The CLOCK REPAIRER'S MANUAL E-Book

Mick Watters

• Herausgeber: Crowood
• Kategorie: Lebensstil
• Sprache: Englisch

Seitenzahl: 294

Veröffentlichungsjahr: 2011

Beschreibung

In The Clock Repairer's Manual, Mick Watters explains how to approach all aspects of clock repair, maintenance and cleaning with confidence. For anyone who has ever considered clock repair as a hobby or a profession, as well as those under initial training and for the existing repairer, this comprehensively illustrated and detailed manual will be a useful reference.Topics covered include the typical clock movement; dismantling, cleaning and reassembling; striking and chiming clocks; repairing worn pivots and bushing and escapements, staff fitting and jewelling.

Leseprobe

CONTENTS

Title Page

ACKNOWLEDGEMENTS

PREFACE

1 GETTING STARTED

2 THE CLOCK MOVEMENT

3 CLEANING A SIMPLE CLOCK MOVEMENT

4 THE PENDULUM AND ASSOCIATED ESCAPEMENTS

5 THE WATCHMAKER’S LATHE

6 REPAIRING WORN HOLES AND PIVOTS

7 STRIKING CLOCKS

8 ALTERNATIVE TYPES OF STRIKING CLOCK

9 CHIMING CLOCKS

10 WEIGHTS, SPRINGS, STOP WORK AND THE FUSÉE

11 PIVOTS, JEWELS AND PLATFORM ESCAPEMENTS

12 FURTHER PLATFORM WORK

13 PART JOBS

14 GEAR CUTTING

USEFUL ADDRESSES

Copyright

ACKNOWLEDGEMENTS

I thank Cynthia Boult who was consulted over the cover, colleagues at St Loye’s College Foundation, particularly Peter Mitchell and Mike Western for their advice and support on technical matters, and to the trainees of St Loye’s College through whom I have learned so much.

PREFACE

This book was written primarily for the horological enthusiast interested in taking that first step into clock repairing and for those under initial training in clock repairing. There is likely to be material which will benefit the professional repairer as well. For example I have never read in any book how to splice a twelve strand long case clock rope. It is included here.

Those completely new to clock repairing will be led gently into new skills and knowledge. It is the intention that this book will inform about techniques and give you the confidence to have a go. It is also the intention that those with limited experience will extend their ambitions.

You will find here a mix of imperial and metric units reflecting the speed of change within industry generally. For example, steel continues to be supplied in imperial units so don’t be surprised if you are asked to select ⅛inch brass and set up in a Number 32, (3.2mm), collet.

1

GETTING STARTED

Two early considerations for those preparing to repair clocks from home, whether as pure enthusiast or professional, are where to work and what tools will be needed to make a modest start.

Where to work will include alternatives such as a shed, an outhouse, a loft conversion, a utility room or a garage; otherwise an existing workshop might be converted, or the lounge, dining-room, kitchen or even the bedroom utilized. Perhaps initially working in a bedroom doesn’t seem realistic, but in fact making or converting a double wardrobe into a work station is very sensible. There are significant advantages to working in a bedroom: there is minimal disturbance from other users of the house, and work in progress may be left from one day to another – yet to anyone entering, the work station would appear to be an ordinary double wardrobe.

Certainly working inside the house offers the advantage of comparative warmth in the winter months. The disadvantage of working in a lounge, dining-room or kitchen is having to clear things away even as work progresses.

Next to be considered are the workbench, storage space, light and a chair to sit on.

THE WORKBENCH

Many hours are likely to be spent sitting at the workbench, so it must be the right size and shape for your comfort and health, and strong enough for the work that is to be undertaken. It should enable you to work occasionally with both elbows resting on its surface, and with an upright back.

A good height for a clock repairer’s bench is about 92cm (an approximate conversion from the traditional imperial height of 36in). A minimum width should also be about 92cm (36in), though if room permits, a bench 107cm (42in) wide would allow a small vice to be permanently attached to the bench top at one end; it would then be available for immediate use but without getting in the way during other bench work. The depth of the bench should be a minimum of 46cm (18in), but 61cm (24in) if space permits; this will allow for the work in hand and offer room for various tools that will be needed as work progresses.

The bench top should be about 2.5cm (1in) thick, or more if possible, to take light hammering and heavy clocks. The surface should be covered with plain brown or light green cork lino or a plain vinyl; it is better to make the surface as plain as possible so that small parts can be seen easily on the surface. The sides and back of the bench should have high edging to contain items on the bench, and the front should have a low edging, for comfort yet also to prevent items from rolling off.

