I wanted to use this puzzle box to give little gifts to my kids so I wanted to put one or two $1 coins in it. When I changed the diameter, it ate into the tooth and the puzzle didn't work.
I remixed it a little so that some of the measurements would be based on the diameter of the coin. It should work for any coin size larger than a US Nickel (just under .9 inches or about 22.9mm).
I have not tried it with smaller coins. It may need a minimum length constraint so that rotating the puzzle pieces doesn't expose the slot for the bead.
In any event, change the coin_diameter or the coin_depth and you should get a puzzle with appropriately sized cutouts. There's a small margin built in, but you can adjust to your hearts content.
This is a super clever concept. Much appreciation to the original designer, scorch!!
For assembly instructions, check out the original design: