On 18/07/2020 07:23, Chris Hogg wrote:
On Sat, 18 Jul 2020 01:22:40 +0100, John Rumm
wrote:

So there I am with a pack of M12 flange nuts and lots of threaded rod,
and I need an 18mm spanner...

Except the first set I try goes from 17mm to 19mm, so I look at my
socket set, same. Another socket set, same. The deep socket set included
with the pneumatic impact wrench, same again!

Had to use an adjustable in the end!


In comparative ignorance here, but isn't 18mm 3/8" Whit and/or 7/16"
BSF? I have sets of Whit and BSF spanners from the days of tinkering
with my MG TC.

Isn't it 11 or 12 mm that is often missing from some sets, I suspect
there is a preferred set of sizes in a standard somewhere.

Also quite a lot of Allen key sets are missing 7mm, which is common on
brake calipers.