Small drawers under the bench will help with storage for tools and materials. The storage should be well off the floor as it is essential to be able to sweep under the bench to find small parts that will inevitably find their way there. Every potential clock repairer should be aware that small clock components can spontaneously grow both wings and legs and will discover the most inaccessible places to hide in.

The bench should be well lit, with either a twin balanced fluorescent tube lamp or a tungsten lamp with a 40 watt pearl bulb. A stronger bulb will have the disadvantage of throwing out too much heat. Some repairers advocate working by a natural north light, but this is far from essential. Working with sunlight falling directly on the bench is very uncomfortable, not so much because of the heat but because of the uncomfortable light. A blind should overcome the problem of direct sunlight falling on the bench.

Finally a working surface, often of plain white A4 paper, is secured to the bench in front of the repairer.

If the luxury of a purpose-built, dedicated bench is not possible, a table top will do, although raising the working level with blocks or a false top will be more comfortable. The surface of a table top will need protecting to avoid scratches.

A further space with a working surface will be necessary for clock cleaning and other dirty or heavy work. Certainly an outhouse or garage is better suited to some work, but is not essential for a modest start.

Working heights vary so a chair that can be adjusted between about 46cm and 61cm (18 and 24in) should ensure a comfortable working position. A back to the chair is preferable.

TOOLS

For anyone just beginning in clock repairing, the thought of a significant outlay on tools would perhaps be off-putting. In fact much can be achieved with ordinary tools found in the home. Inevitably as knowledge and skills are gained, the desire for specialist tools will increase; but these can be acquired over a long period, perhaps being paid for by repairs carried out.

Tools need not be new, of course, and the repairer is encouraged to attend some of the many horological tool auctions held across the country. British Horological Institute branches often hold local auctions which members of the public may attend; BHI branch secretaries will have advance notice of pending auctions, and their addresses may be obtained from the secretary of the BHI.

Fig1Anidealclockrepairer’sbench.

Fig2Aclockrepairer’sbenchlaidoutwiththetoolsinconstantdailyuse.

The absolute minimum needed to get started will be small flat nose pliers, a variety of small screwdrivers, one or two small plastic containers to hold parts, and a pair of tweezers. For those who wish to purchase a more comprehensive range of specialist tools the following are recommended, and should cost no more than the equipment needed for many other activities such as archery, fishing, mountain biking or photography. These may be purchased from tool and material houses or from second-hand sources.

Tool List

Tweezers, general purpose

Set of watchmaker’s screwdrivers, 3mm to 1mm

Two oil cups

Essence jar, 60mm (2.5in)

Brush, four-row

Movement blower

Bench knife

Material tray

Clock hammer, 50g

Screwdriver, 180mm × 5mm

Set of four oilers

Eyeglass, single

Eyeglass, double × 10

(spectacle type for those who prefer)

Pliers, flat-nose 115mm

Pliers, round-nose 115mm

Top cutters flush 115mm

File, 150mm (6in) No4 double cut

File handle

Other tools for various repairs will be identified as they become necessary.

Tool Care

Now a few words about the care of tools. Those not in constant use should be kept close by in drawers, leaving the bench free to carry out the work in hand. Tools that need special care include tweezers, screwdrivers and oilers; these are also the most used and abused.

Tweezers are used more than any other tool, and if properly looked after will save you having to spend hours searching for parts which otherwise will fly out of them. Use them for dismantling, assembly and balance spring adjusting. Avoid levering and prising with them, and any activity that might bend them. When the points are squeezed together, they should remain in contact for some distance back from the point; if they are bent out or in, any parts you are attempting to hold will in fact fly out of them. Tweezers are dressed by grinding and filing roughly to shape, then emery cloth is used round the outside faces to give them a pleasing appearance. Avoid touching the inside faces altogether.

Fig3Awell-proportionedscrewdriver.

Fig4Theoilerfiledtoagentletaper(a)andflattened(b).

The best screwdrivers are hardened and tempered to dark blue. Screws used in horology, even with the same tap size, often have differing width slots so it is necessary to sharpen screwdrivers with this in mind. To sharpen, the screwdriver is placed in the bench vice and filed to the proportions shown in Fig 3. Use a ‘broken in’ 150mm No 4 double cut file for this, or similar. Small screwdrivers may be sharpened on an India stone lubricated with clock oil.

MAKING OILERS

Oilers can be purchased already well shaped and in different sizes, but inevitably they are eventually damaged. The following notes on making an oiler can also be used for repairing a damaged one:

1. Select a piece of ‘blue steel’ 50mm (2in) long and a diameter to suit the size of oiler being made. Alternatively, select a sewing needle and temper the pointed end to a light blue for one third of its length.

2. File the steel to a gentle taper, then rest the filed end on a hardened rounded surface, for example the handle of a pair of top cutters, and flatten the end with a light hammer.

