Thick wire bending??
 

Debating on trying to bend the stock gear just a smidge on my BUSA DR.1 to make it both narrower and taller. I am thinking it is 3/16" and wanted to know the best way to bend a thicker wire as this. I assume putting it in a vise would be best? Also, should it be bent cold or heated up? The last thing I want to do is weaken the metal. The bends won't be much but they are prebent of course and I want to tweak that a bit.
Thanks for any insight!!!!

On another note, I will need to drill thru the 1/4" axle to retain my wheels with a cotter pin. I assume here it is needed to heat the wire red before drilling threw? After done, should I quence with water? Any special type of bit that would make this easier?

Regarding bending, I need to bend some 1/4" wire - I have ordered the K&S Engineering KNS326 Mighty Wire Bender & Coiler.

As far as I know you can bend music wire cold, though I don't know if you have to heat it to drill through it. According to information in this thread it's very hard, so you might.

The might bender will do it. It didn't have a clamp on it when I bought mine which meant the wire slipped and you had to account for where the bend actually ended up; A couple practice bends showed it always moved the same amount. If I'm not mistaken the mighty bender now has a built in clamp.

Either way it will bend 3/16" wire. I've done it without difficulty. Just don't yank it over too fast or you'll crack the wire. Bend slowly and it will work fine.

PS. No, you do not need to heat the wire.

Hi flygilmore
Drilling the axle so you can use a cotter pin is not the way to go. Most of us use a collar with a set screw to hold the wheels on the axle. I grind a groove into the axle so the set screw goes into the groove. This way the set screw does not need to be very tight. I always use Blue Loctite on the set screw threads.

If you want to use the cotter pin wheel retainer, the easiest thing to do is solder a piece of brass tubing over the axle and have it extend beyond the music wire. Then drill through the brass. IIRC BUSA shows this on the plans.

Harry Higley made very simple wire benders however his benders only go to about 5/32. All I did was to up size the tool to handle up to 1/4 wire. I used a steel block 1X2X3 inches and drilled and reamed appropriately sized holes to hold the size pin I wished to bend around. The radius of this pin will give you the radius for the landing gear. The bending pins should be a press fit in the steel block. You bend the wire cold and it retains all the properties it had without cracking or breaking. Bending it in the jaws of a vice and create a sharp bend and lead to breaking. By using a 1X2X3 block of steel I was able to place 4 different bending pins around the 4 sides of the block leaving two faces for clamping in a big vice. The web site gives you an idea how to go about bending the landing gear and getting rid of the deformations that can form on the wire during bending. Hope this helps.

http://www.harryhigley.com/14LandingGearWireBender.htm

Dennis

Definitely bend the music wire cold. I use a vise and slip a small diameter iron pipe (from the local HW store) of about 12" long over the end I'm trying to bend to get the necessary leverage. Always bend it slightly further than intended and lightly bump it back to the desired angle. If you don't have a vise, you can do it by having another iron rod with a hole drilled perpendicular near one end. Slip it over the music wire on side that would normally be in the vise. Starts to get hard to do without a vise for 1/4" and larger unless you've got good hand/arm strength.

And forget about trying to drill the axle. Both suggestions above are much better options.

For what you want to do just clamp it in a vise.

DO NOT heat the wire. It is spring tempered music wire & heating it will draw out the springyness.

I've done this lots of times. I recommend two washers between the cotter pin and the wheel. Use a nylon washer next to the wheel and a steel washer between the nylon washer and the cotter pin. You may be able to just use the nylon washer.

I put it all together the way I want it and then drill the hole for the cotter pin giving about 1/32" extra room so nothing binds.

I also drill the hole before soldering the tube to the music wire - it's just easier to work with.

if you do it that way you can just give yourself plenty of room and then cut the inboard part of the tube until you get the right amount of space between the wheel and the washer. Then solder the tube.

If you use a vise to bend your wire then I would line the jaws with hardwood which will make the bend less sharp (better). You'll need very hard wood for wire this thick - oak, hard maple, etc.

The drilling task you're talking about would require annealing the wire (heating it to red hot then letting it cool slowly) and then affixing a collar to it that won't move that has a hole through it to guide the drill bit. That will keep your bit from walking. It will be a royal pain to do and won't look any better than the brass tube method described above.

