The Hydra range of replaceable-head drills from Chesterfield-based Dormer Pramet (
www.dormerpramet.com) has been extended with the addition of a new option for cast iron.
The R970 head has been added to the existing range, which includes drill heads for steel (R950) and stainless steel (R960). All three replaceable heads are suitable for use on the company’s high-speed-steel drill bodies.
A key feature of these drill heads is that they offer easy and quick head changes without the need to remove the tool body from the machine, thereby minimising interruptions to production. Available in 3xD, 5xD and 8xD lengths, all Hydra drills incorporate coolant holes to improve cutting efficiency and swarf evacuation.
Each head type is made from micro-grain carbide designed to provide a good combination of hardness and toughness, while a TiAlN-based coating offers high resistance to oxidisation and wear, as well as additional protection to abrasive materials such as cast iron.
Furthermore, a strong corner design increases stability during drilling and reduces the forces encountered when exiting the workpiece. Dormer Pramet says this improves surface quality and prevents ‘exit burst’, which can occur when drilling granular materials.
Another feature worthy of note is the 140deg split-point geometry, which is said to aid centring and provide low thrust forces when drilling most materials; this capability results in a more-efficient operation that requires less machine power.