Chapter 8: Depthing the TrainJune 22, 2005
This chapter covers making the rest of the train arbors, and planting them in the plates. It also includes making a cutter for the escape wheel teeth, and then using it to make the escape wheel. I've been lazy lately, and not taken as many pictures, but here are shots of the completed arbors with wheels and lantern pinions mounted on them:
The pinions and wheel collets are attached to the arbors with Loctite, which seems to hold very well. Actually, my biggest worry in that regard is how to get them *off* again later if I decide they need adjustment. I can heat the wheel collets with a torch, but the pinion pins are held with loctite as well and I'd like to have the option of removing the pinions without disturbing the pins.
The escape wheel cutter is pretty much the same as the ratchet wheel cutter I made earlier, except the diagonal edge is round instead of straight, and ground to a particular radius. The cutter worked like a charm, except for two small stupid problems: first, I didn't leave enough clearance between the large and small end of the super-glue arbor I made for it, so in addition to cutting the teeth on the escape wheel, I cut nifty gouges all around the back of the larger end of my arbor. No big deal, really. Second, I didn't even leave enough clearance for the jaws in my three jaw chuck, and I hit one of them with my escape wheel cutter. So, I had to immediately re-sharpen the cutter, and skip the three teeth that lined up with my chuck jaws. Then, when finished, I rotated the arbor in the chuck, used the cutter to align the teeth properly, and went back and cut the remaining three teeth. It actually appears to have worked out quite well, and the finish on the teeth is wonderful - you can actually see reflections of the other teeth! The other good news is that I have found a better configuration of the vertical milling column than I was using previously. My new configuration differs from how Bill Smith sets it up in his video and keeps the weight of the milling spindle & motor mostly centered over the lathe bed. Because of the reduced torque on the lathe, the carriage moves easily and it's not necessary to support the mill's weight manually when cutting the teeth. A definite improvement.
The final work for this chapter was to drill the pivot holes for the arbors, broach them to size, and assemble everything. Without the escapement complete, the train runs freely. But this was my first chance to see how the gears fit together in the actual clock, so it was pretty exciting. Sadly, I was a little disappointed - there's a bit of a rattle as they turn, as if the depthing is not quite correct, and it takes more force than I'd expected to even get the barrel arbor to start turning. However, the book says that when you quit turning the barrel arbor, the gears should continue spinning and slowly come to a halt. My gears do this (although they halt a little quicker than I'd like) so maybe they will be just fine. I imagine one reason for using the large gear teeth (.8 module) is that the depthing doesn't need to be as accurate. In any case, I was glad to see that at least the teeth didn't bind. I'm still maintaining my optimistic hope that the clock will run once the escapement and pendulum are finished. Here are shots of the plates with the entire train installed: