The King Cockeyed Hammer (and the later copy from Micro) started life as a regular factory hammer. Given the desire for the "cockeyed" feature (offset spur--to the left, right, or both), one simply sent the hammer off (along with $5 in the case of King) to the vendor, where the factory hammer had its spur ground off and the "Cockeyed" replacement welded in place, with the case hardening redone. The resultant product (from King) varied in workmanship from absolutely flawless to bush league. One could send the whole gun, where King would tend to the disassembly/reassembly at an additional charge. Given the desire for a similar product from S&W, the charge was $1 (in the early 30's at least), and presumably was applicable to an ordered gun. (This from Jinks in a letter on a .22 Outdoorsman.)
As an aside, your hammer does not appear to be of the "Humpback" variety. I have no idea what it is.
As another aside, I don't know enough about the geometry of the long/short actions to even began to be able to describe the differences---only to note there was the pre-war long, the post-war short, and the post-war shorter yet (by 24 percent on the SAO K-38). That leaves the short action on the pre-war 22/40 which I never thought to measure when I could.
Ralph Tremaine
And as yet another aside, the original name of the Single Action Only K-38 was Short Action Single Action K-38---which told the whole story. I have no idea why the rather important part of that name came to be omitted in later years.
...Ben
