Villa

krosypal

Since you are criticizing me personally I wish you would at least read what I have written. At no point did I even hint that my method was the correct method(if there is a such a thing). I merely stated that by bending cold (after I learned to put in an adequate inside radius) I have never had a failure in 30 years or so, and that the performance was about the same as I had seen with bent landing gear wire on the many kits I have built. I also pointed out that I don't have the room or equipment to heat treat. I don't need assurance from anyone that my method works. I just look at my landing gear. I probably make 10-20 landings for every tank of fuel and use about one gallon every 2 weeks with .46 size engines. My gear experiences a lot of landings. It surprise me at how rude you are considering that you write like you have some education.

T_om

Wow. So much heat, so little light. (Pun intended).

First, to say that heat treating steel wire is beyond the capabilities of a home RC shop is silly. Of course it is not. And you do not have to be a metalurgist either.

Next, to say that all cold bending is necessarily bad is equally silly. Of course it is not.

As an amateur knife maker, I can assure you that anyone with even a minimum of tools (propane torch and color guide for common steels) and practically zero intelligence can sucessfully heat, anneal, and re-temper steel landing gear wire with no problems whatsoever. I prefer to bend steel using heat because it is so falling-down easy. But heat bending is not the only way to make landing gear for our toys.

Be very wary when you see absolutes trotted out in these forums as the *only* way to accomplish something. And be VERY wary of armchair experts everywhere, not just here.

Tom

rambler53

My Feedback: (494)

I read a comment written on RCU recently, "An expert is a person who has been at it 15 minutes longer than I have." I thought that was well said.

Don't take any offense Villa, rude is too vague for me to identify it when it happens. Forgive me. Enjoy reading and modeling guys.

(Psssst....heat it, dip it in oil, it's the right way.) Back to my armchair...I'm working on some more absolutes. Oh, drink a beer and laugh. It's the * only * way to read forums!

horace315

My Feedback: (15)

i watched a video of how wire landing gear is made and the same company makes it for almost all company's(made in china)they use different sizes of hardened steel piano wire and it is all squirted out cut and bent in a form in one step,the wire is unrolled from a large spool.no heat treatment done that i saw they packaged it further down the line.i would assume that you can get gear that is tempered after bending but it would cost a bit more.what we use it for isn't as critical as for commercial or private airplanes.i worked on a naval base where they make their own parts and they had their own foundry,most parts were made for submarines and i can say that the process they use was very critical.if you had to grade most of the metals we use in our models a metallurgist would fail almost 90% of it.i don't claim by no means to be an expert but for what i do my cold bending over the years has been sufficient for me and have had no failures.

1wrongbrother

I have always bent mine cold,while I am fully aware that steel when bent this way can and does crystallize, for all practical purposes I have never had a problem with my landing gears, then last week I went to bend a 5/32 one cold in the vise and it exploded in three pieces and it did not take much pressure, my guess is it was hardened too much, I then took a scrap piece heated it with a propane torch and it was so much easier to bend and get an precise angle, it did not seem to take the temper out too bad probably because I only heated it till it started to bend to avoid annealing it.

rambler53

My Feedback: (494)

So well said. No one really knows what hardness the steel they are working with will be, until it's too late. Safer to heat it, as you said, until it starts to bend easily, not red hot.

Larry S

My Feedback: (6)

