Maybe someone can tell me if this is already being done by someone, or
if there's a technical reason why this is not a good idea.
I've found when using helical wire type thread inserts in shallow,
blind holes that the taps provided with the kits are simply not
adequate. They are taper style taps, where you really need a plug tap
or even a bottoming tap for a blind hole. So what I end up doing is if
I'm repairing one piece, I drill and tap all the holes and then cut the
end of the provided tap off with an abrasive wheel, give the end a
slight chamfer on the bench grinder, and then go back and bottom-tap
the holes, insert my inserts, etc.
The only downside to this procedure is that then the remainder of the
kit is useless until I buy another one to get a fresh tap, as it's hard
to get a plug tap, especially a homemade one, started in a fresh
drilled hole by hand.
The question is, why not provide the kits with TWO taps, a taper tap
and a bottom tap? Does anyone even make ready made bottom taps for
helical wire thread inserts, and can you buy the regular taper ones
separately? Or is there some technical reason that what I'm doing,
while it seems to work, may be incorrect?
nate
Scirocco - 20 Jan 2007 21:40 GMT
> The question is, why not provide the kits with TWO taps, a taper tap
> and a bottom tap? Does anyone even make ready made bottom taps for
> helical wire thread inserts, and can you buy the regular taper ones
> separately? Or is there some technical reason that what I'm doing,
> while it seems to work, may be incorrect?
While I don't know whether or not what you're doing is OK, you can buy
bottoming heli-coil taps at www.mscdirect.com as well as other sites.
Chris
David Geesaman - 20 Jan 2007 21:48 GMT
> The only downside to this procedure is that then the remainder of the
> kit is useless until I buy another one to get a fresh tap, as it's hard
[quoted text clipped - 8 lines]
>
> nate
When I worked for an aerospace company, our machinists would do this if
you needed a really shallow tapped hole. We worked with helicoils
regularly, and so buying another helicoil tap was not a big deal, and
from then on you had both.
Dave