Pitched at the tool-making industry, the HSB-S Unimax series of ball-nose end mills from Union Tool has been introduced by St Helens-based Rainford Precision Machines Ltd (www.rainfordprecision.com).

The range of small two-flute short-shank end mills is ground to an H4 tolerance of 0/-0.004mm.

Designed for use with precision tool-holders such as shrink-fit types, the HSB-S is offered with an overall length from 35 to 40mm to minimise tool protrusion and maximise rigidity.

Importantly, a key feature of the range is the ±0.003mm tolerance of the ball-nose radius, which is intended to improve surface finish.

HSB-S Unimax cutters can be offered with a ball-nose radius of 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.75, 1, 1.5 or 2mm, and a length of cut from 0.2 to 4mm.

Designated as a series for machining materials of 40HRc and above, these tools feature HardMax coating technology and negative rake-angle geometry to provide a balance of tool hardness, heat-resistance and durability.

The negative rake is reduced as the radius transitions to the periphery, which is said to minimise tool deflection and generate mirror-finish surfaces.
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HSB-S end mills can be applied to steels such as carbon, alloy, pre-hardened and hardened. Additionally, the HardMax coating enables them to process copper, cast iron, titanium alloys and heat-resistant alloys.

For manufacturers seeking a long-necked version for reaching difficult-to-access surfaces, Rainford Precision
offers the HSLB-S series.

Available with a ball-nose radius from 0.1 to 3mm, these cutters have a maximum clearance length of 20mm with an overall length from 35 to 50mm, depending on the selected tool diameter.