stubbing beach cobble and other awkward rocks

I wanted to cut a slot in the top of this rock to make a recipe hold (business card holder for those who don't cook) and I need to be able to take the rock out of the vice and turn it over so that the cut would be equal depth on both sides of the cut (instead of reflecting the curvature of the blade). Hence I stubbed it on the face of a long stub and flipped the stone over after the first cut and clamped to the other end of the stub. Yes I I had precut a flat spot on the bottom of the stone for gluing.



How round can the stone be? Well that depends on how round relative to how big the stone. Often if I have an irregular gluing surface (round or otherwise), I'll place the stone in the glue and then shim with wood splinters and wedges. The glue holds both the shim and the rock, and you can accommodate a multitude of surface irregularlities.

Brand name. I've use various, but don't go for the super water resistant ones. Right now I'm using Gorilla Glue's wood.carpenter's glue (not the foaming stuff, although it works to, but is harder to get off of the stone). Elmer's wood glue works for me too, but I firmly believe in an overnight cure and in real cold weather letting the cure be inside the house rather than in my supercold shop. I think the cold makes the glue more brittle and thus more likely to release from the stone. I've said it before but forgive a repeat. I reuse my stubs, but only after cutting off a fresh end for gluing to avoid mineral oil interference with glue grip. When stubs get too short, they become firestarters for my wood stove.