Universal Head
American Watchmaker and Jeweler (1892)
The universal head, shown in Fig. 308, has entirely superseded the clumsy universal mandrel in this country. It is more accurate, less clumsy and complicated and will perform the same work. The face plate is 3 1/2 inches in diameter, but by the use of two crescent-shaped slots, it will hold anything in size and shape of watchwork. The pump center is operated from the back by the rubber knob and can be used either with or without a spring. The jaws, which will pass the center, are held in position on face plate by springs, and are fastened from the back. Peep holes are provided in these heads in order that the workman may examine the back of the work at all times. In the Moseley head, shown in Fig. 308, these holes are of taper form. Fig. 309 shows a universal face plate to be used on chuck in lathe. It is smaller and less expensive than the universal head and answers very well for some work, but cannot be recommended very highly, as it is not as accurate. The pump center is used to center from the back any object confined in the jaws, but it sometimes becomes necessary to mount the object by means of wax upon a plate and hold the plate in the jaws. In such a case the work must necessarily be centered from the front. This can be done accurately by means of a piece of pegwood, as ordinarily done on the lathe, by placing the point in the center hole and the pegwood resting on the T rest, and observing if the free end of the pegwood remains stationary. See, also, Centering Tool.
What Has Changed in the Last Century
When the American Watchmaker and Jeweler described the Moseley universal head in 1892, it had just "entirely superseded the clumsy universal mandrel" — and the tool it describes is still recognisable on a watchmaker's bench today, with independent-jaw faceplates, pump centres, peep holes and wax chucking all still in use on 8mm lathes built to the Webster-Whitcomb pattern that became the trade standard. What has changed is the work rather than the tool: watch parts are now cut on CNC and Swiss automatic machinery, and the collapse of mechanical watchmaking after the quartz movement arrived in 1969 turned the bench lathe into an instrument for repair, restoration and hobby work. Original Moseley heads are now mainly bought secondhand by restorers, and the advice on centring with a piece of pegwood on the T rest would still be given straight-faced in a modern workshop.
Written for this edition, 2026.