No, haven't read that, as yet, but do know that the square bolt was not used by very many as it is very difficult to do and takes a lot of skillful handwork. Lindner used it exclusively so it must have been the better way to go, if quality were the idea.
The square bolt could not be machined as the round one could. Large volume makers needed to keep the round bolt for the round hole.:}
Best,
John

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