Never did I ever expect this thread to become so "hot". I am an older modeler who has been at this hobby for over 35 years, fly mostly warbirds and I'm still learning. The day I stop learning is the day I die. I've bent music wire about everyway possible. I found heating it cherry red, bending then rapidly cooling the metal to be the easiest way but maybe not the best way. Easy to understand why heat it but cooling the metal?? How did I learn this, watching TV and seeing how somebody who does this all the time does it but I failed to catch how he got the hardness back into the metal. I had thought by rapid cooling would do it, it doesn't, that I know by how my gears behave. I've found that the gears I've heated bent easier then the ones I didn't heat. Also the other day, the 5/32 gear that I made and heated and was on my Ultra bent way to easy, even on soft landings. So I took it off the plane and went to bend it back into shape, it snapped in my hand. Now this was a home made gear, first heated, then bent, then rapid cooled in water. That was when I started this threat, there had to be a better way and Dr1 told me about the K & S bender. Well I had already ordered it and when it came in, I took a piece of K & S 3/16 music wire, looked at the picture on the box, and bent two of the niceness landing gears you would want to see. Ahhh, the test came today. I flew the plane today and because of water on our field, you had to make almost carrier landings to stay on dry land and was over a paved surface. Well the plane came in, did a little bounce off the dry area of the paved surface and rolled out onto the grass area where it finally hit some tall grass at the end of the field. Yeah, you're right, it was crazy to fly today. I had less then 1/10 of our field to use for landing and I had to take off in the parking lot. AMA didn't hear this. Result on the gears, they remained exactly the way they were before the flight, not bent at all. All I had to do was dry off the plane and take it home.
Cold bending without having the tool to do it is a pain. Heating makes it easier to bend but looses strength. It seemed like rapid cooling after bending the gear cherry red made my smaller, 5/32 gear both brittle and easier to bend simply because the more times it bent on landings and then being straighten out, the weaker it got to finally, it broke. Now remember, I used two different sizes of wire here but in the past I have found that 3/16 after being heated was weaker in the long run. This is probably because I don't know how to get that strength back into the wire after hot bending. That's the reason for this threat, for me to learn something new.
Merry Christmas guys and PIECE !!!
Larry

1wrongbrother

Just my opinion but I would think that if wire is heated to the point it glows orange it is already anealed just as when heating cast iron, further is it really necessary to heat it to that point.

Larry S

My Feedback: (6)

1wrong,
First I'm not sure what you mean "anealed" or even what "anealed" means. I've heard it used several times but never really understood the term. Now if you were to say "stronger", "weaker", I would understand. Second, you ask is it necessary to heat it to that point so I take it you never bent music wire by heating it or you would know. Let me put it this way, I had to heat the metal to the point where it starts to bend, and that was when it was starting to glow red. As I bent the wire, I slowly moved the point of my torch along the wire as it bent, maybe no more then a 1/4 inch. When I had the bend I wanted, I would take it off the vise and dip it in water. Now PLEASE don't take this as being the right way to bend music wire, it was MY way and I started this threat to ask if there was a better way.
So 1wrong, yes, I had to heat it to the point it started to glow to get a nice bend. The only problem I found doing this way was the wire would then bend easier without heat and after bending a gear on landings and straighting it again, it got to a point it would snap in two. Remember, this was with K & S 5/32 wire.
I decided to go with a heavier wire, 3/16 on my next set of gears for the same plane that had 5/32 wire simply because the gears are long and they flexed more then I wanted just taxing and bent after every landing no matter how nice a landing I had. On some of my warbirds I use a short piece of 3/16 wire and a oleo strut to absorb shock and I have had those short pieces bend, BUT they were first bent doing it with heat. Next time I'll cold bend them in the K & S bender and see what happens. My findings so far on the Ultra is that cold bending kept the strength in the wire but please remember, there may be a better way of hot bending and keeping that strength and we heard some excellent views on how to do this. Whatever works for a person, that's the way to go. There is no right or wrong. That's what this tread is about.
Larry

horace315

My Feedback: (15)

Annealing is a technique used to recover cold work and relax stresses within a metal. During annealing, small grains recrystallize to form larger grains. In precipitation hardening alloys, precipitates dissolve into the matrix, "solutionizing" the alloy.

Annealing typically results in a soft, ductile metal. When an annealed part is allowed to cool in the furnace, it is called a "full anneal" heat treatment. When an annealed part is removed from the furnace and allowed to cool in air, it is called a "normalizing" heat treatment.

Larry S

My Feedback: (6)

Horace315,
But what happens to the metal when I heat it red hot to bend and cool it in water? Would I better off to let the part air cool? I "think" I understand what you're saying and please correct me if I'm wrong. By letting the metal cool "in the furnace", I take that you mean, let it cool slowly, am I right? But I have found by doing it that way, the metal is weaker now then it was before I bent it. Like I had said sometime back, I watched a worker on TV heat a piece of metal up, do his work then submerge the piece in water to retain the stiftness it orginally had. Matter of fact it just came to me, the guy was making a sword. Now that's a weapon that should take a lot of banging againist other swords and not bend or break.
Now I got from landing gears to swords but the process of altering metals I would think would be the same. The more I think about something, the more I think I may be wrong and that is after cold bending, lets say a 3/16 wire, the wire would be very strong, less likely to bend BUT more pron to break then bend. Is that right? What if after cold bending I heat the metal, would it revert back to where it was before I bent it? And if it did revert back, how would I know how much heat to apply?
Larry

MinnFlyer

My Feedback: (4)

I still recommend cold bending - and here's why:

True, the BEST way to do it is to heat and quench - HOWEVER, both the heating AND quenching must be done properly.

