Curt:
You are correct. Although they have the same TPI they do not have the same
pitch. You can get away with switching them in steel but aluminum gets
unforgiving very quickly. Up though the late 60's Bosch spark plugs had the
standard number of threads but a different pitch. We ruined the spark plug
holes on an aluminum head switching between Bosch and American spark plugs.
Bob and Annice
1960 Sprite (Mk IV in disguise)
1966 Mk III Sprite (still in boxes)
message dated 8/8/01 5:42:31 PM, CNAArndt writes:
<< I know that I will hear from some of you saying that no, it's a ANC or UNC
(there is a slight but insignificant difference in these two) bolt and you
are right that it will fit since both the Whitworth bolt and the ANC/UNC
bolts will have 18 TPI, but it is not correct. >>
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