I have a 1932 model 9 with a lucas mo1 magneto. I need to get new bolts/studs to hold the magneto down. I assume most people just use three as the front right hand side looks extremely difficult to fit. It is currently held on with one bolt and a stud with no nut on. My question is what size is the thread and should it use bolts or studs and how long. Thanks in advance for any info.
The parts list shows two locating pegs and two studs with nuts and washers. The studs are monted diagonally but if you are able to fit three then all well and good. They are really fiddly to fit. I have been searching for my original spares and cannot find them (perhaps I put them on my last rebuild?) Any way they are 3/8 inch diameter and I would guess they have BSF threads. The nuts are fairly slim and have an over size hex (I would guess one appropriate to 7/16 bolts.
The magneto is usually tapped at 3/8 Whitworth ..... suitable length to accomodate the ally thickness of the crankcase.
Vic
My Model 10 has 3/8 BSW studs & nuts - diagonally placed as described and a real pain to get at. It looks as if it also had pegs at one time but these have been machined flush.
An advantage of Whit rather than BSF is that they're easier to engage without cross-threading and take fewer of those tiny movements to tighten them up......
Mine are 3/8" whit as well..so are the holes in my spare mags as well..When I made my bolts I made the heads of the bolts slightly longer, it's easier to get a spanner on them then..john