Harness Captive Nut Thread
 

Can anyone confirm whether the 7/16 captive nut on CP18 is UNC or UNF I suspect UNF but would like some clarification before I weld them on

You are correct in thinking that its UNF.

Why do the harness mounts have the imperial thread? What goes in them?
The thing is imperial taps and nuts are nigh on impossible to obtain here, can the harness mount be modified to use metric?

7/16 Unf is approx 11mm.Unf has been used for ages and is a fine thread.So you can got to 10mm or 12mm metric Fine.Personally i would go to 12mm but check that these will fit through the holes in the harness or seat belt.

It's also because, if you take a look at all the harnesses and harness mounts, the supplied bolts are 7/16 UNF.

Nothing to stop you using metric, but would definitely go for M12, as has been said, make sure it will fit your harness mounts

Ebay
 

If it is of any use to you. 7/16" UNF nuts,bolts, taps & dies are readilly available on ebay ;)

WE have a similar problem in the UK with the metric fine stuff. Hard to find & expensive when you do. :(

No real reason as to why you can't use M12 metric fine instead though. :)

I think I paid £7.99 for a set of 3 7/16UNF dies (taper, second, bottom)

Obviously not the worlds highest quality taps, but for the 4 holes I needed to tap, they were fine.

Same goes for the nuts, I got them off EGay, t'was about £1.99 for 10, in Grade 8.8