You can go to your local hardware store and for less than $10CAD buy a 2x4 and some screws. (The price goes up considerably if you have to also buy a drill and/or saw).

Build the box yourself, and you can use a saw to chop out the curve.

Better yet, cut the 2x4 in half and lay the pieces parallel to one another, 0.5 inches wider than your putterhead.

Then don't touch the wood.

Build your own damn muscle memory - plus with this method, your muscles also remember which small muscles have to work to keep the club online.