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 .
WTF is this? It's obviously neither M12(x1,75) nor UNC1/2x13...
Is there an UNC15/32x13? Or even a cross-over 12mmx13TPI?
Any hints appreciated .
 I screwed in a 11mm square wood rod to get that accurately.
 Yes, I'll contact the vendor. But, I prefer not to appear totally
ignorant on the phone ;-)
6 years ago