CLOCK CLEANING AND REPAIR PART 2

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If you have tried cleaning and oiling your clock as described previously and it still will not run, here is some more information to try.  There can be many problems that will stop the clock so a close inspection may reveal the problem before you disassemble the movement.

Clock must be in beat

This refers to a clock that has a pendulum.  It must have an even tic-toc.  This would be the most important factor in keeping a clock running.  If the tic-toc is uneven, most unskilled persons will wedge up one end of a case or angle a wall clock until it sounds even, but the fact is the pendulum leader (the part you hang the pendulum on) usually has a friction joint on the pallet shaft so that you can move it slightly towards the wedged side of clock.  Place clock on a perfectly flat surface and adjust until clock is in beat.  Clocks like Ansonia, Cuckoo etc. have a thin round rod coming down from the pallet and hooked around the suspension spring and rod.  You need to bend this rod slightly until in beat.

Friction in the movement

When you wind the springs or apply weights to a chain drive movement the power passes across three to four gears increasing the revolutions of each wheel until it reaches the pallet (for time) or the chime strike and fan govener (a govener controls speed of chime)  A pivot is a small steel extension on each end of a revolving gear in the drive train.  It revolves in the side plates that are normally made of brass.  A rough or uneven surface on each pivot will cause friction and loss of power at the working end of each drive tain.  Dry oil and black compounded rubbish in the pivot holes will also cause friction and this cannot be removed unless disassembled.

Bent pivots

As the gears in the drive train move further away from the springs they turn faster so therefore become smaller and lighter in their construction.  The pivots on each end become smaller to reduce friction when they turn in the side plates.  Therefore these pivots are more vunerable to getting bent and this stops the gear or fan from revolving in the hole.  The chime fans suffer the most.

Worn pivots

Sometimes when you take the movement apart the pivot has worn away, tapering from full size outside to almost worn through on the inside.  This is not identified until disassembly.  

Side plates with oval shaped pivot holes

When a clock is not serviced regularly, some pivots will wear the round bearing hole in the brass side plate to an oblong shape.  If this happens one side only, the gear lies at an angle and eventually locks up in the drive train.  If you cannot work out which end of the oblong hole is the original position, apply pressure to drive train spring with your fingers in the direction it should turn and the gear in question will be pushed away from its correct location.  Mark correct location with texture pen with an arrow for repairing when apart.

Taking the movement apart

If this is the first time you have attempted to take a movement apart, the more you understand prior to disassembly, the easier it will be to assemble.  Most clock repairers write notes, draw sketches etc. to help assembly.  If you have a digital camera take several close-up photos around movement to refer back to.  Try to avoid the Ansonia - Session movements as your first attempt because they have most of the levers, warning arms and gong strike between the plates and it is difficult to get every part in its correct location until you have some experience.  Always release all tension on all springs as first priority.  If the springs are not in barrels and are open like Ansonia, they must be held in a restricted condition.  There are metal mainspring clamps available to go round the spring when you let it down, which restrict it to around 50mm dia.  (I may have them in my eBay store later this year)  Tie wire can be used or the electrical large black cable ties are OK.  With more modern movements it is best to remove as many levers, rack, snail etc. from outside of plates before parting.  Sometimes the spring barrels will come out as well.  Sit the movement on top of a plastic container like a margarine container.  This allows parts protruding down from the movement to sit in the container.  With the nuts facing to the top side, undo and remove each nut and carefully lift off top plate leaving most gears standing in bottom plate.  If you have a small cardboard box turn it upside down and when you remove a gear from bottom plate, push it into the cardboard box in a similar location.  This will aid assembly.  I usually clean the parts in the following solution. You will require a plastic container with a lid.  I have a black rectangular plastic container with lid.  This keeps the light from destroying the strength of the solution. You will require 2 -3 litres of cloudy amonia, same quantity of mineralised or distilled water, 100 - 200ml of concentrated dishwashing liquid.  I have a small open mesh plastic container that I place all gears and side plates into and immerse in the solution soaking for 2 - 3 hours and maybe overnight if really dirty.  This will make brass parts clean and shiny again.  It may dissolve the varnish coating on the side plates but this does not matter.  Do not leave parts in for days, as it has been known to eat certain metals away.  Hose down after removing, dry the parts and if you have a brass wire brush, brush down all parts to remove loose material.  Clean holes in side plates with toothpicks or paddle sticks cut to a taper.  Twirl in each hole until stick is clean and no more black is coming out of bearing holes.  It pays to clean holes from both sides.  Also clean outside oilwell around each hole.

