Ever wondered why you canÂ’t find a spanner to fit the nuts on battery terminals?
You know the ones that look like 13mm or ½” but that no spanner seems to fit properly!
Well, that’s because they are ¼” Whitworth!
ThatÂ’s right, decades after all other sections of the motor industry had gone metric, battery terminal clamps still used 19th century Whitworth fasteners.