Tooling/Barrel Tightener
Barrel Tightener
There is rarely a need to use a barrel tightener in modern watchmaking and watch repair, due to the precision and ready availability of parts for watches. There is still a place for it in the restoration of vintage and antique timepieces, however.
A barrel tightener is used to close the diameter of the barrel lip that hold the barrel cover. The barrel cover is not fixed by any means other than friction and the tension that this lip provides, so the fit must be tight. In circumstances where this fit is not tight enough to hold the barrel cover in place, which can become the case after decades of service, the lip must be tightened evenly all around its circumference. This is achieved with a barrel tightener by setting the barrel into the tightener (pictured below) with the lip facing down into an appropriately sized hole in the tool; the hole should be wide enough to accommodate the barrel, without the barrel touching the bottom of the tool. A broad dowel of hardwood, such as boxwood or oak, is then held, level to the tool, on top of the barrel and tapped lightly with a hammer. The barrel is then removed and the fit of the lip is checked against the barrel cover. This process may be repeated as many times as necessary to achieve the desired result.
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