Cheshire Cat's 'Wooden-Wheel' Longcase Clocks
This site gives some details and links to wooden movement clocks that I have made and others that have inspired and interested me in my hobby.
Mechanical clocks have interested me for years, and to make working, accurate and interesting examples is one of my aims in life.
I, like many before me, have had a model making and DIY hobby to add skills and knowledge, required for most of the tasks involved building clocks and cases for clocks. Making a case an putting some sort of electric - ready-made movement in it has little appeal. for me unless the clock is mechanically interesting and being restored from a non-working example.
Placing an old mechanical movement in a new case starts to get nearer the mark, but the real challenge is to make a clock movement from scratch, and to then house it in a suitable case. If the eventual design works and looks good, that is a large part of the journey done, but to really be worth the effort, the clock should be functional, a thing of beauty and accurate.
With a few basic woodworking tools and skills, the easiest and cheapest first step is to make a wooden movement clock. On the face of it it is simple: Using fine-grained flat plywood or other flat close grained hardwood, cut out teeth on wheels with a fret saw. File and sand out the imperfections, then if you are lucky you have a clock which will work when put into a train of wheels on arbours. There are many great web sites for wooden wheeled clocks. I have listed a few favorite links below:
Inspiration for making a clock is out there, and I certainty had a few ideas myself to add to what I found. There are plenty of ornate designs and quite a few plans for purchase. I was impressed that Brain Law not only had fantastic plans and descriptions, but he was happy to publish them for free. I had a friend who had spent quite some time making digital CAM versions for a laser cutter, and this is what my second, third and fourth clock have used in the movements.
Cutting gears by hand is very time consuming and prone to errors. There is a youtube video of someone making gears on a scroll saw which is useful to watch. You will see from the examples shown above and your own experience that there are many good ideas which can be adapted to your own purposes. I was interested in a clock which could show a moon phase, seconds hand, date and keep good time.
My current longcase clock is better than 2 seconds per day, varying slightly with the weather and temperature. Sometimes gaining a second and sometimes losing a second, overall, keeping excellent time. To get that sort of accuracy out of a wooden clock has taken an invar pendulum rod, steel 8-inch x 2-inch bob that is semi-compensated. I say semi, as I have not done the detailed calculations to set up of suspension spring, blocks and crutch. My next pendulum bob is brass and to a fully compensated design so I am hoping for better things. The weight, by the way is near 15kg and the bob 3.6kg.
Using a design by Brain Law, I built a variation of his Clock No.1. I quickly found that the excellent wheel design was hindered by my own ability to create hand cut gear teeth and efficient bearings. The original weight was found to be way too light for my clock and the issue of winding twice a day became an inconvenience. The timekeeping was good when the clock ran, but without long uninterrupted running available, making it any better was going to be a challenge.
The addition of a really seriously heavy clock weight made from a steel water pipe of 2 inch (50mm), filled with lead brought the possibility to run the clock longer by using a long weight line over pulley blocks. I then found the problems with adding an excessive weight to the clock frame was to pull it downwards and so binding the arbors and pinions, resulting in the clock stopping. To alleviate this, I ran a double pulley on the ceiling and a double pulley on the weight. This running uphill did help to even out the forces downwards of all the other parts and was quite successful. The clock then with a run of seven foot six inches ran for just over two days.
Now having large weights needs stronger barrel and bearings. Also, the original winding key way way too small. The ratchet that holds the weight back eventually broke and the weight did a rapid decent to the floor. A serious re design took place with some added functionality.
I wanted a seconds indicator and a strike for the hour, so added an idler wheel above the escapement and a seconds arbor above this. Adding a bell above the whole movement run from a single pin off the hour wheel also worked well, although stopping the clock occasionally due to the increased friction. The seconds indicator was especially important to run freely, as the escape wheel gets very little to run it.
The heavy weight was having an adverse effect on the gear train at the barrel end of the train, so after a disaster where the lower wheel stripped a couple of teeth, I retired the clock for some time. Looking at the bits I thought of doubling up the wheels at the bottom end and to add a much stronger winding mechanism using a square steel pin and a new gear to drive the barrel. I bushed out the pivot holes with aluminum tube and replaced the wheel bearings from wood to aluminum tube also. I was using arrow shaft type material, anodized in and out which was quite hard, and with the addition of a little dry lubricant such as teflon or graphite did improve things, but the real problem was starting to be the clock frame itself. The frame on Clock No. 1. is quite narrow and prone to bending, so a flat ply plate was thought to be the answer. This would mimic more closely a brass longcase movement, and hopefully be far more rigid.
