An Approximate Method of Cutting Short Circular Cylindrical Arcs with Very Large Radii of Curvature in the Milling Machine

摘要

In the transmission type curved crystal focusing x-rayudspectrograph, a crystalline lamina is imprisoned betweenudthe convex and concave surfaces of two rigid metal platesudcut in the shape of arcs of right circular cylinders of appropriateudradius to impose the correct curvature on theudlamina. Recently I have sought a method of cutting suchudcircular cylindrical arcs of very large radius of curvatureud(say 2 meters) without the delay and expense involved inudthe use of a large vertical boring mill of four meters diameter.udThe method which I describe here might also proveudof use in the production of circular cylindrical arcs of metaludfor lapping cylindrical lenses.