You can use ball links if that fails.

[Avaiojet]

My suggestion would be to use all Tom Morris hardware. You won't have to make another bend.

All ball links and CF rods. Here's his e-mail:

ctmorris@cableone.net

Please tell Tom that Charles recommended him.

[Kim Doherty]

I always heat my wire to cherry red and then bend. This lets me peen the bend tight with no worry of it breaking later on. Do not worry about the wire losing its hardness. It is way over hard for our application anyway.

Kim.

[Brett Buck]

I always heat my wire to cherry red and then bend. This lets me peen the bend tight with no worry of it breaking later on. Do not worry about the wire losing its hardness. It is way over hard for our application anyway.

  It's certainly not overly-hard for landing gear, and it should not be heat-bent if that's your goal, because it will end up far too soft.

   It may be OK for control horns, but those are best made of air-hardening drill rod instead of music wire anyway.

   Brett