Heilcoils and other thread inserts don't go to the next standard thread size
to the best of my knowledge.
A helicoil kit comes with some bizarre sized tap that is set to the outside
of the helicoil. For example if you have a stripped 1/4X20 hole, it does
not tap out to 5/16X18 or 5/16X24 because the threads per inch have to
remain constant between the desired size and what it is being tapped out to
for the helicoil. So if you are installing a helicoil in a 1/4X20 hole
whatever the size the tap is it will be 20 TPI.
So if your knob is larger than the shift lever, you can have a custom insert
machined assuming the difference is large enough, or you might be able to
fill the hole with some type of filler that can then be drilled and machined
(JB Weld?) or you can buy a new knob.
On Wed, Mar 31, 2010 at 2:13 PM, Max Heim <email@example.com> wrote:
> Are you thinking of Helicoils?
> It will probably require drilling and retapping the knob, to the next
> SAE thread.
> Max Heim
> '66 MGB GHN3L76149
> If you're near Mountain View, CA,
> it's the primer red one with chrome wires
> on 3/31/10 1:00 PM, Barrie Robinson at firstname.lastname@example.org wrote:
> > I got a beautiful gear shift knob from Larry Heaps who can be found
> > on www.britcot.com - it was for my under restoration Aston. But, as
> > usual, Brit threads are different and it will not fit. The gear
> > shift thread is 5/16 with 22 pitch, the knob is slightly larger than
> > 5/16 with bigger thread. There are some inserts one can get but I am
> > damned if I can remember the name and what they do. Can someone help
> > here please? - Thanks in advance for responses.
> > I tried plumbers tape and that was hopeless.
> > Regards
> > Barrie
> > email@example.com
> > (705) 721-9060
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