A flat circular plate fitted to a wheel- or pinion-cutting machine, or to a lathe spindle or dividing accessory for a lathe or other machine. On the plate a number of concentric circles are marked, each divided into a different number of equal divisions. Work held on the arbor of the dividing plate can therefore be rotated and divided according to the number of divisions, using a detent located on a selected circle. Alternatively the dividing plate may have teeth on its edge, driven forward by a worm or endless screw, and advanced to the required position by a previously calculated number of rotations of the worm. A useful method of marking out a dividing plate, used by Henry Hindley of York early in the 18th century, is to cut a series of small, equally spaced holes in a long strip of metal, equal in number to the largest number of divisions required on the plate, plus an extra one. The strip is bent to form a complete loop and the two end holes joined by a rivet or peg. A disc of wood is then turned on the lathe until the loop fits tightly around its circumference, which is thus divided into the required number of equal divisions. These divisions can be transferred to a circle on a blank dividing plate and the same strip of metal reduced in stages to produce decreasing numbers of divisions on smaller circles on the dividing plate by the same basic method. The position of the first division of each circle on the dividing plate is usually placed on a radial line, with the numbers of divisions clearly marked for each circle.