I've made them from aluminum tubing.
Hard to explain, but essentially it's two nuts (front/back) recessed into the bottom of the comb that's been cut. Piece of aluminum tubing at each location, cut in half- but at about a 45 degree angle. A long allen head screw with diameter that'll pass through the tubing (but the head will not) is passed through the assembly into the nuts recessed into the bottom of the cheek piece.
There are two holes slightly larger in OD than that of the tubing running vertically the full depth of the stock that align with the locations of the nuts in the cheek piece, coming out the very bottom of the toe of the stock.
With the screws being slightly loose, the cheek piece with the aluminum tubes attached just drops down into place. With the cheek piece at the desired height, run an allen wrench up through the bottom of the toe, lightly tighten the allen screws. This causes the angled tubing sections to expand against the walls of the hole, and locks the comb in place. Loosen, adjust, re-tighten as needed.
I'll see if I have some of the tubing lying around in the shop to make up a quick example of it. Simple to do, but it's critical to get the through-holes perfectly vertical lest they come out off-center in the toe of the stock.