These indexing plates are used in conjunction with both the Axminster 100189 and 200247 rotary tables to enable the table to be rotated by an exact fraction of a complete turn, a particular requirement when machining gears, sprockets, etc. on a vertical mill. There are three indexing plates in the set which together provide all the subdivisions up to 50 (although 28 and 44 carry very small errors). There are a further 26 subdivisions available between 51 and 100 plus others above 100. The spring loaded index pin locates positively in the holes in the index plates and the two brass setting plates help to keep count of the number of holes moved by the pin.