I've updated a sacrificial clamp design that I've been using which works rather nicely in maple:
The stock size this is setup for is 20mm tall by 40mm wide in cross-section, and the work area is 100mm long, so you can get a bunch out of a rectangular board of wood. Be sure to use a sacrificial layer underneath as the cut-out path cuts through about 0.2mm
The way it's sloped makes it so you can use it without a step-block on thin material, or only a small shim on thicker materials. Works nicely with my t-slot setup, and would work well for the threaded hole table as well.
ShapeokoHoldDownClamp.nc (383.0 KB)
This is to be cut on a Shapeoko3 at 24000rpm-ish with a single-flute 1/8" flat end-mill. You could just as easily cut it with a 2-flute tool at a slower spindle speed to keep the chip-load similar.
Old Clamp design holding down for the new clamp design:
New clamps in addition to some Kregg clamps holding down a large panel: