cutting metals

cutting metals

1. shearing and bending

   • tinsnips
     • are used to cut small pieces of sheet metal
   • bench mounted
     • shears provide leverage
   • bending
     • sheet metal can be done in several ways. folding bars are common method, but many schools have bending machines.

2. pressing

   • in industry, presses are used to bend and form sheet metal (pressing),e.g. car body panels and central heating radiators
   • presses are controlled by hydraulic rams, which create massive pressure. sheet metal is stamped and pressed cold.

3. drilling and chiseling

   • cold chisels are made from steel. one end of the chisel is sharp and hard so it can cut material. the other end is soft, so it can withstand the hammer blows.
   • Drill bits are usually made of carbon steel or high speed steel (HSS)
   • twist drills or jobbers drills are used for drilling holes in metal and plastics
   • Larger holes can be cut using a tank cutter

4. screws

   • screw cutting can be carried out on most metals
     • a tapping hole (smaller than the thread) must be drilled in the metal before an internal thread can be cut.

5. thread cutting

   • threads can be cut using a lathe. in industry, many threads are rolled. Hard threaded rollers rotate the material and press it into shape. this is a form of cold forging.