Types and purpose of the tool
The die is a tool that is designed for cutting external threads. It has the form of a nut with holes that form the edges of the cutting type. In them is from 3 to 6 holes through which chips are removed. The thickness of the plate is 8-10 turns, the length of the part of the sampling type should be from 2 to 3 turns.
Dies made of alloy steel 9XS or less often made of high-speed steel( P18, P6M5K5, P6M5) are produced. In the choice of die, the main factors are: the purpose of use and the diameter of the part for the thread. Elements are of four types:
- Metric( M) is required for cutting outer metric threads. The pitch is 0.25-6 millimeters, the diameter is 1-72 millimeters;
Note! Dies with a large diameter are only available on special order.
- Pipe cylindrical( G) is used for cutting on cylindrical pipes. The angle of the thread profile is 550. Widely used dies, whose diameter is 1.8-2 inches;
- Pipe conical( R) - the thread running is conical. The density of the connection is achieved by deformation of the turns;
- Inch conical( K) is required for cutting the external thread of a conical type. Diameter is measured in inches. A distinctive feature is the absence of deformation due to a wide profile.
Preparing for operation
The insert cuts into the workpiece by feeding the holder. Then the tool is self-tightening, and the holder moves along the mandrel. At the end of the process, the key enters the annular groove, and the holder is easily rotated. The cartridge should be adjusted to the length of the thread to be cut.
To fix the smaller plates in the mounting hole, the adapter rings are installed. Thread cutting with a die requires some preparatory steps:
- Checking the tailstock( the machine unit to hold the workpiece) and the spindle( rotating shaft of the machine);
- Fastening of a die in a cartridge and its installation in a tailstock quill;
- The tailstock should be installed as close to the workpiece as possible and secured;
- The threaded chuck is adjusted to the required length.
After the preparation is finished, the die is fed manually to the workpiece and 2-3 threads are cut. Subsequent cutting is due to self-tightening. The cutting speed of steel billets is equal to u = 3-4 m / min, for cast iron u = 2-3 m / min, for brass u = 10-15 m / min.
Important! When making threads with dies and taps, it is important to calculate the force applied to the part. It will depend on the thread pitch: the smaller it is, the less effort it takes to apply.
Cutting
Once you have finished preparing the part for thread cutting, you can start working. The die is clamped with screws in the funnel, which are located along its contour. The sharpening machine removes the bevel at an angle of 60º to 80% of the required thread diameter. This is done on the end, on which the cutting will be performed. Next, the plate must be greased with grease or vegetable oil.
Note! Machine oil is not recommended for lubrication, as it spoils the threads.
After lubrication on the rod, clamped in the vice, a horizontal screwdriver with a plate is installed horizontally. The collar rotates with two hands clockwise( if the right thread is made) with a slight pressure on the die. After several scrolls, the die turns back to break the shavings. Such actions are repeated until the required thread is ready.