The taper reamers for injection holes with straight shank, made of HSSE steel, 42° left-hand spiral and 5% taper / 1°25’56” per side, are cutting tools designed for finishing, sizing and geometric correction of existing tapered holes. They are used when the hole must not be simply cylindrical, but must have a controlled, accurate and repeatable taper, suitable for technical applications where the internal hole shape directly affects flow, entry, fitting or component function.

A reamer is not intended to create the hole from solid material, but to finish a seat already prepared by drilling, pre-reaming, boring or preliminary machining. The tool removes a controlled amount of material and brings the hole to the required final geometry. The 5% taper, corresponding to 1°25’56” per side, allows a regular internal tapered surface to be produced, suitable for injection holes, calibrated passages, tapered seats and components where taper accuracy is essential.

The straight shank allows mounting in drill chucks, collet holders, clamping sleeves and suitable toolholding systems on drilling machines, lathes, milling machines, boring machines and CNC machining centers. For accurate machining, clamping must be stable, coaxial and low-runout. Final tapered hole quality depends not only on the tool, but also on machine rigidity, toolholder accuracy, alignment between tool and hole and stable workpiece clamping.

The HSSE steel construction provides higher wear resistance than standard HSS and ensures good cutting edge stability in professional machining. It is suitable for steels, alloys, cast irons, ferrous and non-ferrous materials, depending on the workpiece material, lubrication, stock allowance and cutting parameters. HSSE is a reliable choice when accuracy, tool life and finishing quality are required.

The 42° left-hand spiral flutes support stable and controlled machining. The pronounced helix contributes to chip management, improves cutting continuity and helps obtain a more uniform surface along the tapered hole geometry. This configuration is especially useful when good finish, dimensional control and regular internal profile quality are required.

For best results, the hole must be correctly prepared before reaming. The pre-hole must be consistent with the taper to be produced and must leave a suitable stock allowance. If the pre-hole is too small, cutting force, heat, wear and risk of sticking increase. If the pre-hole is too close to the final size, the reamer may not cut uniformly along the entire surface, leaving defects, scoring or areas that are not properly calibrated.

During use, constant feed, suitable lubrication and accurate alignment between tool and hole are recommended. The reamer should enter the seat without forcing and without misalignment, as centering errors may cause uneven taper, ovality, scoring, vibration or loss of accuracy. Reverse rotation while the tool is inside the hole should be avoided, as it may damage the cutting edges and compromise the machined surface.

These reamers are used in machine shops, CNC departments, mold making, industrial maintenance, automotive, toolrooms, technical component production and subcontract machining. They are particularly suitable for injection holes, calibrated passages, tapered entries, technical seats, special components and operations where the internal hole geometry must comply with a precise and repeatable taper.

The HSSE taper reamers for injection holes with straight shank, 42° left-hand spiral and 5% taper / 1°25’56” per side are a professional solution for producing and finishing tapered holes on conventional and CNC machine tools. The combination of specific geometry, HSSE steel, straight shank and pronounced left-hand spiral enables reliable machining, good dimensional control and consistent internal surface quality.