Turning Stone

Post on 17-Jan-2015

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SkillsTech Australia stonemasonry apprentice turns a sandstone baluster.

Transcript of Turning Stone

Nelson turns a single bellied baluster from a sandstone billet. His first step is to design the baluster, draw it full scale and then cut a template. Next, he makes the billet round, and marks where the design changes direction.

The turning tools are tungsten carbide lathe tips brazed onto lengths of flat steel.

Nelson holds the turning tool held on a tool rest with his left hand guiding the tip against the stone. His right hand holds the other end of the tool.

Holding the tool like this allows smooth and accurate stone removal.

The stone is removed with a scraping action. Dust and small chips fall to the floor and are regularly removed.

The headstock is a steel plate with an 18mm diameter central pin. The four 10mm diameter drive pins penetrate the stone to a depth of 30mm.

The tool rest is 50 x 75 mm steel angle clamped to support brackets. It is easy to shift it in and out to suit the piece’s changing diameter.

The tail stock has a central pin similar to the head stock. These pins penetrate the stone to a depth of 100mm.

The tail stock is advanced and retired with a hand screw.

There are four speed available on a reducing pulley system.The rotational speed is selected inversely proportional to the piece’s diameter.

This baluster is turning at about 50 RPM.

Nelson marks the diameters against the template .

When the position of the diameters are found, the piece is rotated against the pencil to create a line. This guides the tool in removing stone to the correct size in these zones.

Nelson uses the lathe tool to remove stone accurately.

The sizes are checked against the template with a pair of calipers.

Nelson constantly checks the piece against the template for accuracy. When the sizes are correct, the piece is smoothed and finished.

The ends are cut to size after the baluster is removed from the lathe.