3. Stone the two flats so that they are uniform then stone the sides to the required shape. Stoning across the face of the oiler gives greater control over the way the oil leaves the oiler.

4. Make a handle from an old plastic knitting needle, using techniques adapted from the section on repivoting. When the blade is inserted, the oiler is ready for use.

Fig5Thefinishedoiler.

3

CLEANING A SIMPLE CLOCK MOVEMENT

A ‘timepiece’ is the usual name given to a clock without strike or chime or alarm. A timepiece is likely to have two plates, one train (a time train), an escapement and motion work. There will be a ratchet arrangement to hold a mainspring or weight in a wound state, and a clutch arrangement to turn the hands independently. A pendulum or balance may be used to control the speed of the running down of the train.

There is a wide choice of clock for our first practice, but a Smiths eight-day timepiece has been chosen for three reasons: such clocks are still around in reasonably large numbers and might be acquired through car boot sales quite cheaply; they are representative of many other clocks, and so principles can be grasped and transferred; and finally, they are simple.

The first thing to do when tackling a repair is to establish why a clock has stopped. Often the reason is simply that the old oil has dried and congealed, causing a drag on the train and escapement. This condition is easily recognized by looking at the countersinks around the pivot holes and observing the old, dried, congealed oil. The condition is often accompanied by a more generally dirty-looking movement, particularly around the pinion leaves and the other working surfaces.

Pivot holes may be worn, causing inefficient transmission of power. Gripping the great wheel between index finger and thumb and reversing the normal direction of drive of the train usually shows this up by causing pivots to jump across worn holes. Worn holes often appear with what looks like black, congealed oil.

Steel pivots may be cut because foreign bodies are embedded in the pores of brass pivot holes; this condition is often associated with red dust around the pivot and hole. It can be dealt with in a number of ways (these will be looked at later).

Attempting to wind the clock will show up a broken mainspring. If no power can be felt at all during windings probably the mainspring is broken at, or near its inner end. When some power can be felt during winding but the mainspring can be wound indefinitely, probably the spring is broken at, or near its outer end.

Repairs will be covered in subsequent chapters; for the moment we shall concentrate on dismantling, cleaning, reassembling and oiling our simple eight-day timepiece, and the principles explained here are likely to hold true for any mechanical spring-driven clock. The detail will need to be modified if a different clock is being tackled.

DISMANTLING

1. First, remove the pendulum, which simply lifts off.

2. Remove the clock hands. There are two common ways of securing clock hands, and these are shown in Figs 9 (a) and (b). In the first, the tapered securing pin is removed using flat-nose pliers: rest one side of the pliers against the thinner end of the pin, and the other side against the centre wheel arbor; then squeeze. Assuming the pin loosens, change the grip to the thicker end of the taper pin, and pull it out. There should be a washer which will lift off, then the minute hand should be eased off. The hour hand can now be removed by holding the boss in the centre between thumb and index finger, twisting slightly and pulling.

Fig9Twocommonwaysofsecuringclockhands:(a)ispinned;(b)isscrewed.

In the second way, as illustrated in Fig 9b, unscrew the finger nut with thumb and index finger, and lift the hands off.

3. Remove the movement from the case. This is usually a simple task involving unscrewing six or eight wood screws which are accessible through the case back. Lift out the movement.

Fig10Thesuspensionspringofatypicalmass-producedclock.

The pendulum and the pendulum rod are suspended by the suspension spring; in this type of clock the latter is usually a flexible piece of spring with brass cheeks top and bottom.

4. Remove the suspension spring and suspension rod; these are removed first because the suspension spring is vulnerable. Draw out the securing pin from the pallet cock and pull the suspension spring downwards slightly to clear the cock. Turn the suspension rod through 90° and lift it off the crutch.

5. Next the power must be removed from the mainspring: it is essential to do this before stripping any clock. The operation has to be carried out with great care to avoid damaging the ratchet wheel teeth and to avoid getting a nasty clout from the winding key. In the absence of a letting-down key, use the clock winding key to let the mainspring down.

Letting the Mainspring Down

(a) Hold the clock on your lap, and fit the winding key on the winding square. (b) Wind the ratchet wheel by half a tooth, then with a piece of pegwood, disengage the click by pressing on its tail. The click needs to clear the ratchet wheel, but by verylittle if damage to the click spring is to be avoided. Holding the click in this position, let the mainspring down by half a turn, then release the click and wind by one tooth. Check that the click is fully engaged. (c) Without releasing your grip on the key, lift it off the winding square; then with a twist of the wrist, reposition it on the winding square again and repeat the operation.

