bugsymalone

I am converting my Tiger 60 to a float plane. I have adequate floats, but need to fabricate my own 13/64" wire landing gear. I gotta' think I need to harden and then temper the wire after bending it to the shape I need. Can a someone walk me through this process? Do I heat it with a torch to cherry red, then immerse it in water to harden the steel wire, then bake it in an oven to temper it? What temp for the oven? Is cherry red too hot? An iron smith I aint! Thanks for your input everyone!

Rodney

I'm afraid you will be sadly disappointed if you try to re temper any wire that you have heated to make bending easier. You will have best results using music (often called piano wire) wire and cold bending it. Without some very good temperature and mixture controls, it is almost impossible to re temper this wire in the home shop. Invest in a good wire bender as it is also quite difficult to do these bends with a vice and pliers and hammer. I have cold bent up to 1/4 inch wire (with great difficulty and a few errors) but it is possible.

MinnFlyer

My Feedback: (4)

Ditto to what Rodney said

da Rock

DITTO of MinnFlyer's ditto of Rodneys very good advice.

Roby

This subject has been covered many times. Do a search
on bending music wire. You'll find what you'll need.

It's fairly easy if you know what process to follow and
what to look for.

Regards,
Roby

Gray Beard

My Feedback: (-1)

Dito, Dito Dito and one more Dito for me too!! After I came up with the bright idea of heating and bending my wonderful new wire landing gear I was very impressed with myself for getting everything so perfect. Then I tried to land on my nice new gear, both axel bends broke right off!! Seems it removes the temper right away so you have to bend cold.

Lnewqban

Just bend your wire cold; better with the proper tool-bender.

Find some of the resons here:

http://www.djaerotech.com/dj_askjd/d...musicwire.html

KW_Counter

Is it really necessary to use music wire to make the floats mounting frame?
Why won't softer metal rods work? I am talking in the 1/8" diameter size.
Thanks,
KW_Counter

MinnFlyer

My Feedback: (4)

Soft rod will look great... until you try to take off or land.

A few years ago I reviewed a Nitromodels P-38. It had soft, 1/4" wire landing gear. After only 2 (gentle) takeoffs and landings, the gear had bent so badly that the props were touching the ground

Roby

Try this

Regards,
Roby




Heat Treating Music Wire - by Roy Vaillancourt

The music wire used by modelers to make landing gear and cabin struts is medium carbon steel heat-treated to spring temper or about 45 on the Rockwell C scale of hardness (RC45). On this scale,RC20 is soft,RC45 is tough,and RC60 is hard. Tough wire can be bent and cut using the proper tools and techniques, but sometimes it's just too difficult to work with.

One way to soften steel music wire is to heat it, which makes it easy to bend and form. But after heating and form- ing, the subsequent cooling often at an uncontrolled rate can make the finished wire too hard or too soft since its hardness is determined by the rate at which it cools. For some parts, the final hardness isn't critical. But a land- ing gear formed from wire softened too much won't spring back to its original position; and a gear made from wire cooled to a harder than normal state will snap on its first use. To restore the wire to its original specific spring temper, it must be heat-treated a second time and cooled at a controlled rate.

To form wire easily, first anneal it; next, form or bend it to the desired shape; and then heat- treat the part back to spring condition that is, temper it. First the wire should be annealed at the location to be bent. To anneal it, heat the wire with a torch until it becomes a bright cherry red about 1400 degrees Fahrenheit. Let it cool completely to the touch. Don't quench it or blow on it. Just let it cool naturally away from any drafts. The wire should now be in the RC25 soft range, and it will bend easily. After forming once again heat the wire with a torch until it becomes bright cherry red, but this time quench it that is, cool it rapidly by immersing it in room tem- perature water. Plunge the steel into the water with a twisting, swirling motion to keep water vapor from insulating the wire against the cooling action of the water.

At this point the wire should be very hard, probably above RC60. To test the hardness, try to make a mark on the worked area with a file. The file should slide off without cutting into the steel at all. If it cuts the wire, try the heat and quench cycle again. If the file still cuts the wire, it isn't high carbon steel. Get another piece of wire and start over you won't be able to add the neces- sary carbon to low-carbon steel.

When the file test signals success, the wire is ready for the final step, but not for use, because it's very hard and quite brittle, and will probably snap off. The final step is to temper the wire back to the desired hardness. Tempering is a form of annealing but is controlled so that the steel achieves a specific hardness.

Start by sanding the wire with steel wool or emery cloth. Then heat it gradually with the torch. Watch for the following colors as a guide:straw color (350 degrees), followed by dark blue (600 degrees), and then medium blue (750 degrees). At this point, remove the wire from the heat and allow it to cool slowly. Don't quench it or blow on it; just let it cool naturally in still air. Once the steel returns to room temperature, it should be at the target RC45 hardness, which has a good spring temper.

