Smith-Alexander .220 radius high ride with a bunch of material removed to match the tangs. I think I would need to get the tangs welded up to use a .250. May be why the frames were a deal, or maybe there was a different beaver tail out there that is super high ride. Much more and it would get into the thumb safety hole.
First. The Chen gen 2 uses a officer MS and officer MSH pin location, and the well is one piece with the MSH. Still cuts into the frame. They also have an “SI” version but that one adds length/ no cut.
Couldn’t find any .005 ribbon silver solder, everyone out, ( supply chain/ covid/ WWIII, etc) so went with the gen 2.
I started out with a HF. Added DRO’s, power feed, belt drive, limitation was always the footprint of the ways being so small just couldn’t get a rigid table. (Well, and, it was a HF) Still turned out some pretty cool projects.