08/15/00
Today I fastened the barrel cap to the barrel using four 0-80 brass screws. Since there isn't much room when drilling into the edge of 1/8" brass, I did the drilling operation in the Sherline mill, using the Sherline rotary table. This permitted precise placement at every 90 degrees. The threads were tapped after the barrel and cover were removed from the mill, but the barrel was returned to the mill to oversize the holes in the ring to .063" for the 0-80 screws to go through.
So that the cover will always be put on in the same place, I made a key in the cover which fits into a notch in the barrel ring. The notch in the ring was cut with a jeweler's saw, and a corresponding notch was cut into the cover, then a key was soldered into place in the cover and filed to shape. The barrel was returned to the "box" on the old South Bend lathe to be cleaned up after soldering.
After finishing, I mounted the barrel/greatwheel on a piece of 1/4" brass with a surface gauge used as a pointer to check the truth and concentricity of the barrel. The barrel turns true at the teeth with only a few thou of runout. It will work well.
The last thing to do to the barrel/greatwheel will be to make a mainspring hook stud in the ring of the barrel.
Today's links:
Drilling screw hole in barrel.
Barrel key.
Testing truth and concentricity.
Barrel/Greatwheel finished.