Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 131

The patent twisted bits having a screw centre (they are known as screw bits) are first-class, the only thing against them being the expense; they bore well in any wood and in any direction, relieving themselves of the chips and cutting true to dimension. Most of the patents have now expired, and there is not much to choose between any of the following: Gedge’s Fig. 380; Scotch pattern, Fig. 381; Jennings’, Fig. 382; single twist, Fig. 383; and solid nose, Fig. 384. Gedge’s and Jenning’ are particularly good.

Fig. 380.—Gedge’s Twist Screw Bit.

Fig. 381.—Scotch Twist Screw Bit.

Fig. 382.—Jennings’ Twist Screw Bit.

Fig. 383.—Single Twist Screw Bit.

Fig. 384.—Solid Nose Screw Bit.

Fig. 385.—Centre Bit with Pin.

Fig. 386.—Centre Bit with Screw.