6-32 screw

[kak8]

Hello

I had to build a thicker Bubble Danncer horizontal tail, and the 6-32 nylon bolt that goes into the V mount is to short now.

I`v been trying to find a deler in europe, but even in Great Britain it seams imposible to find an inch bolt.

Can you help me to find a deler anywhere in the world?

My Bubble Dancer is grounded until i find some 6-32 nylon bolts.

Can someone explain what 6 is and what 32 is?
I`ve heard that 6/32 and 6-32 is not the same.

Thanks

Adam

[Bryan Quick]

Adam-
The american screw thread system is screwy. No pun intended.

If you go to http://www1.mscdirect.com/cgi/nnsrhm and so a search on 6-32 machine screw, you can find what you need.

Page 1958 on the MSC catalog has nylon machine screws in various sizes.

Page 1957 has socket head nylon cap screws.

HTH-

Bryan

ps 6 is the size and 32 is the thread pitch expressed in threads per inch (TPI)

[John Walter]

PM your mailing address and I'll track down a couple here in the US and mail them to you.

[tonyestep]

Another way is to re-tap the hole for a metric screw. Googling on 6-32 screw diameter reveals that the minor diameter of a #6 screw is .098". Googling on metric screw diameter produces a table showing that the minor diameter of an M3 screw is .0995. You might be able to run an M3 tap through the hole and use an M3 screw. Or perhaps it would be a good idea to use a larger size, so that you're cutting threads into fresh material; in that case, an M3.5 minor diameter is 0.116, so that should work out fine.

[IwantaJet]

A 6-32 screw fits in M3 threads with just a little bit of play. I think tapping with an M3 tap would work great.

I would trade you some 6-32s for some M3s.

[Bryan Quick]

Another solution, re-do the platform to accept the M3 using epoxy and flocking.

- Drill the platform out to a diameter larger than the M3 screw you would like to use
- Wax a M3 _steel_ cap screw to form the threads
- Mix flocking/cabosil and fill the hole, ujse the M3
- When it sets, unscrew the steel screw and you're good to go

[Andy W]

Re-tapping for metric (if that's all that you can find locally) is the answer. I've done the same thing here, the other way (re-tapping metric threads to SAE, as metric nylon bolts are hard to come by here)..
..a

[lincoln]

32 is 1/pitch, i.e. there are 32 threads per inch. As far as I know, #6 is arbitrary, but it's 0.138" major diameter.

If McMaster Carr does business in Europe, you might try them. (mcmaster.com). They have everything, tho they're not as strong in metric as they might be. Here in the USA, they're very quick.

The pitch on M3 threads, as I recall about 0.45 or 0.5mm, is pretty different from that on the 6-32, which works out to about 0.8mm. Suggest, if you're in a hurry, you try a metal M2.5 through bolt with a nylon insert locknut.

Making epoxy threads seems like a good way out if you do it carefully. Might want to make sure that part of the epoxy extends out over the bottom of the platform so it doesn't pull through.

Depending on the details, you might just do a counterbore for the 6-32 screw.

Also, if you know anyone who goes to the USA often, 6-32 screws are sold in almost any hardware store, or they could order you a lifetime supply from McMaster Carr for not very much, and bring them back. (Although I suspect after 10 or 20 years, nylon screws may be brittle.)

[kak8]

Thank you very much for all the ideas.

Re-tapping was one of my last choices - there is really not much material around the thread. Maybe one or 2 thin carbon fabric layers.

Now I need some time to figure out what to do.

Thanks again

Adam

[lincoln]

Yes, but the major diameter of the M3 is SMALLER than that of the 6-32, so it shouldn't compromise the fabric.

[kak8]

I ended with making a new M4 thread in the existing thread. The fabric was thick enough so I didn`t need to use epoxy. The new thread was strong but I used a few drops of thin CA to build it up and re-tapping a few times. Maybe I will reinforce it from the outside with some thin fabric.

Thanks again for all your help.

Adam