Yale No. 26 Catalog

[Tom Gordon]

so does anyone have a bicentric??

[Dean Nickel]

I have a mortice cylinder.

[Tom Gordon]

6 pin even back then! I was wondering how the meachanism worked on the rim cylinder...

[BBE]

6 pin even back then! I was wondering how the meachanism worked on the rim cylinder...

It is hard to date when Yale went to a 6 pin cylinder but I am certain it was before 1896. That was the year they were issued the patent for the G Series multiplex keyways. The first key system for that multiplex was actually an engineering drawing with the bittings on it.

The Yale MACS at the time was 4 because of the 100 degree included angle used in their bittings. Having 10 depths of cut didn't help much with that kind of MACS.
BBE.

[Dean Nickel]

BBE, You NEED to write a book on lock history. I would LOVE to read it!