Cutting external threads
- 1. Mechanical Engineering Technology External Screw Thread Cutting Objectives: Students should be able to: • Define external screw thread. • State and explain the uses of Dies and the tools used for holding them. • State precautions associated with external screw thread cutting.
- 2. Hand Threading Safety • When using the tap or die use compressed air to clean the piece that you are threading. • Chips from the work can be sharp so use a brush to remove them. • Wash hands after using cutting fluid because it can cause skin disorder. • Be sure that die is securely clamped in the die stock because it can fall and cause painful injuries. • Be careful when handling broken taps because they have sharp edges.
- 3. Cutting External Threads Dies are used to cut external threads by hand. Solid Dies, are not adjustable and for that reason are seldom used. The Adjustable Round Die, are the most widely used die for hand use. The latter has a wide range of adjustments and is fitted with guides to keep it true. Dies are available for cutting most standard Threads.
- 8. EXTERNAL SCREW THREAD CUTTING STEPS 1. Material size must be equal to the outside diameter of the thread. 2. Chamfer the end of the metal. 3. Clamp work securely in bench vice, level and square. 4. Make clockwise turns to start the threads and anti- clockwise turns to break the chip 5. Oil must be used to lubricate the threads.