I tried several thread chasers, 12mm = too big, 10mm = too small,
7/16 - 20 = perfect. Surprises me, but then I am surprised more often
lately.
Maybe a North American seat belt standardization thing?

Regards, Vern

> Rear pillar being the one midway above storage hatches in Westy. I
> assume it's a bolt hole for shoulder belt on seat belt.
>
> Only have an SAE thread checker thing. Metric one is hiding somewhere.
>
> Thanks!
>
> Neil.
>