Went through postings, tech section, didn’t find it.

On eight inches headlamps, what sizes are the two bolts holding it to the girders?

In this instance, a Norton big4.

Thank you members.

Well, M20 are 5/16 BSC (26tpi) x 19/32, and 5/16 BSC x 21/32, 2 off each
Baz

email (option): binnawan@iinet.net.au

I think Henri means the two bolts in the side of the lamp. These are 5/16 BSC and are usually plated brass with a deepish domed head. Ron

email (option): ronpier@talk21.com

They are indeed plated brass and with a thick washer under. Initially dull-chrome but presumably cadmium plated later.

They're not listed in the Norton Spare Parts lists as they are Lucas components. LU/112561 (screw) and LU/137141 (washer).

Would brass have been used to facilite earthing of the shell or is it simply that it nips-up with less spanner pressure ?

Merci,

Tout est bien!