GB241384A - Improvements in and relating to milling machines - Google Patents

Abstract

241,384. Reed, S. A. Oct. 16, 1924. Milling-machines ; milling helical surfaces. - In a milling-machine particularly for shaping the cambered faces of metal air propellers of aluminium alloy a cutter is employed in which the edge cuts across the work and is traversed at right angles to the line of cut, the peripheral speed of the cutter being not less than 30 feet per second and the width not exceeding 3/16". By this means a light supporting structure suffices to hold the work against the cutting pressure. The bench 1 carries a frame 5 which is adjustable on members 3 and which is provided with rails 4 supporting a longitudinally travelling carriage 7. The latter carries a cross-slide provided with an angularly adjustable table 13, supporting an electromotor 15 driving the milling cutter 17. Vertical shafts 19 adjustable in supports 2 carry parallel horizontal shafts 18, 21, which are connected by arms 22, 23, to a bar 27 and templet support 28 respectively. The rough work-blank is secured by screws to the bar 27 and the templet comprises a number of flanged members 31 each having a section equal to the section to be reproduced on the work at the corresponding longitudinal position. The templets are engaged by a jointed guide-bar 32 carried at each joint by spring-pressed bars 35 having contact blocks 37. In operation, the cutter is adjusted so that when the desired depth of cut is reached, a runner 38 engages the guide bar 32. A cut is then taken by a longitudinal traverse of the cutter. The positions of the work and templet are then varied as successive longitudinal cuts are taken until the work is completely formed. For finishing the work, the cutter may be replaced by a steel circular file or by an abrasive wheel.