This plate can be used flat on the mill bed or it can be held in a vise. The small block may be positioned on the under side of the plate in various positions and then that can be clamped in the mill or bench vise as needed.
The two steel plates may be used for clamping using the eccentric low profile clamps or used as a reference for placing the part and using strap clamps to hold the part down.
This plate was also made using my CNC Router. Designed for wood but she cuts aluminum very well. I am working on a new spindle (low speed) so I can use larger milling cutters with it. Here is the link:
Counter bored holes are for mounting on the lathe bed directly while the block needs to be bolted on the underside so that it may be used in a vise. All tapped holes are 1/4-20. The plate is 1" thick so even if I chip into it a few times it can be resurfaced on the CNC in short order.