Page 75 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

1
60 Automobile mechanical and electrical systems

Figure 1.84 Junior hacksaw. (Source: Evan-Amos, Wikipedia)

Figure 1.85 Sawing machine. (Source: Audriusa, Wikipedia)

for attaching a narrow disposable blade. A screw or another mechanism is used
to put the blade under tension. The blade can be mounted with the teeth facing
toward or away from the handle, resulting in cutting action on either the push or
pull stroke. The push stroke is most common.
Blades are available in standardized lengths, usually 10 or 12 inches (15 or
30 cm) for a standard hacksaw. Junior hacksaws are usually half this size ( Fig.
1.84 ). Powered hacksaws may use large blades in a range of sizes ( Fig. 1.85 ).
The pitch of the teeth can vary from eighteen to thirty-two teeth per inch for a
hand hacksaw blade. The blade chosen is based on the thickness of the material
being cut, with a minimum of three teeth in the material. As hacksaw teeth are so
small, they are set in a wave so that the resulting cut is wider than the blade to
prevent jamming. Hacksaw blades are often brittle so care needs to be taken to
prevent fracture.

1.6.6 Thread cutting

Taps and dies are cutting tools used to create screw threads. A tap is used to
cut the female part of the mating pair (e.g. a nut) and a die is used to cut the
male portion (e.g. a screw). Cutting threads using a tap is called tapping, and