hi,

I brought a set of Sabelt harnesses ( 4 point ) which were fairly new and unused.

I need to find the correct nylock nuts for the bolts.

I know they could be one of either metric or imperial

Can anyone tell me what they should be. i thought they were 7/16th UNF ( because the tops were ) but the nuts i brought would not screw on....

7/16 UNF is correct.

Not necessarily. Some Sabelts are 8mm....
But then thats much smaller than 7/16UNF- the nut would completely slip over them!!

have you got powder coat in the threds ?

nope.

its the bottom bolts.

the top ones were 7/16 , as i cleaned them out with a tap.

I then brought some 7/16 nyloc bolts for the bottoms, assuming they would be the same thread, but seems like either

1) they are not the same

or

2) the nuts i brought were not actually 7/16 even though i ordered 7/17 nuts...