Improvements in Mathematical 'Half-set' Compasses.

摘要

5747. Thompson, W. P., [Boden, E. T.]. March 27. Compasses, drawing.-Relates to the fixing of the insertions or removable points in half-sets of mathematical compasses. The flat piece b, Fig. 1, with the slot g, is fixed between the sides or jaws of the grooved arm a. The flattened ends e of the insertions have grooves f to correspond with the solid part of the strips b, and the groove g correspondingly fits over the solid flattened parts of the removable points. The whole shank of the pen-point may be flat as shown in Fig. 4.