Shopsmith Forums

I wish I had the B headstock. Mine's definitely an "A" based on viewtopic.php?t=8938this thread

A 1954 Greenie would have an "A" Headstock. They changed to the "B" Headstock in October 1955. The Speed Changing Mechanism exploded part diagram you have in your original post is for a "B" or "C" headstock and the diagram at the end of the Inspection and Cleaning PDF Ed linked to is a "B" Headstock. I am not sure which "spring" in the "A" Headstock Speed Control Assembly you are referring to. In the diagram below the two springs are indicated by red arrows. The one near the top of the picture is the Stop Spring part number B3046. It is held in place by the On/Off Switch and must be pushed to go into higher speeds as previously described. The Stop Spring is specific only to the "A" Headstocks and was one of the changes made when the "B" Headstock came out. Another change was adding the rear inspection hole under the Logo Plate. For the "B" Headstock the Stop Spring was replaced by the one marked Spring (current part number 504196) in your original post and is still used in the "C" Headstocks. The one lower near the right side of the picture below is the Dial Spring part number A3040. The Dial Spring (current part number 504228) is still used in the Speed Dial Assembly for conventional Headstocks.

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JPG's thread A Headstock vs B Headstock you linked to above is an excellent comparison of the two Headstocks. Although not specific to this thread there were changes to the "A" Headstock prior to going to the "B" Headstock just as there were changes to the "B" Headstock before going to the "C" Headstock. This includes changes to the main Headstock Castings themselves.

The spring I'm referring to is the spring labeled "A 3040" below.

That should be the same as current version.