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THE MICROMETRIC REGULATOR SCREW

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1. General description

The Micrometric regulator screw is an optional component inseparable from the Swan’s neck.

It allows a precise Regulation / Adjustment of the watch’s rate (advance or delay) to be defined and maintained. The Micrometric regulator screw passes through the heel of the Swan’s neck in which it is screwed. The Swan’s neck presses the arrow of the regulator against the end of the micrometric regulator screw. The thread pitch of the regulator screw is very tight, allowing a very fine adjustment of the position of the regulator’s arm. By holding the regulator’s arm against the micrometric regulator screw, the swan’s neck prevents any unwanted misadjustment, particularly during shocks.

Figure 1

Plan of a micrometric regulator screw

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Figure 2

Assembled micrometric regulator screw (interaction between regulator and swan’s neck)

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2. History

It is difficult to date the appearance of the Micrometric regulator screw and the Swan’s neck. This is even more true when it comes to attributing its paternity. The first systems observed date from the 18^th century. However, the use of such systems saw its rise between the late 19th and early 20^th century.

3. Handcrafted manufacture of a micrometric Screw

Made of Steel, the Micrometric regulator screw is a component relatively easy to make, regardless of the method used. The craftsman begins by performing all the turning operations that make up most of the work. The craftsman can use the same Lathe to thread the Screw. The head of the Screw is then decorated, then subjected to Heat treatments (quenching and tempering). Heat treatments of the micrometric Screw are relatively difficult to achieve successfully due to its considerable Length and its small diameter. Thus, the heat treatment may not be homogeneous and unfortunately deformations of the Screw are always possible during these steps. A brief step of Polishing and softening will whiten the Screw again, which will then be ready to be assembled.

4. Industrial production of a micrometric Screw

The Automatic lathe is the most appropriate machine to produce Micrometric regulator screws, regardless of quantities. All operations (turning, Threading and Milling of the square, when there is one) can be performed there in a single cycle. Depending on the chosen Alloy of Steel, the micrometric Screw will not require heat treatments later. Finally, depending on the level of finishing chosen, the finishing touches, and in particular the polishing, may be carried out by hand or more industrially in bulk (in a polishing drum, for example).