/ THREADING In comparison with other machining operations that use a rotating tool such as drilling, milling and reaming, the THE MULTI- APPLICATION TAP theory associated with tapping presents notably higher levels of complexity due to its variety, volume and the technical/economic scope of the set of variables involved. It occupies preferential positions in the ranking both for operating volumes (third position after drilling and milling) and for financial responsibility - first position - as it is frequently a final operation that completes a multiple machining process. From a conceptual point of view, we could define a thread as a spiral winding of a wire with a defined geometrical profile, the most usual being a 60° triangle, which is the case for DIN-ISO metric system threads and ANSI system threads (USA). From a functional point of view, the most important tasks of threads can be encompassed in 2 large areas: • Principallyasjoining/fasteningelements. • Asactuatingelementstoalesserdegree. JOSÉ LUIS URIZAR, R&D TECHNICAL DIRECTOR AT TIVOLY-NECO The construction or making of internal threads with the use of a tap is one of the most important machining operations in the global context of mechanical manufacture. It is present in practically all industrial sectors, from car to aeronautics through railway, wind energy, ship building, machinery manufacture and capital goods, to the medical industry. 38 / TAP SELECTION THREAD IDENTIFICATION NOMINAL DAT BLIND HOLE THREAD LENGTH CLASS TENSILE STRENGTH HIP TYPE Long, intermediete, short, dust CLASS DIAMETER PITCH TOLERANCE MATERIAL THROUGH HOLE THREAD LENGTH 1,5 xD ALTERNATIVE THREADING METHOD BY MACHINE BY HAND 1,5 xD REMOVE THE CHIP HELICOIDAL TAP 1,5 xD ALTERNATIVE HOST THE CHIP STRAIGHT “C” TAP 1,5 xD BOST THE CHIP “B” SHAPED TAP + RECUBRIMIENTO “STEAM HOMO” HAND TAPS SET IN ALL CASES