I designed and built my L-square edge stop around 1984, when I became frustrated with using stops for setting up stair steps for the process. I wanted one which was quick to install and easy to use (e.g., moved smoothly along the edge).
The tool in the picture was made for the Lumberjocks forum 2017, Winter Tool Swap. The ability to use it as a depth gauge and the extra locking hole to allow it to be used on the short and long legs of the L-square were improvements I added for the swap.
The current version has the previously mentioned improvements, plus the capability of being used as a table saw set up tool, and the magnets are, now, embedded in the body of the tool.
The improvements required me to:
1) add a threaded hole at the center and extending down into the groove, to allow the tool to be used on the short leg of squares;
2) drill a through hole behind the center threaded hole to allow a depth rod to be inserted through the body, just under the thumb screw;
3) drill three shallow holes into the body and into which magnets can be inserted for holding the depth gauge rod; and,
4) to use 3/4” square aluminum stock, so the stop will fit snugly in a standard 3/8” deep by 3/4” inch wide miter slot of a table saw.
For more details on building your own, go to Instructables at: https://www.instructables.com/id/L-s...-Set-Up-Gauge/