40mm x 40mm x 20mm cnc touch plate for cnc / mill plenty off info out there on how to use these but could not find a stl file so I made one. Usually they are a solid aluminum block but a little CA glue and aluminum foil and you have yourself a nice touch plate.

if you want to use and it is fully intended glue separate pieces of foil on the block for x,y, and z

three holes are included 2.5mm with a depth of 8mm so a M3 x 6mm or 8mm will work for attaching your probe / end stop wires