Instructables user cbm104 attributes this cool trick to a leather-working book published in the ’60s, the title of which he does not remember. If anybody knows the reference, I’m sure he’d be glad for a heads-up. Or just leave a comment here and I’ll pass it along.
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Email me at “code71b@yahoo.com” and I’ll give you an e-book that I have dated 1935 on this subject. It’s very good, and free to give away, as the date is out off copyright. Hope it helps. Bill