No problem, John, and thanks for your reply. I agree, it must be 1/8" BSP. I was confused by the number and learned that it is the inner not the outer diameter.
Cheers, Thomas

Hi Thomas. From your dimensions the nearest i could figure out is 1/8" BSP.
Sorry for the late answer but family problems have taken up all my time recently.
John

As previously done for my broken rocker shaft I asked again my local laser welder to try a repair. Luckily, he was successfull and I paid 20 Euro for the coffee cash. The advantage of laser welding is the low temperature input into the surrounded material. Hardened material won't loose its hardness.

Hi all! The fitting of my oil return pipe snapped. Does anybody have an idea what threat and bolt it is? I measure 9 threads on 8.7mm (about 26 TPI) and 9.6mm outer diameter.