CollectingSnapOn.com

Here are three types of early 1/4 rats. Top. a 1938 GM-70-N. has no screws in the head. Middle, 1942 GM-70-L. Has the offset screws seen in the war rats. Bottom a 1945 GM-70-L. screws in the right place.
The N shows up in the 37 cat. and the L shows up in the 41 cat. So, are there any N's with screws, and are there any L's with no screws?

I think the original 9/32 drive was a sales give away. The sales people saw it and said they could sell it. The 1/4 standard did not seem to come from Snap On. Where did it come from?

Also, Plomb had 9/32, did anybody else make a 9/32?

Looking through the cats earlier I found:
1937 the M-70 N, also lists the GM-70-N
1939 the M-70 L, also lists the GM-70-N
1941 lists both the M-70-L and GM-70-L

I have found Armstrong and Williams in 9/32" drive.