The extra-long machine reamers with straight shank and decimal progression, made of HSSE steel, are cutting tools designed for finishing, sizing and dimensional correction of existing holes when machining depth or hole position requires a longer usable reach than standard reamers. They are suitable for mechanical machining operations where a hole must be brought to its final size with accuracy, good roundness, controlled surface finish and dimensional repeatability.

The function of a reamer is to remove a small amount of material from the internal diameter of a hole already produced by drilling, boring or rough machining. A reamer is not intended to create the hole, but to finish it and bring it to the required final dimension. The extra-long version makes it possible to reach deep seats, long through holes, recessed internal holes, areas far from the entry surface and components where a short tool would not provide sufficient reach.

The straight shank allows mounting in drill chucks, collet holders, clamping sleeves and suitable toolholding systems on drilling machines, lathes, milling machines, boring machines, machining centers and CNC machine tools. To obtain an accurate hole, clamping must be stable and coaxial. The longer tool length requires particular attention to system rigidity, as long tools are more sensitive to deflection, vibration and misalignment than short reamers.

The decimal progression allows the most suitable diameter to be selected precisely according to the required final size. This is particularly useful when holes must meet tight tolerances or functional fits with dowel pins, pins, bushes, small shafts, guides, centering components and assembly parts. Closely spaced sizes help match the real production requirement and reduce the risk of selecting a diameter that is not suitable for the required fit.

The HSSE steel construction provides higher wear resistance than standard HSS and ensures good cutting edge stability in professional machining operations. It is suitable for use on steels, alloys, ferrous and non-ferrous materials, depending on cutting parameters, lubrication and machine rigidity. HSSE is especially valued when precision, tool life and reliable performance are required in production or maintenance cycles.

The 6° left-hand spiral flutes support stable and controlled cutting. This geometry helps limit the tendency of the tool to self-feed into the hole and provides more predictable behavior during reaming. In long or deep holes, cutting stability becomes even more important, as vibration or deflection can affect roundness, cylindricity and surface finish.

For best results, the hole must be prepared with the correct stock allowance. If the pre-hole is too small, the reamer must remove too much material, increasing cutting force, heat, tool deflection and cutting edge wear. If the pre-hole is too close to the final size, the reamer may not cut properly over the full surface, leaving irregularities or geometric errors uncorrected.

When using extra-long tools, it is essential to work with regular feed, proper lubrication and good machine alignment. The reamer should enter the hole without forcing and without misalignment. Reverse rotation while the tool is inside the hole should be avoided, and feed should remain constant to reduce scoring, sticking and abnormal wear. Lubrication helps reduce friction and heat, improves chip evacuation and supports a more uniform surface finish.

Typical applications include sizing deep holes, finishing internal cylindrical seats, machining holes for dowel pins and pins, preparing bush seats, restoring holes during maintenance, finishing components for machine tools, fixtures, mechanical assemblies, machined fabrications and precision assembly parts. These tools are used in machine shops, CNC departments, industrial maintenance, automotive, machine building, toolrooms and precision engineering.

To preserve tool precision, the reamer should be protected from impact, oxidation and accidental contact with other tools. Before use, the cutting edges should be checked to ensure they are intact, clean and free from chipping. After use, the tool should be cleaned and stored properly, especially in smaller diameters and long versions, where any damage or deformation can immediately compromise hole quality.

The extra-long HSSE machine reamers with straight shank and decimal progression are therefore a professional solution for finishing deep and hard-to-reach holes. The combination of long series design, HSSE material, 6° left-hand spiral and wide decimal diameter range allows accurate, reliable and controlled hole finishing in industrial applications where hole quality is critical to component performance.