Unless a workpiece has a taper machined onto it which perfectly matches the internal taper in the spindle, or has threads which perfectly match the external threads on the spindle (two conditions which rarely exist), an accessory must be used to mount a workpiece to the spindle.
A work-piece may be bolted or screwed to a faceplate, a large, flat disk that mounts to the spindle. In the alternative, faceplate dogs may be used to secure the work to the faceplate.
A soft work-piece (wooden) may be pinched between centres by using a spur drive at the headstock, which bites into the wood and imparts torque to it.A soft dead centre is used in the headstock spindle as the work rotates with the centre. Because the centre is soft it can be trued in place before use.
Traditionally, a hard dead centre is used together with suitable lubricant in the tailstock to support the work-piece. In modern practice the dead centre is frequently replaced by a live centre, as it turns freely with the work-piece – usually on ball bearings – reducing the frictional heat, especially important at high speeds. When clear facing a long length of material it must be supported at both ends. This can be achieved by the use of a travelling or fixed steady. If a steady is not available, the end face being worked on may be supported by a dead (stationary) half centre.
In wood turning, one variation of a live centre is a cup centre, which is a cone of metal surrounded by an annular ring of metal that decreases the chances of the work-piece splitting.
A circular metal plate with even spaced holes around the periphery, mounted to the spindle, is called an “index plate”. It can be used to rotate the spindle to a precise angle, then lock it in place, facilitating repeated auxiliary operations done to the work-piece.
Other accessories, including items such as taper turning attachments, knurling tools, vertical slides, fixed and travelling steadies, etc., increase the versatility of a lathe and the range of work it may perform.