I just ordered a stainless steel nut in the correct size from McMaster Carr, ground the correct radius on the bottom to match the exhaust pipe, and welded it on.
-------- Original Message -------- Subject: Re: KR> Cyberdyne mixture meter From: Mark Langford via KRnet <krnet at list.krnet.org> I don't have one here to measure, but I'm pretty sure that Bosch sensor requires a standard 18mm x 1.5mm bung, as shown at https://www.summitracing.com/parts/sum-g2990/overview/ .