In case anyone missed the old posts, after cutting out the parts I round the edges with a router round-over bit. The model radius corners are designed to fit the router bearing.
It is a good idea to drill a 1/16" hole at the bottom-center of the body into the axle hole to relieve air pressure, and for excess glue squeeze out when inserting the axle pegs.
Make a spacer from a plastic lid to prevent inserting the axle peg in too far. Punch a hole and cut a slit into the hole so you can just pull it out once the wheel is in place. Dale
You will get old if you live long enough!