The DIN EN 22568 HSS-G fully ground circular dies for MF metric fine threads are designed for producing external ISO threads according to DIN 13 with fine pitch on rods, pins, studs, special screws, mechanical components and parts that need to be manufactured, reworked or repaired. Compared with standard coarse metric M threads, MF fine threads use a smaller pitch and are suitable when more accurate adjustment, better tightening control, reduced axial movement per revolution and a finer, more stable threaded connection are required.

The fully ground HSS-G high-speed steel construction provides accurate cutting geometry, stable thread profile and consistent thread quality. The ground cutting edges allow smoother machining compared with non-ground tools, improving profile cleanliness, threading repeatability and feed control. The 60° profile, 6g tolerance and closed pre-slotted Form B geometry allow regular external metric fine threads to be produced in accordance with standard thread fits. The closed Form B design provides stable guidance when starting the die on the workpiece, while the pre-slotted construction helps distribute cutting forces and supports correct thread formation.

These dies are suitable for materials with tensile strength up to approximately 800 N/mm², including structural steels, unalloyed steels, free-cutting steels, mild steels and general metallic materials compatible with HSS-G cutting tools. Metric fine threads are particularly useful in mechanical applications where the nominal diameter must maintain a larger resistant section, where axial space is limited or where more accurate component adjustment is required. They are therefore suitable for mechanical workshops, industrial maintenance, toolrooms, automotive applications, mechanical engineering, thread repair and technical components requiring precise threaded connections.

The correct version must be selected according to nominal MF diameter, required fine pitch, outside die diameter, height and compatibility with the die holder being used. The thread pitch must always be checked carefully, because the same nominal diameter can have several MF pitch variants, such as MF10 x 0.75, MF10 x 1.00 and MF10 x 1.25.

To obtain accurate threads, the external workpiece diameter must be prepared correctly, a suitable starting chamfer must be made, the die must be kept coaxial and perpendicular to the component axis, and appropriate cutting lubricant must be used. With fine threads, starting alignment is especially important because the reduced pitch makes the profile more sensitive to misaligned starts, incorrect workpiece diameters or chip accumulation. Misalignment, insufficient lubrication or forced use of the tool can cause incomplete threads, torn profiles, increased cutting effort, premature die wear and poor thread engagement. During machining, progressive cutting and periodic chip breaking are recommended, especially on larger diameters or tougher materials.