Repairing oval shaped holes in side plates

The normal repair is opening up the oval shaped hole with a tapered cutter, finding a replacement bushing with a hole the same size as pivot size and pushing it into tapered hole.  The tools for this operation are expensive and you would need to keep a large range of Bergeon bushes to choose from.  For one or two repairs you may ask your local clock repairer to accomodate.  When bushing is installed it usually requires reaming to size so pivot will turn freely without being sloppy.  The reamers used are called cutting broaches.

Bent pivots

Carefully straighten pivot with pliers that have no teeth or serrations on inside of jaws or they will leave grooves along the pivot surface which cannot be removed.  Bend very slowly to avoid breaking off.  Spin gear in drill chuck to check trueness of pivot

Broken or tapered pivots

This requires removing pivot by cutting it off end of gear, drilling accrurately end of shaft, replacing pivot by tapering suitable pivot material, applying loctite and pushing into hole.  Then spin in lathe and machine pivot to original size and polish.  This process requires small lathe, carbon drills etc. - another job for the clock repairer?

Reducing friction on pivots

If you were to view the surface of a pivot under high magnification, you would see small chunks of metal standing up from the surface.  When you polish or burnish the surface you are evening the surface to lower the friction.  Usual method of polishing is to spin gear in a lathe at 200 - 300 rpm and using say 600 grit wet and dry paper stuck to timber surface.  Rub backwards and forwards using oil as lubricant.  When smooth I use a dremmel tool with around 25mm dia. felt buff, applying buffing compound and while pivot is turning in lathe run the dremmel at around 2500 rpm to polish the piviot to a shiny finish.

Assembly

This is a reversal of taking apart.  Place all gears through the bottom plate and check for correct position.  Drop top plate over and starting spring end or bottom of movement, line up pivots with holes and allow them to go through.  Get the two bottom nuts just started and work up the plate aligning more pivots.  At a certain point you should be able to get all nuts started.  Use a flat screwdriver to align pivot with each hole.  Do not apply too much pressure to the plate or you can bend pivots before you have completed assembly.  You may need to lift movement up to eye level to see position of pivot holes but always keep movement level.  It is a tedius job but care and patience at this stage will pay off.  When together and nuts tightened, see if gears will spin freely.  Sometimes you can leave the pallet out and make sure everthing spins easily.  Then spread the plates by easing off the top nuts and installing pallet.  When together add all the outside levers etc.  NOTE   A chiming clock has a position usually one to three minutes before it chimes where it sets itself for the next chime.  That is, it comes off the stop from the previous chime and allowing the fan to spin several times, the gear next to it is locked in position with the small pin in the side of it.  This is called "the warning position"  When the precise time is reached a cam on the mainshaft drops a lever and allows the gear to spin causing the clock to chime.  A common lift for gong strike clocks is a star wheel lifting the gong hammer.  There must be free movement before the gong starts to lift so that the gears and fan can get up to speed before applying lifting pressure.  Therefore the gear and fan should stop instantly after last chime to give you this start up time .  Some star wheels have a friction fit to its main shaft so there is occasions where you can carefully turn star wheel with screwdriver.  Use extreme care not to cause damage.  Now you need to oil clock as described in previous write up.  Grease is used on parts where oil would run off.  For instance the star shaped gong lift should be greased on each point and all lifts on Westminster chime rods.  Most chime rods have somewhere, an anti bounce end and you need to grease these as well.  Correct position for Westminster chime barrel is at quarter past or last four notes at quarter to.  The chime will go down the scale. 

If you have any requests for repair tools please contact me as I am importing from America frequently.  They are expensive but I can give you a quote.  Some of the cheaper parts may apppear in my eBay store later in the year.    

 

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