A colleague at work was due to retire shortly, so I planned to make a clock as a gift, using the previous knowledge and design adaptations with a new set of experimental (for me anyway) parts.
The new clock was to have an hour single strike of better design. Brass bell. Brass lens shaped pendulum bob replacing the original wooden disc, and a suspension spring in place of the knife edge from the earlier design. The face would be a true chapter ring and the pendulum rod wooden rather than plain mild steel. The pulleys would be ball raced and all the main arbors ball raced also. The winding barrel to be brass and wood composite design to maximise strength, with a spring click ratchet. The next biggest addition was a moon phase wheel:
Pendulum Bob, Beaten Brass, polished. This was made from sheet brass, cold beaten on a wooden block with a large ball pein hammer, then soldered together. Decided not to fill with lead in this case. The rating nut is a brass cylinder, threaded to suit the steel bar through the centre of the bob. The steel bar is square to stop rotation, and screws into the base of the oak pendulum shaft.
Escape Wheel, second version with wooden bush. Third version is aluminum bush.
Early version of barrel ratchet. (ply wooden spring - this eventually broke under pressure from weight, so was replaced with brass design)
Later version of ratchet springs (dual to give load spread and safety). Made in brass sheet and bar, soldered. Pinned near centre and screwed near edge,
Finished clock face.
The mess of a busy workshop, gluing up the face using whatever to hand to weight down the parts whils the gule dries.
Making the face; gluing up the dial to the base, set in to a routed out base.
Moon Phase Dial (my own design), painted in gloss enamel paints.
Power driving wheels. The centre wheel takes the full 15+ kg of the main weight, so is double width for security.
Sideways view showing part motion work and moon phase drive.
Motion work and moon phase drive.
Winding wheel rear view. Double width wheel, steel arbor, strong frame.
Pin and washer drive to barrel and centre wheel. Piano wire (very hard steel).
Wedge Pegs to hold the clock plates together.
Winding Key, steel and brass. Old door knob and commercial winding key married to a square steel shaft. Pinned with piano wire to key and riveted over. The handle is just screwed and locktighted in.
Weight and pulley arrangement. Brass handmade. Steel 7-strand high tensile wire for weight line.
Pendulum bob; brass and oak, with brass rating nut. Approximate 6 inch / 150mm diam.
Side view of clock showing maintaining power and chime bar.
Suspendsion spring on brass blocks, pinned to oak pendulum shaft.
Weight and pulley.
A description of a basic Invar Pendulum bob. My variation has a steel 2" x 8" bob, drilled out to 6mm. Version 1 has a 1/8" invar rod passing through a brass ferrule at the top and is then passed to a steel 6mm threaded rod for the rating nut. The V1 design is only partly compensated. The Version 2 design uses a 6mmm Invar Rod and compensating brass plug.
Invar Pendulum Design
Detail of date windo. It may be small, but it works!
Dial center and hands. Left winding hole for main weight. RHS hole for balance effect only (unused). A future design will have separate weights for strike mechanism.
Part way building the mouldings from several pieces of oak that were machined on a router table. In all 5 layers each section, then three sides. I am using the heavy planes and scrap to hold it all together whilst the glue dries. It is just too difficult wit clamps.
Hood pillars made in two parts on CNC lathe. Base/Top is square brass soft soldered to brass thick walled tube after machine cutting. Single hole allows screw to pass from pillar side to hood side. Reversed at base for ease of removing.
The later clocks have double ratchets to spread the forces of the weight barrel, and to give a margin of safety. Even so, I place a telephone directory in the bottom of the case (should be a strong sand bag really). Note ball bearing races on two pinions and spacing washers. Steel wire of about 70kg breaking strain.
Spandel details (Meadows and Passmore, large). I will move these out slightly soon as they should be in line with the edge of the dial for the correct look. The brass attachment fixings are soft soldered to the rear of the spandels and then bolt through the wooden face (abou 15mm thick).
Detail of partly lead filled stainless steel weight case shell. Brass 1/4" x 1/2" cross drilled and pinned attachemnt is cast into lead.
Longcase Hood and Dial. Note hatch to observe movement whilst winding. Identical hatch on LHS to engage maintaining power. Hood slides forwards to reveal the movement.
Almost finished! Just final polishing, sealing, final ornamentation, lock and glass.
Longcase Clock without glass fitted.
Mantle Clock Retirement Gift to former work colleague, oak case, laser etched dial, brass fittings, Smiths movement, 2009.
Clock No. 5 (Oak)
Clock No. 6 (Mahogany, Iroko and Oak)
Last updated 20/7/12
By Jonathan Howell