Hi everyone,

Iíve recently come across a very old Yale lockset which looks alot like a Sargent 8 line tubular. I believe it is a GY series lock (does this even exist?)

I donít think itís a D-1 tubular (which I have the parts diagrams for), and it definitely is not anything newer in the 5200,5300,5400 series. The two halves of the lock body are held together by a large metal ring that circles the entire thing. It is fastened to the door with large nuts that screw down on the knob collars under the decorative roses. The inside knob even has double retainers (2 poke holes opposite each other). The cylinder has the old style YALE logo with the border stamped on the plug just like many of the old mono locks did.

Any idea what model it is, how old it might be, or how to take it apart? Any info is greatly appreciated.