I had hoped to be able to mount the frame on the wall today, temporarily assemble the clock and then see if it would run. That didn’t happen as a lot of small jobs had to be done first and it wound up taking a lot more time than planned. At the end of my last blog I was here with the clock temporarily assembled.
One problem solved
You might be able to see in the photo that the main hour dial is too high to match up with the pinion gear of the uppermost wheel on the left. I found out that I had used 10mm ply for the hub on the winding wheel, which is just below the main dial and mounted on the same arbor. I was able to just chisel of some layers of the hub to bring it down to 6.5mm and that in turn lowered the main dial to solve the problem. see below
The Pendulum: The parts were all made and so it was just to finish sand the edges of the pendulum bob. The pendulum bob has a frame that is 12mm (1/2”) thick ply and is capped on both sides with 3mm (1/8”) thick ply. One side is glued up and filled with lead weight and then the other side is glued on to form a sealed box which is pretty heavy. Here is a photo that shows the slot the adjustable pendulum rod fits into and all the side pockets which were filled with lead weight. You can see the bob’s components which are the 3 largest cutouts. see below
The pendulum rod which has a length of threaded rod screwed into the bottom end is pushed into a slot at the top of the bob and pushed through a hole at the bottom of the bob and a nut is screwed on. This makes the length of the pendulum adjustable by making it possible to raise or lower the bob to suit the clock. I understand that all wooden geared clocks are slightly different so some adjustment is usually necessary.
The eye at the top of the pendulum rides on a plywood bearing mounted on the main frame which allows it to rock back and forth causing the pallet to lock and unlock the escapement wheel which regulates the clock’s speed.
The main weight and the counter-weight/handle
The main weight is what drives the clock. It is held by a cord which is threaded onto the winding wheel. The other end of the cord has a handle attached. As the main weight sinks to the floor, the handle (counter-weight) rises the same amount. To rewind the clock after the main weight has sunk to it’s lowest point, the handle is pulled to raise the main weight back up to it’s highest position. This seems easier to me than having to wind the clock with a key. This clock needs rewinding every 24 hours.
I had to turn some end caps for the weights. These end caps are rather clever (by the clock designer, not me). I will explain how they work in my next blog which will cover the full clock assembly and testing to see if it works. The design called for the main weight being a plastic tube filled with lead and with plywood plugs at each end. I copied the functional part, but did my own thing appearance wise.
Since the the weights were 12 sided made from 12mm (1/2”) ply I had to round the insides with my Dremel to accept the round ends.
A lot of repetition here (we call it regurgitation here in Norway), so maybe not too interesting to everyone, but I thought it would help those wanting to build a clock to get a little more familiar with some of the generic features.
I have finally figured out how the clock basically works, that is, how the power is transmitted through the drive train from start to finish. I will share that with you in the next blog. I am still shaky on the size and no. of teeth on the wheels and pinions although I have read a little bit about it.
I’m pretty sure I will get the clock temporarily mounted on the wall and hopefully running tomorrow (unless my wife has other ideas). If I can get everything going well I plan to gift this clock to one of my sons and build another for my other son before Christmas.
Thanks for reading. If the clock runs tomorrow that will be the last chapter of this blog.
-- Mike, an American living in Norway.