I have installed the following web pages relating to North Bros."Yankee" ratchet mechanism tools:
http://jp29.org/wwnbyankee.htm .......... North Bros."Yankee" ratchet mechanism tools (overview)
http://jp29.org/wwyankeersd.htm ......... "YANKEE" spiral ratchet screw drivers (general)
http://jp29.org/wwyankee131.htm ......... "YANKEE" 131/131A quick return spiral ratchet screw drivers
http://jp29.org/wwyankee1530.htm ........ "YANKEE" 1530/1530A ratchet hand drills
http://jp29.org/wwyankee1555.htm ........ "YANKEE" 1555 ratchet breast drill
http://jp29.org/wwyankee2100.htm ........ "YANKEE" 2100/2101 Bit Brace
(Actually the links to the other pages can be found on the http://jp29.org/wwnbyankee.htm page)
I would particularly like to determine the time frame when the 1530 ratchet hand drill was suprseded by the 1530A model.
James