If you’ve been in the RC hobby for any length of time then you have definitely seen the ads above. Back in the day when brushed motors were the only choice your commutator would wear out from the brushes riding on it. Eventually you’d need the comm resurfaced which is where the comm lathe came into play. Stroll up the aisle of any RC car track in the 80s and 90s and you’d see these things on every single table.