I don't know! They were done for me by Mel at Tandems East who called the process by the word "helicoil" as far as I remember but I have no clue. Whatever he did and they are, they work just fine.
-S-
David Benson wrote:
>
> Steve,
> Are your cranks really helicoiled, or are they "inserted".
> Helicoils "are precision formed screw thread coils of stainless steel wire having
> a diamond shaped cross section" see: http://www.emhart.com/
> An insert is a steel tube with a male and female thread, which is threaded into
> the crankarm to replace the original thread, either because it is damaged, or
> wrongly oriented for the application, as in a tandem crankset. Inserts used to be
> a common fix for stripped crank threads. A special tap/reamer was used to open out
> the pedal hole to accomodate the insert.
>
> DB
>
> Steve Freides wrote:
>
> > People have simply retapped, with reverse threading, and gotten useable
> > results. Obviously inferior in terms of the strength of the threads but
> > it has been done.
> >
> > "Helicoil" is a brand new for a threaded insert - the pedal hole is
> > drilled out, the insert with reverse threaded installed, and off you
> > go. That's what I ride.
> >
> > -S-