[shewejff]

Worm gears rock, but my recommendation would be to go to a smaller drum. You are putting too much torque through the worm gearbox. A small drum and a large drum have the same force exerted on them from the wire (the weight of the totes), but with a smaller diameter you will have less torque on your gearbox which will result in less contact force between the gear and the worm, which should result in less wear. You'll just have to spin it faster which is no problem just by tweaking your Versaplanetary ratio.

We are using worm gears (steel H1407RH worm with bronze DB1400 gear, 10:1 gear ratio) with a CIM mounted to a 3:1 Versaplanetary with a 1.29" diameter sprocket as output. We aren't having any issues lifting the totes. We also used a very similar setup a couple years ago to lift our whole 100 lb robot to climb the tower. We had no noticeable wear at all through two competitions.

We made our gearbox out of a 2" X 3" X 1/8" rectangular aluminum tube. That works really well for the size of our gears, but the holes really need to be drilled perfectly. With our rudimentary workshop tools, it took us a couple tries to get it perfect.