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Building Tips and technical articles. => Building techniques => Topic started by: Dennis Toth on November 04, 2014, 06:32:37 AM
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Guys,
I'm looking to make some joiners to connect flaps around booms. At first I thought I would use regular music wire rod but I remembered a technic a flying bud used years back using drill rod. The drill rod is stiffer in torsion. Looking on line at Grainger's site there are several types of drill rod i.e. - Oil harden, Air hardened, Water hardened. Not being a metallurgist I don't understand what each type is used for.
I think what is needed is one that would allow the 90 deg bends needed to make the joiners without cracking. I was thinking that one might need to heat up the bend point then re-harden. Seems the water harden would be easiest for our application in the home shop.
Anyone use this material for horns or joiners?
Best, DennisT
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Good Morning Dennis;
Drill rod was talked about recently in the thread titled "Control Horns". See: http://stunthanger.com/smf/index.php/topic,37083.0.html
r/
Dave
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Here is what Allan Perret said over in that thread.
"1-Use A2 drill rod [8888K181] from McMaster Carr for tweakable horn wire"
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Dennis,
Congratulations on that 3rd place!!
Tom Morris sells hard wood flap ends drilled for a snug .125".
If you use those you can adjust the flaps if necessary without damage and use .125" HS wire.
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Here is what Allan Perret said over in that thread.
"1-Use A2 drill rod [8888K181] from McMaster Carr for tweakable horn wire"
Here is the original source for the A2 recommendation. Derek Moran made control horns as works of art.
http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=331672&mesg_id=331672&listing_type=search .
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Allan,
Thanks for the great link. Derek's work is impressive. It would be great if Jim Lee would make up some tooling to build these. I am going to get some of the A2 drill rod, Grainger is close by and has this type of drill rod. I ordered a mini mighty wire bender to be able to make up the horns and joiners. Is there a source for the flat steel already cut to 3/16" by 1/16"?
Best, DennisT
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Aren't there aluminum rod and aluminum flat stock materials available? I believe so. Can be tempered after bending and welding.
All that work using steel?
Aluminum? Correct me if I'm wrong, but the same amount of work with not nearly the same amount of weight?
JMHOWNTN
Just My Humble Opinion Worth Next To Nothing. n~
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Allan,
Thanks for the great link. Derek's work is impressive. It would be great if Jim Lee would make up some tooling to build these. I am going to get some of the A2 drill rod, Grainger is close by and has this type of drill rod. I ordered a mini mighty wire bender to be able to make up the horns and joiners. Is there a source for the flat steel already cut to 3/16" by 1/16"?
Best, DennisT
McMaster also has strip steel in that size and many others, 3ft lengths.
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Guys,
I'm looking to make some joiners to connect flaps around booms. At first I thought I would use regular music wire rod but I remembered a technic a flying bud used years back using drill rod. The drill rod is stiffer in torsion. Looking on line at Grainger's site there are several types of drill rod i.e. - Oil harden, Air hardened, Water hardened. Not being a metallurgist I don't understand what each type is used for.
I think what is needed is one that would allow the 90 deg bends needed to make the joiners without cracking. I was thinking that one might need to heat up the bend point then re-harden. Seems the water harden would be easiest for our application in the home shop.
Anyone use this material for horns or joiners?
Best, DennisT
A2 Air-hardening tool steel. I got it from McMaster-Carr. Derek put me on to it and it works very well. I did some test parts and tested them to destruction. Its not as stiff or springy as music wire, but after brazing and heat-treating it was a bit stiffer and almost could not be broken from fatigue. You can bend it through a huge angle, bend it back, with no obvious damage. Very much tougher than music wire and was not brittle near the braze or near the heat-treated section. The music wire, treated as I usually do it, broke pretty quickly in comparison. I was much happier with the results, and am not going to worry about breaking down the road like with music wire.
Brett
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Brett,
Does it harden only near the brazing or did you heat-treat the whole wire?
And does it harden by itself as it air-cools after the heating?
Lauri
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Brett,
Does it harden only near the brazing or did you heat-treat the whole wire?
And does it harden by itself as it air-cools after the heating?
Lauri
If the steel is not heated to "critical" about 1650F, or cherry red, it will not harden at all and will remain "annealed".
The bending will do some work hardening, which may account for the part being more stiff.
Phil
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Brett,
Does it harden only near the brazing or did you heat-treat the whole wire?
And does it harden by itself as it air-cools after the heating?
Lauri
It doesn't harden very much around the braze, or at least it doesn't leave the diamond-hard sort of areas like music wire. I did relieve it a bit by putting it in the oven at 500 degrees for a few hours and then letting it cool slowly. That stiffened is substantially. I saw no consequential work-hardening at the bends, which is another thing that always bothered me with music wire. My test parts had all these things and was treated the same way, and it proved to be very tough, far tougher than I expected.
Brett