Chesterfield-based Dormer Pramet (www.dormerpramet.com) has expanded its Shark Line programme of material-specific taps with two new designs.

Each Shark Line tap features a distinctive colour ring on the tool shank, denoting material suitability. The latest additions are to the yellow-ring range (E412) for structural, carbon and low-alloy steels, and to the blue-ring range (E414) for stainless steels.

Both new taps feature a spiral flute angle (of 48deg) that is designed for smooth and fast chip evacuation, allowing the threading of deep blind holes up to 3xD.

According to Dormer Pramet, a special tri-radius profile with constant rake angle along the flute length provides “better control of cutting properties” and prevents the “nesting of chips”.

Chip evacuation is aided further by a back taper that reduces chipping on the last threads of the taps. This feature also reduces torque when the tap reverses, resulting in longer tool life.

Other material types covered by the Shark Line range include red ring for alloy steels, green ring for aluminium and white ring for cast iron.