Steve W. wrote:
Volker Borchert wrote:

In the replacement steering knuckle for an IHC 453 there are two
threaded holes whose thread I can't make out: inner diameter about
10.25 mm and a pitch of 13 TPI [1].

It's a metric thread. That tractor came out of the Neuss factory in Germany.

That didn't keep them from using UNC. E.g. the bolt that clamps
the steering lever onto the steering knuckle is definitely UNC
1/2" x 13. (Whereas the steering link clamp bolts are M8x1 and
the steering knuckle top is M27x1.5.)

I think it's M12X2

My wooden rod and thread gauge think it isn't. At least not "x2".
It's definitely 13 TPI.

--

"I'm a doctor, not a mechanic." Dr Leonard McCoy
"I'm a mechanic, not a doctor." Volker Borchert