Technology and our changing world high Technology

Review questions

1. 
   What is the pritch el hole of toe anvil used for?
   
2. 
   How do you light toe gas forge?
   
3. 
   What are the three major op erations performed in forging?
   
4. 
   List some safety rules for forge work and heat treating.
   
5. 
   Br iefly, wh at is h eat tr eatm en t?
   
6. 
   Describe how to harden a tool.
   

MACHINING
Machining is an important way of shaping metal. Machines or machine-operated tools are used to remove chips from the metal, giving it the desired shapeor surface.
Machining is one of the four major ways of shaping metal. The others are casting, hot forming, and cold forming.
The basic machining processes are drilling, turning, milling, shaping, and grinding. In this unityou will learn aboutturning metal on a lathe.


The Metal Lathe

PARTS OF THE LATHE

Themetai lathe is the most useful and versatile metalworking machine. It can do straight and tapered turning. It also can cut threads, drill, bore, ream, and perform many other operations. The major parts of the lathe are shown in. Simple stated, the lathe consists of a rigid bed, with a fixed headstock on one end and a movable tailstock on the other. The carriage is mounted on thebed. It carries the toolpost and the cutting tool.
Tire headstock houses the headstock spindle, the gears, and the speed­change belts or levers. When you use the lathe< you will fasten your workpiece between the headstock spindle and the tailstock. Then you will choose lhe cutting tool you wish to use, and mount it on the tool post. The spindle will cause the workpiece to relate so that cutting can takeplace.


ACCESSORIES
There are many accessories, or pieces of special equipment, used with the lathe. These are someof the more common ones.

• 
  Cutting tools or bits are small, rectangular pieces of high-speed steel ground for different operations. They are used for straight turning, taper turning, thread cutting, and boring.
  
• 
  Lathe toolholders are straight, left-hand, and right-hand, enabling you to cut atdifferentangles.
  
• 
  Lathe dogs are clamped to stock to hold it in place when turning it between centers of the lathe. One common type is the bent tail.