Due to a drafting blunder, I found I had to redesign the regulator. There was a conflict between the regulator and one of the arbors, which I didn't foresee.
The redesigned regulator uses the same idea -- that of a moveable foot with a fine slit, which would slide up and down the torsion balance spring to effectively change its length. I retained the idea, but the foot is now set sideways between the plates of the clock, and it's mounted in a new post and block arrangement.
I drilled holes in both the block which will become the new foot and the block that it mounts on at the same time. This makes sure that the holes are exactly in line with each other, so that the foot can slide freely.
I began by using a Super glue clamp to glue the piece which will become the foot to the mother material that will become the mounting block, both being 1/4" brass. I clamped the mother brass in the big vice on the bed of the Enco mill, and used an edge-finder to locate the edge of the brass.
Then I then used the the mill's hand wheel graduation to exactly center the mill spindle over the center of the 1/4" brass. Next I drilled the two holes through both foot and block pieces at the same time. The sizes and spacing of the holes are the same as those in the discarded regulator pieces. Again, I used the graduations on the mill's hand wheels to set the spacing between the holes.
Then I separated the foot and block pieces and sawed the block out of the mother material. There is another hole in the regulator block which serves to mount the 3/32" brass collet which holds the upper end of the suspension spring, which is held in place with a 0-80 set screw, as in the discarded regulator block. There is also another hole made in the block which I'll use to fasten it to the post which supports it.
The foot is drilled and slit, as was described when making the discarded foot. The slit is about .004" wide, which gives a clearance of about .001" on either side of the suspension spring, which makes the foot glide easily up and down on the suspension spring.
The post which mounts the foot to the clock's front plate is made from 5/8" brass. I chucked the brass in the Taig lathe to make the shape, then transferred it to the Taig mill where I made two mounting holes in the base of the post for mounting it to the front plate. I made a spigot on the other end which will fit into the hole in the regulator block to mount it. The block is held to the post with Loctite.
I will eventually cut threads on one of the rods holding the foot. These threads will hold a knob which will screw the foot up and down to regulate the clock. I used a stopwatch to temporarily set the foot, and was able to adjust it to run close to the goal of 4 RPM, showing that the regulator in its present form is workable.
Using edge finder Regulator Block Drilling regulator post Regulator parts Block and foot Regulator parts finished Regulator installed I Regulator installed II Regulator installed III Block and foot, GIF drawing