tazzzz

i want to thread a 2-56 rod for 2-56 clevis what size die is compatable. I really dont want to solder this . TAZZZZ

guver

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2-56 Am I missin' something here?

frequent flyer

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A Die doesn't really work because the threads are rolled not cut on the rods we buy. You would have to get a larger rod for the 2/56 Die to work.

kwblake

Hey tazzz. For under 1/4", a number system is used. One size under 1/4' dia. is a #12. This has an approximate outside dia. of .216" . The next size down, is a # 10, with a dia. of .190, and so on, down to a 0000 which has a dia. of .021" Try using that tap.

Anyway the next number is the threads per inch. Example, is what you are after, has 56 threads per inch, which is the coarse thread. A number 2 screw also comes in 64 TPI, which is fine. So, anytime you see this ( 5/16- 18, or 2- 56) they are giving you the OD. of the bolt or thread, and the number of threads per inch.

Hope this helps a bit.

kwblake

Yea. I just went and measured. A rod that has #2-56 thread is approx. .070" in dia. To cut a #2 thread, the rod should be between .081 and .085. With a rod of .070 and the minor dia. of the thread being .063" in dia. , you will only have about .003" of thread depth. About the thickness of a human hair.

Villa

You have to purchase a 2-56 die. The number 2 is the Machine Screw size designation, and 56 is the number of threads per inch. The correct diameter of the rod is 0.086 inches. This is derived from the formula (# X 13 + 60)/1000), where the symbol # is the Machine Screw size designation, which in this case is 2. Since most of the 2-56 servo control rods purchased at your local hobby store today use rolled thread rather than cut thread, using that particular rod for threading 2-56 thread can lead to a very dangerouse condition, because it is subtantially less than 0.086 inches in diameter. The thread will be very shallow, and the clevice may easily fall off in service, which may cause your plane to crash. This happend to me once. If you have questions/ comments, please post them here.

Scar

My Feedback: (3)

The reasons they roll the threads on those rods are,

the rolling process introduces compressive residual stress in the threads, increasing the strength / making them less likely to break at the threads, and

the OD of the rolled threads is larger than the rod, allowing the use of a larger, standard size threaded clevis.

Cutting threads on a rod like that will add stress risers (notches) which are less sturdy than the bare rod, and the thread size will be very small, not a standard size.

There are lightweight carbon fiber rods available, if you're trying to save weight. If not, best to use something standard.

For small models, it is completely all right to use "L" bends at the ends of the rod, or "Z" bends. A wide "Z" bend is usually placed in the middle of the rod somewhere, to allow length adjustment.

Best wishes,
Dave Olson

Gray Beard

My Feedback: (-1)

There once was a company that made a great system for cutting your own threads for 4-40 and 2-56 called RODCHUCK. Back in 03 the cost of the system for 2-56 was $44.00.
Great tool but you better need to cut threads in a lot of wire to pay for it!! You used 3-32 rod to cut the 2-56 threads.. $44.00= a lot of pre-cut rods and solder clevises. I have see the system at a show but have never known anyone that has bought it.

tazzzz

Thanks guys for all the great info,,,got it written down,,,, HAPPY NEW YEAR TO YOU ALL!
TAZZZZ

bob62

My Feedback: (28)

I am sure glad we have such smart people on this posting blog

kwblake

Hey tazzzz. As Dave Olson said, it is best to use the existing thread, and a bend on the other end. Different length of rod, ( with a thread on one end ) will be available at your local hobby shop.

tazzzz

Thankyou sir,,,,,BTW Iwas up to Cornwall the other day,,,man it sure is cold up there 12 below,,how do you guys do that? I deliver Hazmat materials all over the country and usually in the niagara falls,not so far up. Well,,Im headed to LA tuesday,,hopefully to thaw out.


thanks for the help
TAZZZZ[:@]

kwblake

-12 C for us in Manitoba, in January is warm.

rc34074

My Feedback: (5)

I bought the RODCHUCK system and used it to make 4-40 threaded pushrods for my 81 inch mustang and a couple of other club member planes - at the time I couldn't find 4-40 pushrods the right length for this plane so it was a good way to get the pushrods I wanted. They still work fine today. This system is designed to make pushrods from standard inch diameter wire not wire made to precise threading OD specs, so the welding rod was just the ticket for that.

Ed

DustBen

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Keeop in mind when hand cutting threads onto music wire, or hardened bolts, annealing the steel by getting it cherry red hot with a common propane torch will make it softer.

Gray Beard

My Feedback: (-1)

Unless you know how to do it correctly it tends to make the wire brittle and it can snap off. I have never been able to get it back to the correct temper. I have seen others that say they can do it, I'm just not one of them. With standard tap and dies I have never had a problem cutting threads. When I saw the rodchuck it looked like the tool to use. I just couldn't come up with the cash for one. I buy my wire threaded on one end and just solder on a clevis. That I have down to a science.

jester_s1

You don't need to heat it to a cherry red. Doing so gets the steel up to critical temp which, as Gray Beard mentioned, can actually give you a brittle piece because the air can serve as a quench. If you'll use a regular lighter to heat it to a gray temper (that's one color past blue or about 900 degrees) it will be fairly soft with no chance of being rehardened as it cools.

