Monday, March 19, 2018

Heat treatment of watchmaking micro-components

Regardless what kind of metal machining shop you intend to setup and what is your intended product (a car engine or a watch!) your ultimate goal is to enable yourself to do certain tasks and processes. Starting with relatively simple ones: To draw and measure. The ability to hold and grab firmly and accurately is the next goal. Then to cut, drill and tap, weld and solder. From then on, you are moving into more serious operations which require sophisticated machinery: turning, milling, grinding.  Obviously your product has to look appealing so you should invest in deburring and polishing equipment as well. Another sometimes overlooked aspect of metalworking: The ability to soften or harden metal. And this is precisely where we are right now.

A number of  steel watch parts (stem, levers, screws, arbours) undergo both pre-machining and post-machining heat treatments. A typical furnace has to provide not only a relatively high temperature (up to 1100 C) but the temperature has to be constant within a very tight range over a very vast spectrum from 100 C to 1100 C. In addition, the parts compartment must remain oxygen-free during the entire process. A quality furnace would also incorporate an oil quenching tank and shielding with inert gas. Yes, while the basics of metal heat treatment are rather simple and well-known, watchmaking furnaces are fairly complex performance-wise.

Taking into account our low volume and part size we have opted for the smallest furnace by Borel. (Don't be fooled with its size - it weighs almost 200kg!) Borel is a Swiss manufacturer which supplies equipment to all the top Swiss watch brands. The company was founded in 1918 by Dr. Charles Borel. As of last year, Borel is a division of SOLO Group, located in Porrentruy, Jura.

If you are a watchmaker or machinist specialised in micro components which require heat treatment then we would be happy to assist - especially if you have issues with scaling and oxidation.  Contact us at

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