I finally went ahead and sketched up my own slip-joint design.  I like the old Fiddle-back or Coke Bottle style knives, so that is the aesthetic I was after.  This is the prototype, and mechanically, the action turned out pretty good.  I might go for a few thousandths more spring preload in the next one, but not enough to really change the design of the parts.

I'm going to reduce the diameter of the pins and move them in a bit on the next one.  These are 3/32" pins, and look a bit too large after being peened.  I might try 1/16" pins on the next attempt.

The blade is 2.5" overall and a two bar twist of crushed W's in 1095 and 15N20.  The scales are jigged bone with nickel silver bolsters and mild steel liners.  I made this one just to prove out the design, but it turned out well enough I'll let it out into the wild.

Very nice handle shape and blade  pattern.

Very nice work. 

This is the kind of work that reminds me that I am just a hack.

Splendid. Not to say that I can not, myself, some day aspire to this level, but Mensch, you have the chops!

Robert Taylor

This is gorgeous! Do you have any photos of it pre-fit up?

Thanks for the kind words guys.  Anachronist58, we are all just hacks in our own right.  The guys that start with dirt (ore) and make blades are the true masters.

Mason,  Here are the parts shortly before final assembly.  The pins in this pic were just fit-up pins.  I cut new nickel silver ones for the final assembly.

Here is an earlier shot that shows the interaction of the parts:

Thanks for the photos! I’ve been wanting to try to make a folding blade but am intimidated by all the fittings and locking mechanisms so I’m trying to absorb all the info I can!

Look for Steve Culver's book on the subject.  It'll tell you everything you need to get started.