Keep this up until all the power is removed from the mainspring; and when you feel you have reached this point, check by feeling that the great wheel is free. It must be sufficiently free of power to be rocked easily in a clockwise and anti-clockwise direction within the limits allowed by a tooth in between two leaves of the intermediate wheel pinion.

Every clock repairer has experienced a knock from an uncontrolled key but strict adherence to the above will minimize the risk. A letting-down key has no wings and is smooth so it can be allowed to turn under control in the palm of the hand while the click is held clear of the ratchet wheel (Fig 11).

Fig11Lettingthepoweroff.

6. Remove the two screws holding the pallet cock, the pallet cock itself and then the pallets. There may be washers under the pallet-cock screws.

7. Remove the minute-wheel retaining clip (often a straight taper pin or a wrap-around pin), the washer, the hour wheel and the minute wheel.

8. Unscrew the bridge holding the ratchet wheel and remove the ratchet wheel. The click and click spring may be riveted to the plate (as they are here), or they may be screwed. Remove the screws as well.

Fig12Removingthecannonpinion.

There are three common methods of holding the plates of clocks together, and in each instance the pillars, usually four, may be riveted into the other plate. Both top and bottom plates may be fastened in the same manner.

Fig13Threewaysofsecuringclockplates.

9. Remove the more convenient plate by first unscrewing the four pillar nuts. If the front plate has brackets to secure the movement to the case, try not to move these; instead remove the back plate, carefully avoiding bending any pivots. To help achieve this, lift the plate vertically, keeping the plates parallel.

10. Remove the intermediate wheel, the fourth wheel in the train and the escape wheel by lifting them vertically from the plate to avoid bending a pivot. Often the barrel housing the mainspring can also be removed at this stage, but the centre wheel cannot be removed without first removing the cannon pinion. (It may be that the barrel cannot be removed until the centre wheel has been driven out.)

11. Remove the cannon pinion. Support the plate with a stout watch-brush handle (otherwise an old file covered with paper to protect the plate will suffice), and drive the centre wheel out with a mallet, holding the clock over the bench. An old clock hand placed on the square of the centre wheel will prevent the centre arbor splitting the mallet or getting embedded into the mallet. Make sure the driving blow is straight to avoid bending the arbor, although a slight bend can be straightened later. The barrel will fall out during this operation unless previously removed.

12. The barrel usually has a cut-out in the cover intended to assist cover removal. Mark the wall of the barrel to identify the relationship between the cover and the wall; in quality clocks this is often done by a light countersink in the wall beside the cut-out.

13. Remove the barrel cover by holding the wall of the barrel under the teeth in one hand and striking the end of the barrel arbor with a mallet. Usually this doesn’t dish the cover, but if it does, the dish is easily taken out. Removing the cover by making use of the cut-out provided often damages it, and the method explained is the better way.

Taking Out a Dish in a Barrel Cover

Support the outside edge of the cover on an old barrel, and either press on the centre with a press tool, or use a punch on the centre of the cover; flatten by striking the punch with a mallet or hammer.

14. Remove the barrel arbor by gripping the square with pliers, and turning the arbor in the opposite direction to winding and drawing out slightly. If necessary, lift the inner coil of the mainspring away from the arbor with a thin screwdriver. Hold the barrel in the opposite hand for this.

15. Next, the mainspring should be removed from the barrel, in particular to inspect the outer end to ensure that it isn’t torn. To remove the mainspring, in the absence of a mainspring winder, hold the barrel in a gloved hand and grip the mainspring with long-nose pliers by an inner coil, then carefully lift out just one or two coils to begin with. Gradually ease out the remaining coils under control. This is not an easy task, and you should take care to point the barrel away from your face in case the mainspring comes out suddenly. Often the last coil has to be unhooked from the wall of the barrel. Once the mainspring is out of the barrel, check the end. Look for tears in the steel between the hole (eye) and the mainspring end.

The dismantled clock is now ready for cleaning.

CLOCK CLEANING

Although clock cleaning can be mechanized, cleaning by hand is still widely practised. The process usually involves a cleaning solution, a compatible rinsing solution and some form of drying. The cleaning solution should loosen congealed oil, assisted by a scrubbing action with a stiff bristle brush, while the rinsing solution must dry without leaving deposits on the clock.

Proprietary clock-cleaning and rinsing fluids are available through material houses. Some are toxic, others are non-toxic. There are waterless fluids and concentrates to be diluted with water, there are ammoniated and non-ammoniated cleaning fluids, fluids that will brighten dull brass and fluids for use in an ultrasonic cleaning machine. Which sort is used on clocks will depend on the method of cleaning – whether by hand, by ordinary machine or ultrasonic cleaning machine – and also on which cleaning fluid your supplier stocks, and your willingness to compromise on appearance for the sake of conservation.