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Author Topic: Best method of heating and forming a needle of a nva to reshape it?  (Read 711 times)

Offline frank mccune

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Best method of heating and forming a needle of a nva to reshape it?
« on: June 28, 2014, 06:12:41 PM »
    Hi:

      Any suggestions?

                                                                                                                  Tia,

                                                                                                                   Frank

         
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Offline kenneth cook

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Re: Best method of heating and forming a needle of a nva to reshape it?
« Reply #1 on: June 28, 2014, 06:24:01 PM »
         Frank, I'm perplexed by this question. What are you trying to do here? In your next post your asking how to protect the needle. Is this what your trying to accomplish? What needle are you trying to bend? Are you suggesting this needle to be a Fox unit? Just clip the knob off of the top with a pair of side cutters. Get two pairs of pliers and have at it. Bending this needle won't break it. The reason it breaks is due to how deep the threads are cut within it. If you bend it into a L shape above the ratchet knob you can shorten it enough so that it doesn't extend above the top of the fuse. Ken
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Offline Steve Helmick

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Re: Best method of heating and forming a needle of a nva to reshape it?
« Reply #2 on: June 28, 2014, 06:35:25 PM »
You're referring to ST, ST Clone, Brodak, or Randy Aero NV? I can't say I've purposely bent any of those except Randy Aero's, which appear to be stainless steel, come straight, and don't need heating...tho you certainly wouldn't hurt anything to wave a propane torch across the bend area a bit. I use round-nosed pliers for that.

I also tried Daniel Dirt's trick with the R/C car pinion gear (they're aluminum and don't weigh much of anything) for a knob. The interesting thing is that a NV with a knob is much less likely to turn to adjust itself. But if you do it, cut the NV off as short as you can, because the added mass can also make them snap off on high vibrating engines like...well, about any of them. The pinion gears are pretty expensive, IMO, and when the NV breaks, they're pretty much gone forever at most flying sites.  H^^ Steve
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Offline Tim Wescott

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Re: Best method of heating and forming a needle of a nva to reshape it?
« Reply #3 on: June 28, 2014, 06:53:49 PM »
Frank, are you straightening a bent one or putting a bend into a straight one?

In either case I think I'd just cold form it.  In the case of straightening a bent one, use pliers on the unthreaded part, and a block of wood on the threaded part.  Sometimes, once you've gotten it mostly straight you can take out more of the remaining bend by laying the thing on a block of wood with the bend up, placing a blunt punch of some sort on the top of the bend, and tapping the punch with a hammer.  It takes some experience to get a feel for it.

If you are trying to straighten a bent one, just do your best and then go buy some replacements (or a remote NV!).  You'll never get a bent one as straight as new.
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Offline Phil Krankowski

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Re: Best method of heating and forming a needle of a nva to reshape it?
« Reply #4 on: June 28, 2014, 08:31:07 PM »
If you are straightening the tapered portion of a needle rolling it between two pieces of smooth steel bar works about the best.

Rolling messes up the threads on the threaded portion, anyways if the portion that threads in is bent, when straightened the thread pitch will be stretched out some.  If it is the last turn or so as it enters the engine then it will make finding "closed" funny.  If the bend is threaded all the way in the needle is junk.

My experience is based on many crashed Cox bee engines.

Phil
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