In the old days, complicated clock parts were cast from brass -- which is outside the scope of a small machine shop. But you can use a rotary table to mill many complicated parts from solid brass. This is the way I made the block from which hangs the balance suspension spring. The block also mounts a device to regulate the clock.

The idea is that a billet of brass can be mounted in a 3-jaw chuck, which is screwed onto the rotary table on the mill. A small cut is made, then the table is rotated 180 degrees, and another cut is made. Then the mill table is advanced and the process is repeated until the part has the correct dimensions. In this case, I advanced the table by about 50 thousandths per pass.

Cross cuts can be made by rotating the table once 90 degrees, then thereafter rotating it again 180 degrees to make each pass. The result is a piece which is completely symmetrical and square.

When cutting is finished, the mill spindle can be centered on the workpiece with a centering tool, and holes can be drilled in the proper places.

If horizontal holes are required, the Taig mill head can be rotated to horizontal and horizontal holes can be drilled.

I centered the mill spindle over the end of one of the arms of the regulator block, using a centering tool. I then drilled a hole to accept a 0-80 set screw. This set screw is used to mount the rod which holds the upper end of the balance suspension spring.

Three drills are needed, one for the 0-80 suspension screw just mentioned, one for making the holes for 2-56 mounting screws in the bottom of the block, and another to make the horizontal holes for the regulator parts. There wasn't enough room under the spindle to mount the normal Taig drill chuck and arbor, so I made special drill extensions for the drills. The drills are mounted in a 1/8" piece of brass, and the 1/8" brass "chuck" is mounted in a 1/8" collet in the Taig spindle.

I mounted the drills in the 1/8" piece of brass by first drilling the hole in the brass one number size under the drill; then I put the drill itself in the lathe and tapered the back end a bit wih a diamond file. This way, you can press-fit the drill into the hole. One hole is drilled a bit undersize from 3/32". It is reamed to final size with a reamer.

Once the block is finished on the mill, the billet of brass is removed from the chuck on the rotary table. I then parted off the block from from the billet on the big lathe.

The block is then clamped upside down in the big vice on the Enco mill-drill and the bottom of it (where the parting tool made the cut) is trued with the Enco mill's fly cutter.

I used fine files to remove machining marks from the block, then I used abrasive sticks to optain the fine-line finish I use on working parts.

Today's links:

Cutting, step 1
Cutting, step 2
Cutting, step 3
Centering spindle
Extended drill
Center drilling
Drilling
Reaming side holes
Block attached to billet
Parting off regulator
Fly cutting block
Regulator block finished
Regulator block drawing, GIF

Downloads:
Regulator block drawing, Deltacad
Regulator block drawing, DXF