Twin 624 Track Idler Sprocket
The free-running front idler (print 2) for the 'N20 Twin-Track Mini Tank Chassis' kit. It has the same 12-tooth, 12 mm-pitch profile as the drive sprocket: a Ø46 x 10 mm disc with teeth reaching Ø51.2. Its 18 mm hub holds two 624 bearings (4 x 13 x 5 mm) in 13.05 mm press-fit seats, one at each end, with a 10 mm lip between them. The pair spins on the hull's slotted M4x30 bolt axle and stays stiffer and better aligned than a single-bearing idler.
robotics kit tank-track idler