When disassembling and repairing various equipment, it happens to damage the threads on bolts, studs or other prefabricated elements. When installing new equipment, you may also need a tool for calibrating existing or cutting new external threads. Such a tool exists and has been used successfully for many decades, this is a die. There are many of its types, which makes it possible to cut almost any external thread.
Device and purpose
By its design, a die is a plate of a certain shape with several holes for removing chips and a cutting edge that forms threaded grooves. The most common are dies with 8-10 turns, forming a cone with a small angle of inclination of the guide. The first 2-3 turns are lower for the formation of the intake part.
The entire tool for cutting threads, taps and dies are designed both to calibrate an existing one and to form a new threaded part on cylindrical parts. Depending on the type of cutting, one or another tool is used. Taps are used for internal threads, and dies for external threads. Previously, non-separable dice were also called lerks, but this name gradually ceased to be used.
Production material
For tapping, a tool with increased hardness is required that can process other metals without its own destruction and wear. The following steels are most often used for taps and dies in the manufacture of:
- alloyed grades and 9;
- P5M5 high-speed steels; P18 and P6M5K8;
- other hard alloys, the composition of which is the secret of the manufacturer.
Types of Dice
The classification of this tool is carried out according to three main parameters - the type of thread, the shape of the body and the type of structure. The most popular dies for carving the following types of housing:
The housing itself can be split, sliding or solid. The first two types of housings allow you to adjust the diameter of the cut thread. Such dies are more often used in production. At home, as a rule, solid dies with a constant diameter of the cut thread are used.
According to the type of thread, the dies are metric, inch (pipe), conical, right and left.
Application features
Collapsible constructions (split and sliding) have one drawback - they are capable of cutting a thread to a maximum of the second accuracy class. But there is a merit - the ability to quickly and easily change the diameter of the thread being cut. To work on lathes, these dies are more convenient.
If necessary, to obtain a threaded connection with high accuracy, solid dies are used. They are also not without a drawback: if you need to change the diameter of the thread, you have to change the die to another.
Manual Threading Technology
As mentioned above, a die is a metal cutting tool that requires proper handling and proper preparation of workpieces. The following recommendations will be useful for beginner craftsmen with low skills with this tool:
- the workpiece must first be cleaned of rust and metal brush;
- the part on which the thread will be cut is securely fixed in a vise or other device in a convenient position (preferably in an upright position);
- 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: you can use used oil and even animal fat;
- 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 of threading dies on lathes to a large extent depends on the design features of the machine itself and is described in detail in the manual for a specific model of a lathe.