Tachometer / Clock screws

[Steve S]

Anyone know off hand what size the threads are to hold the clock to the tach? I don't seem to have any screws in my spares to fit. - Steve S - TC8975, LA, CA

[Bob Grunau]

Steve, Been away but didn't see an answer to your question. The clock screws are 4 mm x 0.75 mm thread. Bob Grunau Anyone know off hand what size the threads are to hold the clock to the tach? I don't seem to have any screws in my spares to fit. - Steve S - TC8975, LA, CA

[Roger Furneaux]

hi Steve - I've been "AWOL" for some three weeks (we are five miles from the exchange, and the fone line has got an aweful lot of cables strung on poles with tree branches waving around...): don't know if anybody replied, so will tack on a reply I made last August: hi Eric - Bob is right, these screws are M4 x 0.75, with a domed cheese head (is that called a filister?). The screws measure 0.154"/3.91mm diam. and are definitely NOT 3BA. I would have put money on them being the same as the tank sender, which I think we decided are 5/32" BSW x 32 tpi, so I initially tried some Meccano screws, but 0.75mm pitch is 33.9 tpi. Strangely, modern metric are M4 x 0.8, which does not figure in my tables, in the Tracey catalogue, or on my thread gauge!!! Eric Worpe wrote:

>Many thanks to Bob, Craig and Ian for their replies. >M4 x 0.75 is almost identical to 3BA as the table below shows:- > >Thread form:- M4 x 0.75 3BA No.8 ANC No.8 ANF > >Diameter:- 0.157" 0.161" 0.164" 0.164" >T.P.I:- 34 34.8 32 36 > >One is almost spoilt for choice, this reminds me of the debate >about the screw threads for the sender unit on the petrol or gas >tank.

Steve Simmons asked:

>Anyone know off hand what size the threads are to hold the clock to >the tach? I don't seem to have any screws in my spares to fit.