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Mervyn Passmore 2005
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Many amateurs suffer from extreme lack of tools and cannot justify the purchase of specialist ones at the start. In particular, cutting broaches are hard to choose. You will need broaches to suit any bushes you fit.

Looking at bush size charts you will see many sharing the same outside diameters. For example, many have outside diameters of 4.50mm. Looking at a list of broaches, number 14 in the Stubbs gauge has a maximum working diameter of 4.57mm. This broach will enable you to fit this bush with ease.

Simply repeat this exercise for any bushes you expect to fit. Broaching the inside of new bushes will depend on the pivots themselves. You will need to buy several for your first clock, but as your range builds up, you will be able to bush almost anything from stock. The reason no one sells 'all the broaches you're likely to need' is because this depends on the kind of clocks you work on. Carriage clocks use a quite different range to longcase clocks.

A 5 sided cutting broach

Cutting broaches are five sided, and tapered. The measurement given in catalogues is the effective diameter of this 5 sided cutter, about 10mm from the shoulder. The taper is 0.01mm. so the diameter decreases about 1mm per 100mm in length. If the length is listed in the catalogue, you could, if you wished, estimate the starting diameter.Select a bush simply by identifying the smallest one that can be used, and whose length is greater than or at least equal to the thickness of the clock plate. The outside diameter of this bush dictates which cutting broaches you will definitely need. You will need others to complete the work. Bergeon bushes increase in diameter in regular steps: