Lambda probe

[Fred]

Was measuring the Lambda thread Yesterday having removed it from my G cat
and think i`m correct as Pitch of 1.5 but my Digi verniers gave a reading of 17.86
or very near.

Couldn`t find any thread to match in my Zeuss book.

Anyone know exactly what thread it is?

Fred.

[Yoof]

M18x1.5 mate 

[Fred]

Thanks Yoof,
I thought so as if we cut a M10 thread it would measure slightly
less on the bolt so rounding it off to the nearest.

Fred.