Machine Tools and Power Tools: notes

The centre lathe

• Purpose: turns round work against a fixed cutting tool.
• Main parts: headstock with the spindle and chuck, tailstock, saddle and cross slide, bed, and tool post.
• Operations: facing (flattening the end), turning (reducing diameter), parting off (cutting a piece free), drilling, boring and knurling (pressing a grip pattern).
• Three jaw chuck: self centring, for round bar. Four jaw chuck: each jaw moves alone, for square or odd shapes.

Drilling

• Twist drill: has a point angle of 118 degrees for general metals.
• Speed rule: a small drill runs fast; a large drill runs slowly. Hard metals need slower speed than soft ones.
• Clamping: clamp the work in a machine vice. Never hold it by hand.

Other machines

• Shaper: a single point tool moves back and forth to cut flat surfaces.
• Milling machine: a rotating cutter removes metal from work that moves under it.
• Pedestal grinder: sharpens tools. Keep the tool rest within 3 mm of the wheel and wear goggles.
• Power hacksaw: cuts bar stock automatically.

Coolant

• Cutting fluid: cools the tool and the work and gives a better finish.