Geometric Die Head Markings Help

[rufushunt]

Can someone help me with what these markings are on the DS Geometric Die Head? Scanned two different manuals and can't find anything. I'm sure it's something simple.

Thanks.

 

[L Vanice]

Small-zero-large. The scale relates to the pitch diameter adjustment. Zero should be very close to nominal, but the adjustment allows quite a bit larger or smaller than nominal. I often cut .275-40 threads with 1/4-40 chasers in a 5/16 DS die head.

Larry

 

[rufushunt]

Appreciate it.