[nuclearnerd]

Here's how we used a disc brake on our 2015 robot "Guillermo"s elevator. The brake allowed us to hold a stack without having to keep current on the motors, and with a faster gearbox than would otherwise be necessary to prevent backdriving.

Mounting was reasonably easy. We modified an Andymark hub (slotted the holes a bit) to match the rotor hole pattern then slid the rotor over the end of a hex shaft. We made up a plate to mount the caliper. The cylinder (a 3/4" bore, 2" stroke iirc) was mounted on a bracket remotely, connected to the caliper with a bit of brake cable and housing.

I think 1678 (and probably others) used a disc brake on their climber this year. We considered one too, but ultimately just went with a single use latch (since you only climb once in a match.