So to the OP: is there a reason you don't want to use the pre made 2-56 push rods from the hobby shop?

LesUyeda

"I have seen others that say they can do it, I'm just not one of them. "

That is because the steel they use these days has so little carbon in it, it does not act like we expect, or want, it to. If you buy drill rod, that will work.

Les

Gray Beard

My Feedback: (-1)

Les, that may be so? I have tried to heat and bend piano wire for LG and failed at that too. In school I learned to temper in metal shop but have never been able to get it right.
As to heating metal just to cut threads I don't see the point, there is no problem so it needs no cure. I have tried to cut threads on control rods, both 4-40 and 2-56 thinking the rods would work for plastic clevises and it doesn't work that well. By just buying solder clevises and roll cut wire I'm able to get perfect rods that can be adjusted on one end.
It's just a warning to newer builders that heating there wire can create a problem. I use a small torch to solder and I'm very careful not to discolor the wire when soldering.
Z bends and soldered clevises is much easier and cheaper then trying to thread your own wire. I like to keep things easy.
Last time I heated wire to bend some LG the gear looked so good, first landing both axles broke off. So much for my skills at tempering. I read that others have the skill, I'm just not one of them. I gave up trying.

dadragon

annealing sofens tempering hardens oil quenching helps,first you need to know what is in the metal and how long to keep it in the heat before cooling so not to get it brittle and break.

kwblake

Hey dadragon. What is your background in metallurgy?

dant-RCU

My Feedback: (3)

I actually bought the RODCHUCK system when it first came out and I still use it when I need to do
a custom rod or I want to replace ARF hardware. I have both die sets but I only use 4-40 and it cuts
on 1/8 inch welding rod which is copper coated.

With all of the rods I have made for myself and others I have never had a failure or problem. I also
only use a metal clevis. I do not know if the system is still being sold - the webpage is still up but I
don't think it has been updated in quite a while.

If one really wanted to you could pick up a set of dies (3-56 and 2-56 or 5-40 and 4-40, a die holder and
some welding rod and fabricate your rods. Welding rod is cheap and is sold by the pound.

Dan

Villa

Hi Gray Beard
I have bent 5/32" diameter music wire for landing gear for over 30 years and never had a problem. I NEVER use heat. There is a secret, and I have never seen this discussed elswere. If you stick 5/32" music wire in a vice and bend it over the jaw, to make a right angle bend, it is likely that the wire will snap, and the break will be very jagget, like glass. You can severly injure your hand. I always use a heavy leather glove when bending the wire. Now to the secret, and I only ask you to try this, and offer your comment. The reason the wire may break is that the inside bend radius when bending it over a vice jaw, is WAY TOO SMALL. What I do is grind a groove at the top of one vice jaw, that the wire will bent into. The groove is just over 5/32" wide, and has a radius that the wire will bend over. This radius is equal to the diameter of the wire, which is 5/32". I hope to hear from you on this and welcome any questions.

JohnBuckner

My Feedback: (1)

I built a Bigger Smith MiniPlane back around 1970 hard to call a miniplane a big airplane at 17 feet top wing) and I choose to use home made flying wires with cut threads for the fittings.

Anyway during early testing at Chino california when the first higher (G) loads were attempted i.e. the first attempted loops on the first pull to not yet quite vertical I heard a very loud bang and the stick required a substancial hard over to the left to maintain roll. So I bailed out out of the manuver as gently as I could and fortunately I was able to maintain control with the hard over and land as gently as I could (This testing at that time was done opposite of that runways pattern and this was before the control tower was built).

What had happened was the Mininplane used two parallel lift wires in the rigging on each side to the two wing spars fore and aft. The rear lift wire at the fuselage right next to my Butt choose that high (G) moment for the threads to fail and pull out of the fitting. The riight side wing of course with only one forward lift wire washed out several inchs just like a Wright Flyers wing warping system for roll control.

This resulted in a hard roll to the right requiring almost full left stick but it held. If not I suppose I would not be here now. Anyway back to the point the very first thing is I ordered a custom set of the expensive MacWhites With Rolled Threads and the airplane lived a long prosperous life.

I never agine trusted cut theads on pushrods or any type of wire used in high tension. Just an opinion here.


John

Yup the skinny guy is me before the transformation to the gympy guy and the girl in one photo is later at 29 palms california is a niece.

TFF

Nice Smith. Not a ride I would like to take worrying if the wings stay on. I have see cheap 2-56 rods not take metal clevises.
There is a Smith at my airport in need of some help. I'm restoring a Starduster 1.