Repair or replace broken VHS-C shell?
 

I have a box of old VHS-C tapes to transfer for my father. They play fine, and seem to have mostly been stored well, but a significant number of the tapes have an issue with the exposed gear spindle. I suppose because of the pressure applied to the gear, along with age, those spindles have actually snapped out of place. The gear can easily be pushed into the cassette, where any playback device would be unable to reach it. It is loose in the housing, rendering it unplayable despite the presumably fine condition of the actual tape.

It's clear my only course of action here is to crack the shells open and try to either fix the shell, at least long enough to capture the tapes, or go through the process of moving the spools to a different housing entirely. Perhaps I could thread multiple spools from broken shells into one normal sized VHS shell? Not sure what my options are here, and I don't know if this is something that is common.

If the VHS-C shells are beyond reliable repair that will not put the tape at risk due to sloppy glue, binding due to dimensional changes caused by the repair, etc. carefully respooling the tape to an empty full size shell makes sense. And once done you will not need a potentially problematic adapter.

I would only do one tape to a shell to avoid splices that would pass over the heads.

Find some full size VHS shells and sacrifice the tape in it to get an empty shell with spools. Practice the process with unimportant tapes first until you get it down.