The escape wheel is already installed on the escape arbor. Now I will make a pinion to drive it, and a small bridge to hold its upper pivot.
The bridge is made from 1/4" brass machined in the Enco mill. It is L-shaped, with a hole made for the upper pivot of the escape arbor and two holes made to screw it to the back plate. I mounted the 1/4" mother brass in the big vice on the table of the Enco mill and milled the L-shape with a 1/2" end mill. The photos show the process.
I determined the location of the pivot hole in the bridge by simply standing the escape arbor upright in its pivot on the balance bridge, and then measuring the distance to the backplate. It turned out to be .4 inch away from the backplate.
The escape arbor pinion has twelve pins, and I made it using procedures described in earlier installments.
The escape wheel arbor was made extra long, and now it must be shortened and a pivot must be cut on its upper end. I determined the location of the pivot, the pinion, as well as the position of the bridge on the back plate by using a compass to draw a circle on the back plate of the clock. This circle is centered on the fourth arbor pivot hole, and is the same diameter as the contrate wheel which drives the escape arbor.
Using the circle, I marked the location of the bridge on the backplate; the location of the pinion on the escape wheel arbor; and the location of the pivot on the escape wheel arbor. I cut the pivot with a graver in the old Moseley watchmakers lathe. I screwed the bridge to the back plate, using a super-glue clamp and transfer punches in a routine now familiar. I used Loctite to secure the escape pinion to its arbor.
I mounted the contrate wheel on a collet which is secured to the arbor with a set screw, rather than using an interference fit or Loctite. Using a set screw permits adjusting the contrate wheel to properly mesh with the escape arbor pinion. It also makes assembly of the clock easier.
Today's links:
Milling the bridge Escape bridge mother brass Escape bridge Contrate wheel circle Pretty escape pinion Escape pinion perspective Escape arbor done Fourth arbor done Fourth arbor done 2 Fourth and escape arbors in place