The main and second arbors had to be planted in their proper places, which I've already done. Now I can finish and plant the second arbor which is the intermediate between the two, using the Webster depthing tool.

I made the second arbor from 1/8" music wire, cutting a 1/16" pivot on both ends. The pivots were cut with a graver in a 1/8" collet in the old Webster watchmakers lathe. I put the finish on the pivot surface with an old watchmakers pivot file. One end is a very fine file, and the other is a burnisher. The hard steel of the pivots burnishes very well with this old tool, leaving a polished surface that should wear forever.

I mounted the 60-tooth second wheel on one end of the arbor, using a wheel collet. The wheel is also hollowed with a serpent's tooth bit. Then, I also put 20 needles in the ratchet pinion. All as described in an earlier installment.

The center hole in the ratchet pinion itself is reamed with a "one over" reamer, or .001" over 1/8". This makes it free-turning on the arbor. I also made a small collar which slips over the arbor and retains the ratchet pinion in place. The other end of the maintaining mechanism is held in place by the set screw in the maintaining mechanism's cover.

I determined the location of the second arbor on the clock plates by first mounting the main arbor with its main wheel and the second arbor in the Webster depthing tool. I use sight and feel to adjust the depthing tool so that the gears mesh most smoothly.

Then I put one depthing tool scriber in the 3/16" hole in the front plate for the main arbor and used the scriber on the other side of the depthing tool to make a circular scratch in the paper on the front clock plate. This indicates the proper distance for the location of the second arbor vis-a-vis the main arbor.

Then I repeated the operation, but this time with the second arbor and the center arbor in the depthing tool -- making a circular scratch on the plates which indicates the proper placement of the second arbor vis-a-vis the center arbor. Where these two circular scratches intersect it the place where the second arbor is to be planted. Thus it's properly positioned for a good mesh with both main and center arbors. Once I've located the spot, I can center-punch it and drill the pivot holes in both front and back plates, after pinning them together as described in a previous installment.

The first 3 arbors of the train turn smoothly, and power is easily transmitted from the main arbor to the center arbor. Next, we'll plant the fourth arbor.

Today's links:

Second arbor and pivot file
Ratchet pinion needled
Second arbor done 1
Second arbor done 2
Webster depthing tool
Mainwheel and center arbors depthed
Second and center arbors depthed
Webster scribe marks (pretty faint!)
Three arbors 1
Three arbors 2/
Three arbors 3
Project supervisor