In fitting a new barrel arbor to a watch, first centre a rough barrel arbor by filing a centre on each end. Affix a screw ferrule to one end and turn the central portion to a diameter equal to one-third that of the internal diameter of the barrel. Then turn one pivot to nearly fit the barrel bottom, and a second pivot to fit the plate. Reverse the ferrule and turn the other pivots. Then drill the hole for the mainspring hook. Harden it, and temper to a blue colour. Now place it in the turns again and finish all the pivots to fit their holes, and polish them first with oilstone dust and oil on a flat steel polisher, and finally with crocus and oil on the same polisher.