Thanks so much for the replies!!!

Looking back at my notes, on my first DR.1 I did heat the wire and drill through it and it wasn't so easy. I remember the brass tube trick now and will def. be doing that. Thanks again folks!!

What ever you do ... Don't heat the wire as it will become very soft and and will not carry its shape with any load applied! Could then be used to make a Clothes Hanger!
Leo

Others have suggested using a bench vice to bend the music wire landing gear. I have been bending landing gear using a vice for over 40 years. The following is EXTREMELY important. The vice naturally has sharp corners at the top of the jaws. At first I bent the wire over the top of the jaws and I saw no problems. Then, one day, the wire broke at the bend. It broke like a piece of glass. The break was very jagged. It could have ripped my hand. Now I always use a heavy leather glove on the hand doing the bending. I studied the reason why the wire had broken, and realized that the reason was that the wire was being bent over a sharp corner. When cold bending steel, the inside radius of the bend must not be less than the thickness of the material being bent. On my vice, I ground a groove, about 5/32" wide. I made the bottom of the groove rounded so that a bend radius of about 5/32" would result. If you do not want to cut a groove into the jaws of your vice, use a piece of hard wood for that purpose. I have offered this explanation many times of these forums. I do not recall ever hearing a comment on my explanation and have wondered if the reason is that no one believes me. Any comments or questions?

I just realized that the following statement may be controversial: "I studied the reason why the wire had broken, and realized that the reason was that the wire was being bent over a sharp corner. When cold bending steel, the inside radius of the bend must not be less than the thickness of the material being bent". I am a retired Mechanical Engineer, 78 years old, and I cannot remember I where I picked up that information. Perhaps a young engineer can refresh my memory.

absolutely right, and funny, I have the SAME sort of groove cut into the jaws of my vise (which is about 50 years older than I am :) )
I could not agree more regarding the glove and not to use heat.

personally, I learned that one from my Father... who was an old crew chief and pretty doggone good with bending LG wire.
I seem to recall that being mentioned (about 35 years ago ;) ) in A&P school as well..

Great tips - thanks everyone.

I couldn't tell you where you heard it Villa, but I can vouch that you are right. The bending process stretches the steel on the outside of the bend. The sharper the bend is, the smaller the amount of steel there is to take that stretch. Too much stretching causes surface fractures to occur (much more likely with hardened steel like spring tempered music wire than with annealed steel) which can then become a fail point. The wider the radius of the bend, the less chance there is of developing those cracks.

I'm younger than you by one yr. Villa. Did the same thing with my vice many, many yrs. ago. Welders glove and a big hammer shows it whose boss.:)

Gord.

Thanks for the input, fellows. I know people who would never treat their tools the way I do. If I can modify a tool, so with it I can do what I want, I do it. My vice is still serviceable for everything I want to do with it. When I bend thin wire, even wire that is not hardened, I use a special pliers into which I have cut grooves in the jaw to give the inside bend radius that I need so the wire will not break.

I used Z-bend pliars to put a bend in cold 1/16" music wire when making a push rod many years ago. After some use, the wire failed at the bend, causing heavy damage to the plane in an emergency "landing" with no elevator control. The pliars produce very sharp bends, violating the rules of bend radius by a wide margin. I too am a mechanical / aerospace engineer (now retired) - should have known better. Lesson learned and never forgotten.

Tools are often modified to suit a purpose Villa. Its common practice or was in workshops since cocky was an egg.:D
I agree with others here Always bend piano wire cold, dont anneal it (soften it) by heating, dont heat and quench it - that wont put the spring back but just make it brittle as glass or leave it soft like annealing. use a wheel collar or the brilliant brass tube + split pin idea.

Z benders are fine so long as you dont really squeeze the last bit out of the bends :D

More importantly Z Bend pliers do bend, at least the ones I have used over the years perfect z bend. Anyway you cannot over squeeze. That is unless one does not use the proper size and temper wire, never Piano wire. An example of which would be the Dubro threaded rod end wire. These are not 'piano wire' and much softer.

John

Why would you use piano wire for control rod?

Heat the wire to cherry and it bends like butter. If you bend it too sharp an angle cold you may break the wire or weaken it.

Andy