Brian Law’s Clock No. 24

Brian Law’s Clock #24 is a wonderfully designed wooden clock with a gravity escapement that is fascinating to watch. This was my most challenging clock to build as of May 2016 because it required metal machining and CNC tool path tiling. Tiling was required because the clock frame was longer than the bed of my CNC router table. Fortunately, Vectric’s V-Carve Pro provided a way to accomplish the task.

Mr. Law’s design called for 1/4″ shafts turned to 1/16″ at the ends which are held into the frame using Acetyl bushings. That was his answer to minimizing friction. I used stainless steel and found that it work hardened during the turning process so I limitied my cuts to less than 0.005″ per pass. Despite this tedious process, I managed to ruin one of the parts because the thin shaft bent while turning. I managed to get through it but if I ever make another #24 clock, I will make the shafts using 1/8″ stainless steel held directly in the frame without bushings. The only exception would be the spool weight bearing shaft which I would leave 1/4″ supported by ball bearings.

Tiling First Step

My CNC router table is 26 inches square but the frame was 30″ tall. In order to accomplish this cut, I removed the end support bar from my Pilot Pro CNC giving me a way to pass a long piece through the Y axis. Notice the two indexing holes near the lower left of the work piece and the same hole spacing drilled through near the upper left. These index holes allowed me to accurately position the work piece by using wooden dowels drilled into the spoil board.

Tiling Second Step

Vectric’s V-Carve Pro has a built in tiling feature making the process easy. Well, not exactly easy the first time but now that I’ve done it, it will be easier the next time. Notice that after the first tile was cut, the part was re-indexed by sliding the part along the Y axis.

Frame Parts

The frame front and back pieces successfully cut and ready to be parted from the waste.

Clock Face

In order to conserve material and give the clock face a neat look, I used a CAD program to design an octagon large enough to cut the clock face. This view shows the face after it was V-Carved and nearly cut from the blank.

Clock Parts

Clock parts machined, cut and sanded ready for assembly.

Brian Law's Clock 24

Assembled and ticking on 6 lbs. weight. This clock as designed will run about 15 hours on a wind. Click on the photo to see it in action.