Fiat wooden knob madę from 3/8" (10 mm) birch plywood. Needs to be fiat so as not to hit the slider. Diameter 6 cm.
18.0
5/16" t-nut pressed into knob.
2" 5/16 stove bolt 1/5" washer
2" 5/16 stove bolt.
Depending on how you mount it, you may have to cut a few millimeters off the end of the bolts for the side to side stops so that the sliders don't collide with them.
Depth limit stops are similar to side to side stops but shorter.