OK, I'm going to play the "Dummy" for everyone.
Bob, please explain the differences and advantages, mechanical or aesthetic, between the parts Chambers originally supplied with this lock and the parts (and Tuning?) that you supplied. 
Thanks in advance.
Another name for the link/stirrup came from the English. They called it an anti friction swivel.
A look at the mechanical function of the swivel vs the old style where the mainspring bears on
a ramp is that fast action is available with less lift/compression of the mainspring when the lock
goes to full cocked.I do little "tuning"to these locks after they are done. This particular one only required a slight relieving of mainspring tension by a few file strokes on the upper limb retaining stud where it goes
under the bolster.It is smooth,fast,produces good sparks and has zero over travel. When it clicks the second time it's ready to go.
I am convinced that a good forged spring has a whipping action that isn't obtainable with a cast spring.
Also I do not worry about production or expedients to get done in a hurry.Production work is fine and without it none of us would have much of anything but I have done it in other venues and it holds no interest for me.
The job in my shop is done when it's done,not before.
Bob Roller