You cannot heat an area of the steel, bend it and quench it without affecting another part of the steel.

If you are going to do it, the steel must be heated, bent, and then the ENTIRE piece needs to be heated to the proper temperature (Specified by the type of steel and the desired temper) for the proper LENGTH OF TIME (Again depending on material and temper) and THEN quenched properly (Ditto) And possibly re-heated to desired temper.

So here is the bottom line.

Cold bending: Not Idea, but fast and reliable

Heated bending without quenching: Anneals the metal to a soft state which will bend under most landing gear applications

Heating and quenching: Best way, but time consuming and MUST be done properly to achieve desired results.

Now... It is true that doing a so-so job of heat treating may not be perfect but can still achieve a usable gear, the same can be said for cold bending.

However, there is a better chance of screwing up the temper when using heat.

Therefore. I will stick to cold bending.

MinnFlyer

My Feedback: (4)

Larry S:

An easy way to understand annealing is to look at it this way:

The ring on a Padlock is hardened steel. If you try cutting it with a hacksaw, about all you will do is polish it.

Now take a torch and heat that ring till it's red hot. Once it's red, slowly pull the torch away so that the ring slowly loses it's red color.

Once you turn off the torch, let the ring cool to room temp.

Now you can cut it with a hacksaw.

To bring the ring back to a hardened state, it must be properly heated and quenched (Cooled rapidly)

Larry S

My Feedback: (6)

MinnFlyer,
Ahhhhhhhhh, a man who knows how to explain annealing for someone like me to understand. Thank you. And thanks everyone, a lot of knowledge has been brought out. So I wasn't to far off. I believe the biggest problem I had was getting a "nice" bend and I wasn't doing that without heat. I had tried to bend music wire by just putting in the vise cold and giving it the old heee ohhhh. What I would end up was a crappy looking piece of s)&) and that's if I was lucky enough to not break it. Then I went to heating the wire to bend and that worked ok, until that hard landing bent it worse. Thennnnnnnnn I tried the heat and rapid cooling method and that worked even better. But I was still looking for a better way and I came on the K & S bender so I gave it a try using a larger wire then I was using before and darn, did it work nice. The trick I can see is before I would just bend a wire and hope it was fairly round but with the K & S bender, there is a small rollar you bend around to keep the shape while bending. I've found this so far to be the best way to bend music wire without any hassles of heating, cooling , etc. IF I decide to have a sword made, I know a few guys here I'll have make one for me, they know their stuff.
Thanks guys, Larry

Bax

My Feedback: (11)

Kit manufacturers cold bend their wire (at lease WE do!). The metal is bent around a post that has the same radius as the inside radius of the bend. A long lever goes over that post and has a post on it that is spaced away from the center post exactly one diameter of the wire to be bent. The lever is long enough so that a person can easily bend the wire. The wire is not clamped. As you bend, wire will be drawn from one side or the other...it's pulled around the curve.

Various guides, stops, pegs, ramps, etc. are made so that the wire can be repositioned to make a series of precise bends. The bender used also has the correct amount of movement in the pulling lever so that the wire will be at the exact bend angle when all tension is released.

A shear is used to make a clean cut in the wire.

In my experience, clamping the wire in a vise and using a hammer to help bend it will only result in broken wire. The metal must be allowed to flow as it's bent...yes, even cold metal does flow a bit when it's being stressed (bent, in this case). Hammering work-hardens the wire and makes it even more brittle.

Dr1Driver

Good points, Bill, and thanks for the expert advice. Cole bending can be done easily, safely, and can result in a quality product, IF some protocol is used. As you state, hammering is out, as is bending too sharply or quickly.

