So, I assume people know about Sig's folding stocks and braces they sell? Basically, they attach to a small chunk of Pic rail. I liked it because the hinge mechanism was so short and compact. Some of these hinges look like they ad 1-2" of length to the pistol.
http://store.sigsauer.com/sig-sauer-folding-sbx-kit-mpx.html

Well, I picked up the folding Sig Brace kit, thinking it would go great on my M92. Any thoughts on how to attach some Pic rail to the rear of the gun? Drill, tap, bolt? Get some steel rail and weld it on?

Thoughts?

I drilled and tapped two holes for my Stormwerkz hinge and it mounts very solidly.

Drill, tap, bolt

not sure on the brace, but I use a Sig Skeleton stock on my SBR.  I used a section of aluminum rail, I drilled and ran a bolt through as well as used 3M panel boding epoxy.  Might as well be one piece of material.

Double post

Should have just gotten one of these:

http://www.usmachinegun.com/proddetail.php?prod=M92-UFB

-No permanent modification to your gun

-Shockwave brace is A LOT slimmer than the Sig brace. Makes a huge difference when folded.

-cheaper

Got the same mechanism from Us Machinegun and it is solid. Glad I bought it