An earlier dummy assembly of components ET 60/1, PD2, PD4, and lastly, PD 3/2 should be done with all three alternative lobe machinings tried to ascertain which gives the least play and smoothest functioning lobe faces against each other. What is desired is the least (or nil) movement when the outer PD 3/2 is pressed firmly home and against its mates on ET 60/1. The choice of mating position should all be felt, as, firmly home, the sprocket is rotated both left and right while you search for that choice which results in the least movement without an immediate rise of PD 3/2 as the lobes are forced apart.

This pre-assembly process ensures that when bolted up the spring pressure drives the lobes fully into deep engagement, allowing no free "give" without constant spring pressure. In the absence of such a fit, uncontrolled back and forth movement occurs, resulting in rapid wear and chipping of these hardened surfaces. Roughness and noise results, as well as a loss of sweetness. Two spots of paint adjacent to the selected mating position will aid final assembly.

Be sure all springs are fully seated. Next, with all surfaces lubed except the threads on both shaft and nut, and a bit of removable Loctite on those, final assembly is carried out, preferably with a quality socket, ground flat on its face for maximum purchase, using medium air and an impact tool. "Do it up" till it ceases to move and then stop. Enough. More applied carelessly may move the shaft in its fly wheel bore, sheering the mills pin.