We built our own worm drive in 2011 and it worked really well. Got the gears from McMaster Carr. They are heavy and we could have gotten by with lighter gears but these were easy to get. Stock Drive Products has a good selection of worm and gear combinations. See
https://sdp-si.com/eStore/CoverPg/Gears.htm.
We made a simple box structure to hold the gears from aluminum bar stock and bronze sleeve and flanged sleeve bearings which work fine in this application.
We used a CIM attached to an AndyMark micro gear box with the worm mounted directly on the output shaft of the gearbox. The shaft of the wheel gear carried a bicycle sprocket mounted on a plate attached to a shaft collar. A bicycle chain ran our very effective long arm to scoop up and hang the tubes in that game.
If we use a similar arrangement again this year, I would probably design it around a channel to hold the worm, with uprights to hold the wheel to reduce the machining.
Dr. Bob
Chairman's Award is not about building a robot, every team builds a robot.