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View Full Version : Can some one lend me a 7/8 heli-coil kit?


Mark Newhan
June 29th, 2009, 22:17
Does anybody have that kit. I have to helicoil two holes in a billet upper control arm. McMaster Carr sold me a defective tap and the threads are oversize. I attempted to discuss it with them and in short got the heave ho. I was VERY pissed to say the least. It is very uncustomary of the type of service that I have gotten in the past... must be a sign of the times.

Thanks in advance to anyone that may be able to help.

Mark
mikeyfrombc
June 29th, 2009, 22:20
a good tool and cutter grinding shop should be able to regrind that tap for you
Mark Newhan
June 29th, 2009, 22:34
It was .005 oversized. The tap got used on the two holes on the passenger side billet aluminum arm. .005 is not that much oversized except when it comes to threads. The rod end is sloppy in the holes.

I have several plug taps but did not want to have to grind the "plug" portion off in order thread the holes in order for the rod ends to screw all the way in. The tap I bought was a bottoming tap. I ended up grinding down one of my plug taps in order to finish the other arm.
partybarge_pilot
June 30th, 2009, 10:08
Oooo, somebody sent you a plating tap........

Tap the other one with the oversize tap and have the arms chromed.......:D
randy68
June 30th, 2009, 10:16
Oooo, somebody sent you a plating tap........

Tap the other one with the oversize tap and have the arms chromed.......:D

Ha! good thinkin!:eek:

(Sorry, biggest I have is 5/8")
FABRICATOR
June 30th, 2009, 18:28
In critical places, I use thread forming taps in aluminum and other soft metals. They literally forge a thread instead of cutting it. If you don't see heli-coils in that aluminum block, there's a good chance all the threads were made using these. You will need some kind of positive alignment to get things started, no hand jobs here. A half inch is very hard to turn, I would'nt even try motivating a 7/8" by hand. It also works better to use a reamer to size the holes rather than just drilling them. Again no freehand. If you break one of these off, they are not like fluted taps. It can take the EDM guy many hours to remove it. It's just an option...


http://westportcorp.com/taps/taps/ForTapLOR_1.jpg
These are westport.com but there are others.
mikeyfrombc
June 30th, 2009, 19:23
In critical places, I use thread forming taps in aluminum and other soft metals. They literally forge a thread instead of cutting it. If you don't see heli-coils in that aluminum block, there's a good chance all the threads were made using these. You will need some kind of positive alignment to get things started, no hand jobs here. A half inch is very hard to turn, I would'nt even try motivating a 7/8" by hand. It also works better to use a reamer to size the holes rather than just drilling them. Again no freehand. If you break one of these off, they are not like fluted taps. It can take the EDM guy many hours to remove it. It's just an option...


http://westportcorp.com/taps/taps/ForTapLOR_1.jpg
These are westport.com but there are others.

i,ve used a small one # series on copper they work very well