Luger spring steel...

[John Sabato]

Originally Posted by sheepherder

I'm not sure that it was a 'setscrew' (although I haven't tried to read the text)...

Looking at the second drawing [below], it looks like a split nut, with the nut being spirally split...

From the pics, I can't figure out how Rolf adjusted it...

I had envisioned a long nut with a simple slot [for a screwdriver] and a threaded mainspring guide...You'd need outside access as well [a hole]...This actually sounds do-able...

A little imagination Rich... your description of how you envisioned it is actually how it would work...

What I glean from the engineering illustration images (and your description )... is that the spiral split in the nut would allow it to be twisted slightly during manufacture that would increase the torque with which the threads held the bottom of the spring guide when it was installed.

Sort of a self clamping lock nut, that would clamp hard enough to hamper drifting of the nut during spring tensioning and relaxing but could still be turned using the slot in the bottom to increase or decrease the amount of spring tension. A pretty clever idea if you have enough room to implement it.

You wouldn't need an outside "hole" for the adjustments as they would be seldom necessary once you achieved the appropriate tension. Initial adjustment would be made with the grips removed and a special spanner type wrench.

To quote the sheepherder,

Originally Posted by sheepherder

...This actually sounds do-able...