...With the changes from BSC to SAE around '68 I did not know if the cam thread changed. Just giving 1/2" BSC does not give the thread pitch.
Phil, could it be your pattern 24-7000 was UNF, not BSC? UNF has truncated peaks, not rounded which may have interfered with the BSC cam thread.
the parts-# for the nut for A65s has been the same from 1964 'til the bitter end, so I suppose they never changed the thread for the cam shaft nut.
I am even inclined to think the differing parts-# for 1962 (sorry no 1963 sparts list available here) is more like linked to the nut form or surface treatment than to a differing thread.
The spare parts list states the thread to be 1/2 BSCyc, whilst the conversion tables attached to the workshop Manual
list the 1/2" BSCyc thread to be either 26 or 20 tpi.
Prior to re-cutting I had tried the nut on two used camshafts and one brandnew SRM cam but couldn't get the nut to catch.
After having re-cut the nut's thread with a 1/2" UNF
tap the nut could be screwed on all of the camshafts I have easily.
As stated previously, 1/2" UNF
has the same thread angle and pitch as the BSCyc thread in question, so I opted for the bodge to ignore the rounded peaks in order to get the cam pinion on.
Surely, this is not how the makers intended but fair enough for me.