Another tale from the bench of my apprentice days, overhauling a lovely Longcase clock that required replacement seconds and calendar hands. Longcase clocks are my favourite to work on here in our clock workshop in Hampshire.
The movement has already been fully dismantled by my colleague so I inspect the wheels and other parts for any obvious damage. All the pinion leaves and teeth seem to be in good condition with no significant wear.
All pivots are burnished on the lathe and finished by hand using polishing papers.
The brass plates are cleaned briefly in the ultrasonic tank, rinsed and dried using a hairdryer. This is done to get rid of the old oil which will enable me to identify any pivot holes that may need attention.
Both the going and strike trains are replaced in turn to check the newly burnished pivots in each of the pivot holes.
I identify two pivot holes that are in need of bushing due to wear and mark the plates with a drywipe pen so that I can easily identify them.
Cutting broaches are used to widen the hole for a suitable brass bush. The bush is then hammered in so that it is flush with the inside of the plate and the other side is filed down and excess material is removed to create the oil sink using a manual drill and an oil sink cutter to the depth of the existing ones on the plate.
The brass plates are badly corroded from fingerprints and oil so I decide to clean the movement in a Horolene solution which I have found is better for removing tarnishing.
The parts are removed from the Horolene after 15 minutes and a fine wire wool is used to polish up all surfaces before being rinsed
Next a chalk brush is used on the plates to produce a clean shiny finish that the customer will appreciate.
The pivot holes are pegged out to remove any remaining cleaning solution that may cause corrosion if left.
The rack spring has broken at some point and has been soldered rather badly by someone who has worked on the clock previously. I have therefore decided to replace it.
Measurements are taken from the original spring and the teardrop shape is marked out on a piece of brass. A piercing saw is then used to cut out the shape and it is finished off with a file and some fine grade emery paper. A hole is drilled through the centre to match the width of the screw.
Next, some brass wire is shaped and manually hardened by being lightly hammered on a steel block. When the wire is springy and retains its shape a hole is drilled into the bottom of the teardrop and the wire is soft-soldered in place.
I have decided to blue the hands as they have previously been painted black which has chipped over the years and doesn't look very attractive. The black paint has to be removed first which is done by scraping it away with a scalpel blade. The surface of the steel hands is then polished up using some emery paper and a nail buff.
For blueing hands a steel tray filled with brass filings is secured in the vice. This is used in order to carry the heat evenly across the hand and ensure the same colour is achieved along the whole length.
A larger blowtorch is used and a pair of tweezers so that I can lift one end of the hand from the surface if it is changing colour too fast. This often happens on the end with the collet as it is closer to the flame underneath and therefore more exposed to the heat.
The movement is re-assembled, ensuring the strike train is correctly lined up, and oiled with a natural heavy oil for larger movements such as longcase clocks.
The pendulum and weights are replaced on new weight lines and the movement is left to run on a test stand to ensure that it is striking correctly and the time keeping is accurate.
The customer has asked us to replace the subsidiary hands as the two existing are not the originals and do not fit in with the design of the main clock hands.
Based on the design of the minute and hour hands I use a copy of Painted Dial Clocks from 1770-1870 by Brian Loomes to get an idea of what the original subsidiary hands would have looked like.
I settle on a design that matches a longcase clock we have in the shop which has hands of a similar design.
Each hand is drawn out to scale to obtain the correct measurements. This is then marked out onto the steel by scoring the surface so I can see where to cut.
A piercing saw is used to cut as close to the lines as possible in order to minimise the amount of filing to be done. The piercing saw is kept in an upright position to ensure the edges are completely straight.
Once the hand has been cut from the sheet of steel the edges are filed to give a perfect circle and straight edges along the length of the hand. It is finished with some fine grain emery paper.
For the second hand, a brass rod is hollowed in order to create a tube which will fit over the escape wheel arbour. A hole is then drilled into the second hand and is riveted to the brass rod.
The second hand is then cleaned and polished and blued using the steel tray and brass filings.
For the calendar hand a hole is drilled in order for it to be screwed to the calendar wheel. It is then cleaned, polished and blued in the same way.
