Initial mounting on the lathe
A bowl blank with a flat surface can be mounted on a face plate, a screw chuck, or between centres. A bowl blank with an uneven surface, such as a natural edge bowl can be mounted between centres, on spigot jaws or pin chuck. If the bark is still on the wood, it would be advisable to remove it from the area where the drive centre will locate to avoid the danger of the bark separating from the wood.
The outside of the bowl is shaped first and the spigot or recess for holding in the chuck is also formed. Options for spigots and recesses were shown on the previous page.
Before turning on the lathe
Use appropriate protective equipment, including sturdy footwear and a face shield. For dusty timber, breathing apparatus might also be needed. Set the toolrest at the correct height and when in position, rotate the spindle by hand at least one full revolution to check the toolrest does not hit the wood at any point. Initially set the lathe speed low, especially with out of balance blanks. Increase speed to a safe level progressively and if there are excessive vibrations, stop the lathe, check everything is still tight and start again at a lower speed. For those (like me!) that work in inches, divide the diameter of the bowl in to 6000 to give an indication of the correct turning speed. i.e. a 10 inch bowl would give 600rpm. Note. that this is just a guide, if the lathe vibrates excessively at speeds below the optimum, slow it down or balance the blank by cutting it to a better balanced shape before turning it on the lathe again.
Shaping the outside
Wood should be cut in the direction of the grain wherever possible to minimise tearing. For the outside of side grain bowls, this means cutting from the centre towards the edge. For the outside of end grain bowls, the opposite would apply – cut from the edge to the centre.
Tools used – bowl gouge with a swept back grind or a spindle gouge. WARNING – a spindle roughing gouge should never be used for turning a bowl.
Form the spigot or dovetail recess you intend to mount in the chuck for turning the inside of the bowl, ensuring it is big enough to provide adequate grip in the chuck. Form the outside shape of the bowl progressively. Start to form the curve at the lower edge (where most wood will be removed) and work it back, gradually increasing the area being cut. With large bowls and short toolrests, it might be necessary to work in sections. This will avoid excessive overhang of your tool over the rest.
Final cuts should be very light to improve the surface and attention should be paid to minimising ridges. Shear scraping can be used as a final cut before sanding.
Next – Sanding and shaping the bowl
Back to Bowl Design