Brass Synchro Cone Ring: Turned with a Taper Matched to Its Seat

In a synchromesh gearbox a cone-shaped brass ring on the gear is pressed against a cone on the sliding collar, and friction brings the two to the same speed before the teeth engage (Wikipedia, Manual transmission). Factory rings are forged or pressed from brass or steel; this one is turned from brass bar, with its cone and the seat it runs on cut at one lathe setting so the tapers match. Method and sizes are ours. The picture: our drawing.