Try the file test again. You should be able to make a mark now, but only with some effort. If it passes this test, the wire is properly tempered. Besides parts for model planes, tempered music wire can also be used to make special pur- pose tools. Instead of tempering to 750 degrees (medium blue), stop at the straw color stage. The wire will be at about RC60, which is still very hard, but not brittle. Wire at this temper can be used to drill wood and plastics, and most aluminum and copper.

Notes
1. Rockwell hardness testing, named after Stanley Rockwell who made his first testing machine in 1921, is a gen- eral method for measuring the bulk hardness of metallic and polymer mate- rials. Although hardness testing does not measure performance properties, hard- ness correlates with strength, wear resis- tance, and other properties. Rockwell hardness testing is an inden- tation testing method. An indenter is impressed into the test sample at a pre- scribed load to measure the material's resistance to deformation. A Rockwell hardness number is calculated from the depth of permanent deformation of the sample after application and removal of the test load. Various indenter shapes and sizes combined with a range of test loads form a matrix of Rockwell hardness scales that are applicable to a wide variety of materials. The Rockwell B and C scales are used for metallic substances.

2. Anneal:To heat and then cool (as steel or glass)usually for softening and making less brittle.

3. Quench:To cool (as heated metal) suddenly by immersion (as in oil or water).

Hid

MinnFlyer

My Feedback: (4)

As a former machinist I knew all of this.

But why go through all of the trouble of heat treating and tempering (and believe me, it is a lot of trouble) when you can just bend it cold?

Lnewqban

Besides, there are the altrenatives of fiberglass, aluminum, carbon.

da Rock

If the entire gear isn't treated uniformly there is a probability there will be differences here and there.

Know anyone who can uniformly heat something that's probably 7-8 inches long best case? and might be 15-16"?

Gray Beard

My Feedback: (-1)

Photos, 3/16 music wire being bent. First by hand then I gave it a whack or two with a hammer just because. Nuff Said!!!

Charlie P.

I never heat piano/music wire. A good set of Harry Higley jigs for up to 5/32" and a K&S Bender for the big stuff and you'll be all set.


Oh, and a few whacks with a hammer just because.

bugsymalone

Thanks to everyone! This has been a real learning experience. You have all given me much to investigate. Thanks again for all your valuable input. Happy flying, and more importantly Happy Building!

da Rock

If you're going to bend piano wire in a vice, take a look at GrayBeard's post a couple above this one. Look closely at his vice jaws.

If you attempt to bend piano wire in jaws with 90degree corners, it will weaken the wire. Often the wire will snap when bending. The sharp edge of the jaw is the culprit. If you file the edges round like GrayBeard has done the bends will be strong and reliable.

MinnFlyer

My Feedback: (4)

Yes, having that divot in the jaws is critical... especially on heavier wire.

for 3/16" or heavier, I bend the wire about 75 degrees and then let it sit for an hour or so to let the molecules settle down before bending the last 15 degrees

Roby

A suggestion to anyone who may be willing to
spend a whole dollar and maybe learn something.

Buy a piece of music wire , (any size)and at least
try the procedure I provided at post #10 . It isn't
very difficult at all and should give you good results.

Even my grandson has done this.

Regards,
Roby

bugsymalone

Excellent information. Thank you Roby. I'm going to try it!

Roby

Great !!!!!!!
You just made my day.

Regards,
Roby

Gray Beard

My Feedback: (-1)

I agree with mike completely. I know how to heat treat but without a heatig oven {even with a heating oven} it's just too easy to bend wire by hand without the fuss. I can't beleave Rock spotted the filed grooves in my vise, there are a couple of them for different sizes of wire. I had the Higley jigs but they grew legs a long while back, talk about cool little tools and easy to work with. I still have my three prong wire benders from my dental lab days but I can only use then on very thin wire but they are great for the little control rods for electrics. One tool I would like to have on hand but have never gotten around to getting one is the Z-bender, another good little tool for electric pilots. So many cool ways to do something but I really like my vise and a hammer whacker!!

da Rock

Got them in my vice. Great for cold bending. I figured out their necessity how? You betcha.........

I've also got a hunk of iron that I place against the wire. Then I whack.... uh..... tap the iron to bend the wire with less chance to develop that very slight curve that happens every so often. Tapping seems to work great. A blacksmith said that hitting with just enough force works best. The iron solves the problem of inaccurate hammer hits and gets the impact down near the bend. I've heard someone say that the controlled hitting would "worry the metal" into going where you want it. I've always liked that concept.

Roby

I can understand how using the brute force method of
bending wire less than 5/32 can be made to work.

How well does the hammer tapping work on 3/16
and 1/4 inch ?

Regards,
Roby

da Rock

As with almost everything, you match the method to the material.
Your method can include different tools as well as different techniques. Matter of fact, it can include more than one technique in any single job.

People have been known to use a larger bending bar, or a bigger hammer, that is, when they were using bending bars or hammers.

But I can't answer your question about the 1/4" wire as I've never needed to bend any. But I've bent stuff with a bending bar that went easier with a piece of pipe over the bar to get better leverage.

BTW, the hammer is more often used to straighten the slight bend I get. I usually start with a bar. don't always need both, but each does good work for ya'.