Dr.1

horace315

My Feedback: (15)

Quenching is the act of rapidly cooling the hot steel to harden the steel.

Water: Quenching can be done by plunging the hot steel in water. The water adjacent to the hot steel vaporizes, and there is no direct contact of the water with the steel. This slows down cooling until the bubbles break and allow water contact with the hot steel. As the water contacts and boils, a great amount of heat is removed from the steel. With good agitation, bubbles can be prevented from sticking to the steel, and thereby prevent soft spots.

Water is a good rapid quenching medium, provided good agitation is done. However, water is corrosive with steel, and the rapid cooling can sometimes cause distortion or cracking.

Salt Water: Salt water is a more rapid quench medium than plain water because the bubbles are broken easily and allow for rapid cooling of the part. However, salt water is even more corrosive than plain water, and hence must be rinsed off immediately.

Oil: Oil is used when a slower cooling rate is desired. Since oil has a very high boiling point, the transition from start of Martensite formation to the finish is slow and this reduces the likelihood of cracking. Oil quenching results in fumes, spills, and sometimes a fire hazard.

IMO cold bending is the best way for the materials we work with.spring carbon steel has a memory to it,and will try to return to its original shape someone here said bend past the shape that makes a lot of sense,most of the landing gear wire we use is only surface hardened and can handle a lot of flexing.case hardened metals are too brittle and will shatter when stressed.when piano wire is formed it is pre stressed so it can be put under pressure and hold its orginal shape year after year.

Larry S

My Feedback: (6)

Thank you Bill,
does help when info is from a manufactor. Matter of fact, I just returned from the post office after mailing a Accu-Cycler to your exact address to have fixed. They said you should receive it tomorrow. I'm just up the big road a piece from you, 10 miles north of Kankakee. Hope it can be fixed but if not, time for a new one.
Larry

Farmbuyer

For those interested, a budget (but very effective) gunsmithing method of tempering spring quality steel after the annealing and bending stage is to completely submerge the cooled off spring in a pan of used motor oil. Heat the oil with a propane torch until it is hot enough for the oil to burn on it's own until the oil is completely burnt off, keeping the heat on if neccessary for the oil to burn. Let air cool and VIOLA!, a spring that works or doesn't. In th case of a gun flat spring, one compression in a vise will tell. The science behind it is that motor oil burns at around 700 F which is the proper range, and apparently time, for tempering spring steel. I personally have not tried this but have every reason to believe it is a respected method since it is explained in GUNSMITH KINKS, the gunsmith's bible. Here is a link with an example. [link]http://www.midiowa.com/toadhallrifleshop/springs.htm[/link]

I keep reading about the use of used motor oil for the quenching and in this case the tempering. I am guessing that it has to do with more carbon content than new motor oil?

Greg

Hughes500E

My Feedback: (16)

So how the hell do we silver solder music wire now after all this

MinnFlyer

My Feedback: (4)

Just don't let it get red

Hughes500E

My Feedback: (16)

Dr1Driver

That's right, MinnFlyer. Get the joint perfectly ready BEFORE applying any heat. Heat the joint until the solder JUST flows, then remove the heat. The silver solder we use melts below 500 degrees F, below the annealing temperature of most hardened steels. Use enough heat to get the job done quickly. A torch, iron, or gun that's too small will hold the metal just below the solder's melting point for a while, possibly altering the temper. Heat it quickly, do the job, and remove the heat. Molecular change will not occur in that short of a time.

Dr.1

BruceTharpe

My Feedback: (1)

I'm firmly in the "cold bending" camp. I worked for Sig and can tell you first-hand that they have been bending all their wire cold for over forty years.

I also love K&S wire benders and use them often. However, the coil bender has a design flaw IMHO. The handle has a grooved post that engages the wire, but it is too tall. When you come around with the wire, the post will bump into the very wire you are trying to bend and results in gaps between the coils. Normally, you want the coils side-by-side with no gaps. I modified my bender by simply grinding down the height of that grooved post so that it won't interfere with the coils as you are bending.

Larry S

My Feedback: (6)

Thanks,
good tip. I haven't as yet tried to bend coils but if and when I have that problem, I'll your tip in mind.
Larry