Materials

A suitable frame to house rollers, pulleys andmotor. See pictures.

2 lengths of steel shaft 800 to 1000mm each. I used 25mm diameter shaft covered with rubber hose to help increase traction and stop slipping of barrel

4 bearings with housings to fit shaft size

A small electric motor. I used an old washing machine motor

2 pulleys These need to be chosen to give a suitable speed of rotation for the barrel. See Cardew A Pioneer Potter for details In practice this only needs to be approximate as the mill will work over a range of speeds. My pulleys are 50mm on the motor and 300mm on the shaft

A length of heavy duty PVC pipe and two cap ends I used 250mm OD pipe with the large barrel approximately 550mm long and the two smaller barrels 250mm long

Two end frames that allow barrel and caps to be clamped shut and four lengths of threaded rod with nuts to suit. I had an engineering works make these up. They are made from 40mm flat steel.

A quantity of porcelain balls fired as high as possible. Mine are hand shaped and are between 25 and 50mm diameter approximately. A mix of sizes is preferred. Enough balls are needed to three quarters fill the barrel

Construction

My frame is made so the shafts are 550mm from ground level. It also has castor wheels at one end to allow it to be moved easily. The large pulley is on the end of one shaft, making it the drive shaft while the other shaft is a “lazy” shaft.

Make sure your length of PVC pipe has ends that are cut square then glue one cap end on using plumbers PVC glue. Add porcelain balls to about half to three quarters full then add glaze batch or material to be milled. Add water to about 75mm from top. Fit end cap and gently tap into place. Fit steel end rollers and tighten nuts on the threaded rods.

This PVC barrel has done hundreds of hours without showing much wear making it well worth the cost and time to make.

The particle size that can be milled depends on the hardness of the material but generally if it will pass through fly screen it should be suitable.

My large barrel will take a 6kg (dry weight ) batch while the smaller ones a 2 to 3kg batches.

Remember that moving pulleys and electric motors can be dangerous so ensure adequate care is taken when using such equipment.                                                                                                                 Back to Technical Page