08/14/00
Today I made the barrel ring for the mainwheel, and the cap which closes it. The barrel ring was made from 2.5" brass tubing, which has a 1/16" wall. The tubing was first cut to rough size on a bandsaw, then mounted on a wooden block screwed to the faceplate of the Unimat. The block was carefully trued to the size of the inside of the barrel ring, with a shoulder left in the rear up against which the ring will ride.
The ring was slipped onto the wooden block, and both ends were trued. Because the truth of one end depends on the truth of the other end which is pressed against the shoulder on the block, the barrel ring was repeatedly slipped off the block, reversed, slipped back on, and trued. After several such sequences, both ends of the ring were true.
Then the ring was soldered into the groove on the greatwheel, using zinc chloride flux and soft solder.
The ring was shortened by slipping the greatwheel into its "box" on the faceplate of the 10" South Bend lathe. A live center in the tailstock pressed against the wheel's center hole to hold it securely in the "box". The edge of the barrel ring was shortened to the correct size, and the inside was trued back about 1/8" with a boring tool. This recess needs to be true, because the barrel cap, with its centered bearing hole, must fit and run true.
Then I made the barrel cap. It is made from 1/8" brass. It is trued on a mandrel between centers in the Unimat. Truing between centers assures that the center hole in the cap is true, and the barrel and wheel will run true. The cap is turned to the inside diameter of the barrel ring, leaving a small shoulder to keep it from slipping into the barrel ring.
Next, I'll bore threaded holes to put screws to hold the barrel cap onto the barrel ring, and will make a key setup, so the barrel cap will always be put back into the same place.
Today's links:
Truing the barrel ring on a block
Barrel ring soldered on greatwheel.
Cutting the barrel cap.
Truing the barrel ring inside.
Greatwheel with barrel.
Greatwheel teeth.