GB662297A - Improvements relating to the manufacture of hollow cylindrical glass bodies - Google Patents

Abstract

662,297. Glass. SCORAH, L. V. D. April 27, 1950 [July 8, 1949], No. 18084/49. Class 56 A hollow cylindrical glass body is formed from a tube a, whose internal diameter is less than that required, by causing a drift d, c to be progressively moved through the tube while the tube and drift are relatively rotated and while the tube is locally heated at a position e immediately ahead of the drift. A short length of tubing b of larger diameter than that required is conveniently fused to one end of the tube a and gripped in the chuck of a hollow spindle lathe or like headstock. The drift consists of a rod c of metal, carbon, or other suitable material, and a forward end d shaped so that it presents at least two working edges to the interior of the tube, i.e. of oblong, square, triangular or other section, and of such dimension as to form the required bore in the tube. The part d may be tapered at the forward end. The tube is locally heated, e.g. by a blowpipe to bring it to a plastic condition. Alternatively the tube may be held stationary and the drift rotated, or both may be rotated, and the axial movement may be imparted to the tube instead of or in addition to that of the drift.. The tube may be cut into required lenghts, and may be.treated by an abrasive or polishing action where extreme accuracy is required.