Thanks! I think i need to switch the steel guide in the back with aluminum or at least coat the holes in solder as the steel on steel is a bit rough, maybe it will smooth out. The stones will be interchangeable with that hard plastic version of velcro that is the same on both sides, seems sturdy enough not to let the stones move. And I still need to make a steel plate to stick to the magnets with small clamps for doing little short-height blades the magnets alone won't hold over the edge of the frame. There will be a bit of fine-tuning for sure.