Maybe we should have a “tips” area for things like my bricks-on-a-bungee and this.
I’m going to get a 4x8 piece of hardboard (it’s cheap - compared to plywood) and put it between my Malsow surface and the material to be cut.
It won’t be automated (my ancient Craftsman router refuses that idea), but when I see brown chips coming out, I’ll know I’m at “thru” depth, and I won’t have to worry about really messing up the surface of the Maslow.