Info Gather: 8W Collets?

[Red96]

A buddy of mine purchased a bunch of collets that he thought were 5C.. After some cleaning he realized the thread pitch on the ends of the collets didn't match that of 5C. I guess he determined them to be Wade 8W collets from the info he found in the Machinery Handbook.

Any information you could share regarding this type of collet would be greatly appreciated.