Internal ring gear

The ring gear for a planetary set, in whatever module you need

Ring with teeth on the inside, using the same involute profile as spur gears. It's the outer part of a planetary gearbox and the part that's almost never available made to measure: either you buy the whole gearbox or you go without it. Tell us the module and number of teeth and it comes with the internal clearance already built in, so the pinion fits and turns without sanding. It must share the same module and pressure angle as the pinion that runs inside it.