Lucas SR2 - locking screw for the impulse body

Hello,
On a Lucas SR2 Magneto, there is "locking screw" for the impulse body. I believe it is LH thread, but that is where my knowledge stops!

I have searched for a while and cannot fins any information. Does anybody know what size, length and thread this screw is please?

If you have a source, that would be wonderful!

Cheers

Peter

Had a look through parts list and workshop manual but, sadly, neither give the actual size only a part number. Can you measure diameter?

Thanks for trying.

I can see if I can measure the diameter, but the thread is very recessed, so I will have no chance of getting anything to measure threads in there.

Peter

Woodsman wrote:Had a look through parts list and workshop manual but, sadly, neither give the actual size only a part number. Can you measure diameter?

What was the part number please?

Cheers

Peter

I can send you a copy of docs. PM me with email address.

puffernutter wrote:Thanks for trying.

I can see if I can measure the diameter, but the thread is very recessed, so I will have no chance of getting anything to measure threads in there.

Peter

Try a series of drill shanks in the hole, that will give you a close size for the core size of the thread and then check it against various threads sheets.

Maryalice

maryalice wrote:

puffernutter wrote:Thanks for trying.

I can see if I can measure the diameter, but the thread is very recessed, so I will have no chance of getting anything to measure threads in there.

Peter

Try a series of drill shanks in the hole, that will give you a close size for the core size of the thread and then check it against various threads sheets.

Maryalice

Funnily enough late last night I removed the impulse body and had slightly better access. I did exactly as you suggested and (at around 4.7mm) I suspect it could be a 1/4BSW LH thread. There are others close e.g. BSF, but I am not familiar with the history of threads or Lucas to know if they are more likely to use BSW or BSF.

Peter