Quote Originally Posted by Philip Davies View Post
Twice in the last month I have sorted through a pile of Allen keys, to try to distinguish between metric and imperial sizes. My digital vernier has not helped greatly. I would like to have a quicker method!
What's a "digital vernier" ? Did you mean a digital caliper ?

Don't keep them in a pile. Sort them carefully once and store them in separate wooden blocks with the sizes marked.

Most of my Allen wrenches, even the cheap ones that came with flat pack furniture, have the sizes marked on them. Have you inspected yours closely to see if they have markings ?