Cleaning the dismantled movement

Once all repairs have been done, the movement should now be cleaned. Some repairers clean before they begin work, but the amateur will have found the marks where parts were fitted a help in locating them while working on the movement. These marks are a great help in identifying the finished shape of missing parts.

To overhaul a platform, very carefully strip it down using watchmaker's screwdrivers and a pair of tweezers. Never put any pressure on any of the delicate parts or distort the hairspring. Clean the parts very carefully in hairspring degreaser and re- assemble when dry. Do not oil the hairspring or associated parts, but you may apply a very slight trace of watch oil to the pivots.

When re-assembled, the platform must tick evenly and this is effected by adjusting the position of the collet that connects the hairspring to the balance wheel.

To clean the rest of the movement, make up a solution using one of the proprietary cleaners. Remove the covers on barrels by inserting a tool into the hole provided. Often a punch mark shows the correct position of the cover in relation to the barrel. Ideally the springs should be removed for cleaning. The amateur may have difficulty in removing and replacing a spring without distortion. Seek the help of a repairer with a mainspring winder. To remove a spring from a barrel without a winder, first remove the cover and the arbor. Using a pair of strong leather gloves to protect your hands, grip the centre of the spring with long nosed pliers and pull it out enough to get a grip of - say one turn. You will now be able to unwind it bit by bit until it is all out. Avoid letting the edge of the spring touch the coils in the barrel as you turn it as the polished edge will be damaged. It will also make splinters of steel which can be dangerous. You will find the removed spring is now slightly spiral, caused by pulling it out. Mainspring winders eliminate this problem.

Examine the eye of the spring for fractures. A new eye can be made by softening the end of the spring in the flame of a torch and punching and filing to shape. Although this is often thought of a suitable job for the amateur, the spring has to be heated to precisely the correct temperature -too hot and the material will tear and too little will cause a subsequent fracture. Only do it if a new spring the correct length is not available. Heat until a dull red and allow to cool gently.

Experience shows that once a spring reaches the stage of fracturing, it is better to replace it. Tired or weak springs should also be replaced at this opportunity.

Avoid flat areas resting on the sides of the container. A wire sieve is useful for suspending small parts. Some can be wired together for convenience. Soak the parts until clean and rinse thoroughly in warm water. Rust can be removed from steel parts by using proprietary rust removers and/or fine emery. Dry thoroughly in warm air and prepare for re-assembly.

Many clock plates contain information inscribed by previous repairers and as this is of historical interest, mechanical buffs should not be used. A recognized method of polishing involves brushing the brass-work with a brush soaked in a shallow tray of brass polish. Rinse each piece in a bowl of paraffin or clock rinsing fluid and dry. Many repairers dry the parts in sawdust and brush them clean with a soft brush, occasionally drawn over a block of chalk. There are many different methods, many of them very old, for doing this task. Repairers have their own favourite ways of doing things and each has its pros and cons.

Repairing Your Own Clocks by Mervyn Passmore