Uncomplicate complications – Finishing #1

Aaron Becsei is an independent watchmaker, and member of Académie Horlogére des Créaturs Indépendants. He guides me with the experts’ knowledge through the secrets of fine watchmaking. In the series of Uncomplicate Complications we discover the seeds of uniqueness, art and value in a timepiece.

Watchmakers depending on the price range, their passion for perfectionism, taste, skill and technique may spend more or less time with finishing, creating rather minimalistic, but functionally good or more elaborate and artistically distinctive parts. Masters of Haute Horlogerie put tremendous energy and attention to finish even the non-visible parts to the highest standards.

Classifying the finishing techniques is not uniform. One can treat the surface mechanically (abrasive roughening or smoothing) or by non-mechanical methods, such as chemicals or heat. In this article I’ll cover few commonly used abrasive roughening touches and in the next post I’ll focus on smoothing processes. I will leave the non-mechanical methods out for now.

Abrasive roughening techniques produce different patterns of decorative scratches on the surface without removing a significant amount of material or notably reshaping the component. Besides Côtes de Genève (covered last time) which is produced by rotary motions within the parallel stripes, there are other popular methods.

 
Matte / satin finish
The essence of  matte/satin finish is creating a homogenous, uniform surface on various parts of the watch. It is achieved by a wire brush or by rubbing the part on a glass plate. When prepared on a glass plate the part is smoothly pushed into the graining paste on the glass so that the graining particles are not leaving scratches but they are rolling on the surface.

 
The graining finishing techniques are the comprehensive group of methods.

Perlage
The machine has a rotating abrasive stick and Aaron makes circles one by one with overlapping concentric lines. This type of decoration is hard to achieve and calls for expertise and tremendous control but the result is the beautifully sparkling effect of the material. Perlage is often used to decorate other engineering works of genius – probably one of the most well-known is Lindbergh’s Spirit of Saint Louis from 1927.

 
Linear / circular graining
Although Perlage and Côtes de Genève are very appealing decorations, many say that creating a delicate finish via linear/circular graining requires even more steady hands, as any micro scratch that the previous would hide, here becomes visible. Linear or circular graining is done by using abresive particles to apply fine parallel scratches on the surface along a line or a circle.

 
Snailing
Snailing is a spiral-shaped pattern produced by circular arcs on ratchet wheels and barrels that gives an animation and depth to the surface. This type of decoration is achieved by a rotating wooden grinding-wheel turning over the surface of the rotating part, starting from the centre and moving along an arc. Depending on the character of the arc and how the grinding-wheel touches the surface the “snail” can have different patterns.

 
Sunray-graining
When preparing the so-called sunray finish the watchmaker uses a wooden disc, and starting from the centre moves along the surface in straight radial motions.

 

The articles of the series:

Uncomplicate complications – Entrée
Uncomplicate complications – Movements
Uncomplicate complications – Anglage
Uncomplicate complications – Geneva stripes
Uncomplicate complications – Finishing #1
Uncomplicate complications – Finishing #2
Uncomplicate complications – Tourbillon
Uncomplicate complications – Perpetual calendar
Uncomplicate complications – Power reserve indicator

Photo credits: Bexei.
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