Hollow Ball Project

As Yaakov asked about the process here is a quick photo story of the hollow ball process…

I started with a 65mm*65mm*130mm square…

Using a spindle roughing gouge, rough down to a clean cylinder…

Turn a spigot on both ends to suit your scroll chuck. Part through at the center point, but not all the way through for safety. Remount in the chuck on the spigot…

Part off fully and put the loosed piece to one side…now measure the diameter of the cylinder…

Now you need to make an inside and outside template for the ball based on this dimension…the measurement here was 60mm so a circle 60mm diameter was scribed on piece of thin MDF, and allowing for a 2mm wall thickness, a second line scribed inside at 56mm…the kerf on the bandsaw blade I used was 2mm which allowed me to simply cut between the two lines and produce two templates in one cut. The outer template was cut in half to make using it easier in tight corners…

Now use the flat edge of the inside template to mark the cut line for the inside shape of the ball…

Now using a 3/8″ spindle gouge hollow out the half ball to exactly match the template…

Now turn the outside to match the inside, allowing a 2mm wall thickness…leave a stub to support the half ball…

Remove from lathe and re-mount the other half and repeat the process. Once part 2 is complete, aplpy glue to one edge…I used fast cure white glue…and using the center mark left from the roughing out stage bring the tailstock up and lightly clamp the two half balls together. If you are going to leave the ball plain match the grain carefully…

Allow glue to cure, and then using a 3/8″ spindle gouge true the ball using the outside template as your guide…

The template will tell you where you need to cut away wood…here the shoulders are heavy…

And here they are removed…continue turning, cutting into the tight corners and following the template until the stubs are as small as you dare make them…

Now remove from the lathe by cutting through the stubs with a pull saw…then using two cup chucks turned from scrap stock (ensuring the ball doesn’t “bottom” in the hollows) re-mount between centers…

You can see one of the stubs at the bottom of the picture…remove these using a freshly sharpened spindle gouge and very light cuts…the lathe is at low speed here and the tailstock pressure is light to avoid crushing the ball…

Now you can abrade the ball to whatever grade you require, stopping the lathe, loosening the tailstock and re-positioning the ball many times to ensure a spherical result…

I have been turning these for a specific project, but you will have ideas of your own, but at this stage I pyrograph the ball…

And then pierce using a cone-shaped burr to give holes of different diameters…

To and end result like this…

 They are then coloured using a range of stains and acrylics…

Here are a few almost completed balls after lacquer has been applied…and a taster of an almost complete piece using the balls…

And that’s it. I hope you try these as they are fun to make and will help develop cutting skills.

There are other ways of producing these balls, and I don’t claim this is the best…it’s just the way I make them.

Enjoy

Andy

3 thoughts on “Hollow Ball Project

  1. That is GREAT! Thanks so very much for posting this! I can’t wait to try it.

    Thanks again for posting this!

    be well,

    yaakov…..

  2. Also very interesting how to create a hollow ball, and shows lots of time and accuracy. Very interested to see how long it too you to turn the ball.

    Steve

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