Basic elements › Machines & tools › Hand tools

THE ALCOHOL LAMP (or oil lamp)

What is the use of the alcohol lamp?

The alcohol lamp — sometimes oil-fueled — is one of the oldest sources of localized heat used by the horologist (watchmaker). Although contemporary workshops have gradually adopted precise, programmable electric furnaces for carrying out industrial heat treatments, the lamp remains a familiar tool for the artisan horologist (watchmaker) and the restorer, who appreciate its simplicity, its autonomy, and the sensitivity of the flame it produces.

In its classical form, the tool consists of a reservoir — often made of Glass (crystal) or Brass — topped with a metal burner fitted with a Drill bit made of absorbent fibers. A Regulation / Adjustment Screw controls the height of the Drill bit and, consequently, the size of the flame. This, when regularly maintained, provides calm and clean heat, without spattering or excessive soot production: essential qualities for working parts whose dimensions and surface condition tolerate no contamination.

The thermal uses of the lamp are multiple. Tempering — which consists of controlling the reduction of the Hardness of a part made ofSteelpreviously quenched in order to give it a sought-after compromise between Hardness and toughness — is among the most classic operations. The part is placed on a Brass plate or in a bed of Copper shavings, above the flame, and the Horologist (watchmaker) follows the oxidation tint to estimate the Temperature reached. It is according to this same principle that the Bluing of Screws and certain hands: the horologist precisely interrupts the heating upon the appearance of the desired steel blue — generally around 300°C — in order to fix this hue charged with visual identity, which also contributes, incidentally, to protecting the component against corrosion.

Other operations also rely on the lamp as their heat source: the local annealing of a component that one wishes to make more malleable before fitting work, the reheating of a part to allow its hot fitting or removal, or even the controlled melting of the Shellac used to fix the pallets of the lever or for repair operations. For all these interventions, the oil lamp offers the advantage of immediate use and manual regulation which, in the hands of an experienced horologist, remains surprisingly precise.