Re: [ATM] Threaded inserts for 1/2" carbon fiber tube?

[Curt Diggs <mokiman_210@yahoo.com>]

Case-hardened steel inserts will not be tappable. They're designed to stand having a high speed hardened drill bit pass through without damage so they are very hard, probably as hard as the tap!
   
  A tight or at least snug mechanical fit of the bushing into the CF tube will insure the strongest possible joint when using JB Weld. Leaving a gap will actually make it weaker.
   
  JB Weld is a filled epoxy designed to be used specifically with metals. I've even used it to glue parts of aluminum mufflers together for small engines and it held quite well. It's not expensive and can be found at most hardware stores. Be sure to use the slower curing version, not the fast stuff.
   
  If you're concerned that JB Weld won't be strong enough then I suggest visiting a kite shop (lots of 'em on line) and look for the special type of cyanoacrylate glue used for kite CF frames. It has a filler/reinforcer in it and creates fast, incredibly strong joints. It's fairly expensive but a little goes a long way. It takes some practice to get it right because it bonds very quickly when used so you may want to practice with some scrap first.
   
  Curt
   
  >Message: 9
>Date: Tue, 18 Mar 2008 20:40:06 -0400
>From: "Chris Todd" <christopher.todd@gmail.com>  Subject: Re: [ATM] >Threaded inserts for 1/2" carbon fiber tube?  To: atm@atmlist.net
>Message-ID:
 ><8cb754430803181740u134a4821x6073516504e437c3@mail.gmail.com>
>Content-Type: text/plain; charset=ISO-8859-1
>
>Curt,
>
>That looks like a pretty good solution, I'll have to consider that.
>They're made of case-hardened steel - would it be possible to simply
>tap them for 1/4-20 threads?
>
>I also found threaded inserts called "weld nuts" at McMaster-Carr
>(e.g., part # 90860A115), but the shaft OD was 3/8".
>
>If the OD of the steel bushings are exactly the same as the ID of the
>CF tubes, will there be any room for epoxy?  Should I get steel
>bushings that are, say, 3/8" OD instead, leaving 1/64" between the
>bushing and the ID of the tube, to give some room for the epoxy?  And
>may I assume JB Weld is nominally the same as any two part epoxy resin
>(I have some West system epoxy I got to experiment with fiberglass
>cloth and styrofoam)?
>
>Thanks again to everyone for suggestions and hints, I appreciate it.
>
>Chris



       
---------------------------------
Looking for last minute shopping deals?  Find them fast with Yahoo! Search.
_______________________________________________
ATM mailing list http://www.atmlist.net/