Tap and die#Tap

A die cutting ( cutting blade, in German-speaking Switzerland also called Filière ) is a metalworking tool for cutting external threads. It belongs to the tooling and machining Category machining. The appropriate tool for cutting internal threads is the tap.

Appearance and function

A cutting iron is cylindrical and has inside - depending on size - three or more cutting on. Between the cutting cavities in the form of holes are provided, which roll and dissipate the resulting shavings. There are also hexagonal dies, in order to be able to move the cutting iron in inaccessible locations with ring or open-end wrench ( especially for repair purposes).

The outer teeth are flattened. Characterized the gate of the wear on the one hand facilitates further reduced, and when cutting each tooth assumes a chip approximately the same width. The inner teeth of the leadership of the die is used only in the already cut part of the thread.

A die cutting is constructed symmetrically, so that a cut in both axial directions is possible. On the outer shell of the cylinder are three or four conical depressions with which the cutting iron by means of screws can be secured in an appropriate holder against rotation. The sometimes existing groove serves the radial adjustment by the inevitable cutting edge wear. With an addition to the retaining screws at the periphery of the cutting iron holder attached to a slotted screw cutting dies can be spread to generate excess thread for the tighter fit of the screw

Dies are usually made of high speed steel (HSS ).

Standardization

Dies are in accordance with DIN EN 22568, DIN 223 previously standardized.

Application

For cutting an external thread, the workpiece must already have the nominal diameter of the desired thread. The workpiece is clamped to the side which is to receive the threaded upward in a vice. The dies is applied and rotated until the desired length of the thread is reached. It is recommended that the cutting iron to turn back between short so that the chip breaking, falling out and not clog up the threads. Lubrication with cutting oil or another oil, such as canola oil is highly recommended. It reduces the effort and increases the service life (durability ) of the cutting iron.

Threads are slightly slightly oblique cutting by hand. To prevent this, it is convenient to the blank one - adapted to the respective core diameter - 45 ° bevel for better and easier " cutting " of the thread to be missed. If precision is required, it shall be ensured that the cutting iron is perpendicular to the thread axis. This can be done eg by clamping the workpiece in the chuck of a lathe and pinching the iron between the workpiece and tailstock. The lining of the rotating machine should then be rotated by hand. To avoid the cutting iron tilting guide bushings can be used in the die holder.

External thread can generally be cut with the thread cutting device of a lathe, if the thread is not so long and thin that bends away the workpiece. However, this is associated with a significantly higher cost.

See also: Taps, list of tools, metric ISO threads