HELP ! Thread ID required
 

Folks I am busy making a copy of the steering location pin which sits at the base of the steering column, it's the one that screws through the cast yoke on the base of the column then through the linkages located at the base... A nut then winds onto the bottom of the bolt to hold the linkages in place.. I need to know what thread the coarse thread is that winds into the cast work ? I thought 7/8 UNC / BSP but when I tested the die I have on the pattern bolt I have,although close, it was not right....... Any ideas ???

Could be BSW, with a large thread such as this, lay an Imperial rule along the thread and count how many threads per inch. .... unless you have a set of thread guages of course.

I seem to think both BSW and UNC are both 9tpi for 7/8", but different thread angles so your die might look similar, unless it is 7/8" BSF which I think is 11tpi. I am aware of BS threads being used on Canadian carriers as they were producing them to the British War Office spec.