When disassembling and repairing various equipment, it happens to damage the threads on bolts, studs or other prefabricated elements. When installing new equipment, it may also be necessary to use a tool to calibrate existing or cut new external threads. Such a tool exists and has been successfully used for many decades, this is a die. There are many types of it, which makes it possible to cut almost any external thread.
Design and purpose
According to its design, a die is a plate of a certain shape with several holes for chip removal and a cutting edge that forms threaded grooves. The most common dies with 8-10 turns, forming a cone with a small angle of inclination of the guide. The first 2-3 turns are lower to form the intake part.
All threading tools, taps and dies are designed to both calibrate existing threads and form new threads on cylindrical parts. Depending on the type of cutting, use theor another tool. Taps are used for internal threads, and dies for external threads. Previously, non-separable dies were also called lerks, but this name gradually ceased to be used.
Material of production
For threading, you need a tool with increased hardness, capable of processing other metals without its own destruction and wear. For taps and dies, the following steels are most often used in the manufacture:
- alloyed grades KhVSGV and 9XC;
- high-speed steel R5M5; R18 and R6M5K8;
- other carbide grades whose composition is a manufacturer's secret.
Types of plates
The classification of this tool is made according to three main parameters - the type of thread, the shape of the body and the type of construction. The most popular dies for threading the following body types:
- round;
- square;
- hex.
The case itself can be split, sliding or solid. The first two types of housings allow you to adjust the diameter of the thread being cut. Such dies are more often used in production. At home, as a rule, one-piece dies with a constant thread diameter are used.
According to the type of thread, the dies are metric, inch (pipe), conical, right and left.
Application features
Collapsible structures (cut and sliding) have one drawback - they are able to cut threads with a maximum of the second accuracy class. But there is also an advantage - the ability to quickly and easily change the diameter of the thread being cut. For work on lathes, these dies are more convenient.
If it is necessary to obtain a high-precision threaded connection, use solid dies. They also have a drawback: if you need to change the thread diameter, you have to change the die to another one.
Manual threading technology
As mentioned above, a die is a metal-cutting tool that requires proper handling and appropriate preparation of workpieces. The following tips will be helpful for beginner DIYers with little skill in using this tool:
- the workpiece should first be cleaned of rust and dirt with a metal brush;
- the part to be threaded is securely fixed in a vise or other device in a convenient position (preferably vertical);
- the corresponding die is installed in the die holder and fixed with side fixing screws;
- the workpiece is lubricated with a small amount of any machine oil: used oil and even animal fat can be used;
- the die is put on the workpiece, maintaining the perpendicularity of its plane and the longitudinal axis of the workpiece;
- with a little effort press and rotate the tool in the appropriate direction;
- after cutting 5-6 turns, the tool is rotated 1-2 turns in the opposite direction to clean the cutting edges from chips.
The technology for cutting threads with dies on lathes largely depends on the design features of the machine itself and is detailed in the instruction manual for a specific lathe model.
