Roller Chain Sprocket (06B, 17 teeth)

A sprocket for 06B roller chain — 3/8in (9.525mm) pitch, 6.35mm rollers, the common British standard size. 17 teeth, 51.8mm pitch diameter, 56.7mm over the tips, 5mm plate, 8mm bore. The tooth form follows ISO 606: the seating curve the roller actually beds into is 3.21mm radius (0.505×roller), swept through a 134.7° seating angle, on a root diameter of 45.5mm. Two things are worth saying plainly. ISO 606 is behind a paywall, so the tooth form here is taken from its verbatim reproduction inside granted patents and cross-checked between two of them; the seating curve — the part that matters, because it is the only part the chain touches — is corroborated, while the topping curve could not be sourced at all and the teeth are simply topped on the ANSI outside diameter instead. That is a real simplification and a small one: tip length is not what makes a chain mesh. Prints flat, no support. PETG or nylon — a sprocket in PLA will shear a tooth off under a shock load.

from £3.11example, in PLA