The calculations were done in excel to determine the ratios that would give me a good center wheel. IE turn once per hour.
Earlier attempts with a 60 tooth escape wheel taught me just how sensitive such an escape is. This one has 34 teeth and works easier on the depthing wheel.
All the wheels have the same spoke design. The wheels start with a 7 pitch and increase one pitch with each wheel.
The basic wheel sizes are very roughly 7” - 6” - 5” - and 4”.
The full gearing for the clock with all the gears and pinions cut.
Since this is to be a shelf clock a vertical ladder frame seemed OK since it would give enough weight drop for the clock.
The hands will center on the second wheel and the face is actually the pendulum bob and the chapter ring (numbers) are not stationery
The design allows for a double weight which will help use the available height the most efficiently.
The back and front plates are screwed together so that both will be exactly the same when cut. The gears are depthed and the pivots are now drilled through both plates.
The entire running train is placed on the plates and the gear movement ensured to be smooth.
At this point the plates are ready to be separated and the plate spacers can be put in place.
The frames are now separated and bolted together.
Once some finish has been applied the frame is ready for the running train.
With the running train placed on their arbors the 2.5 inches allowed for the gear set is ample.
The Pendulum / Dial is mounted on the escape arbor which means that no crutch is necessary.
I have deviated from my original intention of a 1/4 second pendulum to a 1/2 second pendulum that incorporates the chapter ring.
The finished clock stands 22” tall by 12” wide. With only a 18” weight drop it will be a 12 hour winder. The pendulum only swings about 2” so the although the face moves it is readable
The design of the escape wheel and pallets is shown above. One of the most critical aspects is the distance between centers. Even a fraction of a mm will give problems.
My clock ran but not as good as I wanted. I made a moveable pivot for the pallets. In this way I could make very very small changes in the depthing.
since the “cee” frame sits inside the plates, the outside appearance didn’t change, but the functioning of the clock really did!!
I’ve altered the “cee” to be longer and enlarged the escape wheel to 4” with recoil pallets. To enlarge the angle of swing I placed the pendulum pivot below the pallet pivot.
The result is a much bigger swing that I was after and a rather unique crutch that enters the pendulum rod from the outside. A bid unconventional but it works.
Some major modifications were done on Egypt which included new frame material - more rigid and a new escape from Gearotic Motion
Three arbors and five wheels were necessary to reverse the direction and get the hour hand at one rev. per hour
With that many gears out front in the time train I changed to an Aaron Dodd Crane Daisy wheel time train.
The revised unit looks very similiar but works better.
With an escapement recut I discovered that the clock would run fine on exactly 1/2 the weight so I use the right side (with a reverse) winding to wind the clock. As the drive weight goes down the winde
My objectives in this clock were several: First to build a 1/4 second pendulum with a wide swing so the escape mechanism is designed for a 7º swing instead of the 4º swing common to 1 second pendulum clocks. Second was to build it in the form of a shelf clock. I have a lot of trouble with my clock frames slowly but surely yielding to the driving weight and ultimately causing binding of the arbors. Shelf clocks reduce this tendency since both the front and back plates are equally supported and there is no tendency to distort. The final objective was to arrange a pulley system inside the clock frame so that an acceptable weight fall could be achieved for the clock.
By the time I was finished the objectives were compromised. I changed from the 1/4 second wide swing pendulum for a narrow swinging 1/2 second pendulum so those objectives will have to await a future clock.
Some may wonder where the name “Egypt” came for this clock - Somehow it just seemed right!