Turning

Subject:
Some aids and cheats *PIC*

John K Jordan
One useful aid is to make a ring maybe 1/2 the diameter, and flattened on one end. A piece of PVC or brass pipe works. Mark StLeger demonstrated this in VA and used a 1" ID ring with a bevel cut on the outside. He was turning 2" spheres.

Turn the sphere but don't get carrled away. Hold the ring against the wood and see if it fits tight all the way around or if there is a high place. Turn away the high place, again, without getting carried away. Repeat.

There is a cheat that works too. Instead of using a ring to gauge, use the ring to turn. Some have used a hole saw with the teeth ground off, held against the spinning work, moving back and forth to remove wood only in the high spots. You can start with a pretty crude shape and end up with a perfect sphere.

Long ago I used a piece of steel pipe to turn a bunch of small spheres. It was very quick. I prepared the pipe edge without a sharp bevel, used like a scraper instead of a cutter. The diameter must be smaller than the sphere diameter. Sanding was required to finish.

I have also used the template method.

Another way I've read about is the shadow method - use a bright point-source light directly and high above work. Draw a circle on a piece of white cardboard below the lathe. Turn the wood until the shadow matches the drawing.

Another method is to draw lines on the cylinder first, spaced with a special handy dandy caliper that costs money or with a bit of trig. The lines represent the radial points of an octogon when viewed from the side or top. Cut flats between the lines to make 45-deg bevels. Mark again and cut flats again to form a 16-sided figure. Round over the "points" to get a wonderful sphere. I made one this way after doing the math and it was easy.

Another way is to buy a sphere jig. Expensive and time consuming to set up but you get perfect spheres every time, no skill required. Should work on spindles as you showed with hand turning to get into the grooves on either side. I have the Vermec, ordered directly from Australia (cheaper than buying from the distributor with a favorable exchange rate).

Another way is to turn everything but the sphere then send the spindle to John Lucas to finish up. I personally can't afford this.

JKJ

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