How to identify an internal thread

[Robotstar5]

Have you tried looking at stationary engine forums? I understand these magnetos were often used on them.

I asked my brother for you. He got into engineering as an auto electrician. He advised trying the stationary engine people.

It was a stationary engine forum that identified it, thanks for asking your brother

 

[Carl Wilson]

No problem.

 

[Rig Pig]

Try http://www.davelindsley.co.uk/magnetos.html

 

[Robotstar5]

Try http://www.davelindsley.co.uk/magnetos.html

Thanks for the link, unfortunately they don't cover the model I have

 

[Robotstar5]

Having bought and fitted my nice SS dome head screws I realised I won't be able to undo them to service the CB points once I've re-fitted the flywheel housing while watching a video I saw they originally had bolts with extended hexheads which would allow me to undo them with a spanner from the side.

Do these type of bolts have a name or would they be specially made for Wipac/Wiko etc.?

I may be contacting @doubleboost with a suggestion for a SNNC