Cylinder-head, or cylinder-cover. A piece that encloses or seals the end of a cylinder.
D
Dead centre. The stationary centre of a lathe.
Dead-smooth file, or superfine file. The finest or smoothest cut of file.
Delivery-rolls. Rolls that remove the work from a machine or from its cutters or knives.
Describing-circle. The circle or cylinder containing the pencil for rolling a curve.
Diametral pitch. A system of designating the pitches of gear wheels.
Diamond-point. A machinist’s chisel, square in cross-section, having a diamond-shaped face at the end, and two cutting edges, one at a right angle to the other.
Die. 1. A tool for cutting threads upon external surfaces, such as bolts. 2. A chumpy sliding piece.
Differential screw. A screw having a coarse and a fine thread, the difference between the two pitches enabling a more powerful strain to be endured by the thread.