Fig. 274. Fig. 275. Fig. 276.
Steel Frame Breast Drills.
Steel Frame Breast Drill.—These drills are made with both single and double speed, each speed having three varieties of jaws. The single speed is very high, the ratio being 4½ to 1, which makes it desirable to use for small drills, or for use in wood.
A level is firmly set in the frames of these tools to assist the user to maintain a horizontal position in boring. Each of the forms shown has a ball thrust bearing between the pinion and frame. The breast plate may be adjusted to suit and is locked by a set screw. The spindle is kept from turning while changing drills, by means of the latch mounted on the frame, and readily engaging with the pinion. The crank is pierced in three places so that the handle can be set for three different sweeps, depending on the character of the work.
Figure 274 has a three jaw chuck, and has only single speed. Figure 275 has an interlocking jaw, and is provided with double speed gearing. Figure 276 has a universal jaw, and double speed.
Planes.—The most serviceable planes are made in iron, and it might be well to show a few of the most important, to bring out the manner employed to make the adjustments of the bits.
In order to familiarize the boy with the different terms used in a plane, examine Figure 277. The parts are designated as follows: 1A is the double plane iron; 1 single plane iron; 2 plane iron cap; 3 cap screw; 4 lever cap; 5 lever cap screw; 6 frog complete; 7 Y adjusting lever; 8 adjusting nut; 9 lateral adjusting lever; 11 plane handle; 12 plane knob; 13 handle bolt and nut; 14 knob bolt and nut; 15 plane handle screw; 16 plane bottom; 44 frog pin; 45 frog clamping screw; 46 frog adjusting screw.
Fig. 277. Details of Metal Plane.