Structural Steel

Hydra high performance replaceable head drills

Hydra Drill

Hydra Drill - Assembly


Hydra Drill - Assembled



Head - Top


Head - Side


Head - Bottom


Features & Benefits


Replaceable heads in tough micrograin carbide and hardened steel body with high gloss nickel plating for high resistance to wear and corrosion. One body accommodates multiple head sizes with no compromise on tool rigidity and structural integrity.

Surface treatment

Ti-phon coating on the drilling heads for high toughness and oxidation stability – enables high speeds and feeds and resists “built-up edge” which is common when machining softer materials.

The self-centering 140º 4-facet split point geometry ensures that required thrust force is low.

Pre-drilling / centre drilling is neither necessary nor recommended.


Cylindrical shank with flat for multi-purpose tool holding. Allows accurate clamping for reliable use of internal coolant. Best results are obtained using hydraulic holders; can also be held in ER type and Weldon type toolholders.


Heads are held securely in place by two screws; the perfect fit of body and head serrations transmits the torque evenly and allows for precise and easy assembly. The slow spiral offers optimised flute volume for efficient chip evacuation.

Internal coolant

Coolant holes in the drill bodies are aligned perfectly with the replaceable heads for efficient delivery of coolant directly to the cutting edge. This not only disperses the heat generated during the hole making process when using high speeds and feeds, but also ensures smooth chip evacuation and long tool life.

Hole depth

Drilling depths of 3xDiameter and 5xDiameter:

metric shank available for the entire range of heads
fractional shank available up to head diameter 30.50mm
Drilling depth of 8xDiameter available on head diameters 13.50mm and larger.

Diameter Range

R950 metric sizes available 12.0mm-42.0mm

Diameter and fractional sizes 15/32”-1.5/8”diameter.

R960 metric sizes available 12.0mm-30.5mm

Diameter and fractional sizes 15/32”-1.3/16” Diameter.

The Hydra for steel head was tested against 2 competitors at manufacturers’ recommended cutting conditions in AMG 1.3. All drills were 12mm in diameter, and drilled to a hole depth of 5 x D. For all 3 tool types, the average number of minutes cut and the average number of metres cut until end of tool life were measured. The R950 drilled for almost 40 minutes, more than twice as long as Competitor 2.

Diameter Range

Diameter Range - Test Results

Customer Benefits

  • High productivity across a wide range of materials, including carbon and alloy steels, stainless steel, titanium, nickel and cast iron.
  • Two head types available – the R960 head has been developed specifically to give optimum performance in stainless steel and cast iron. The R950 head is recommended for steels.
  • Consistently high performance, even after numerous head changes.
  • Reduction in inventory costs – one drill body fits multiple head sizes.
  • Easy and quick head changes with minimal interruptions to the production process. Heads can be changed without removing the body from the machine.
  • Exact fit of head to body maximises tool rigidity for superior hole accuracy and precise tolerances.
  • Shank design allows for versatile tool holding.
  • A choice of drilling depths, up to 8 x diameter.
  • Internal coolant channels provide optimised coolant direction and pressure to give efficient chip evacuation and longer tool life.

The Hydra for stainless steel head was also tested against 2 competitors at manufacturers’ recommended cutting conditions in AMG 2.2. Again, 12mm diameter drills were used to a drilling depth of 5xD. The R960 performance exceeded the nearest competitor, in terms of tool life.

Diameter Range

Diameter Range - Test Results

Drilling Hints & Tips with the Hydra Drill


For maximum chip evacuation performance, coolant use is recommended.

Emulsion coolant concentration of 6 – 8% is recommended for most applications, at a coolant pressure of 20 bar or higher. For high strength steel, stainless steels and tougher drilling applications use a higher concentration of 10 – 12%. In these applications, particularly in stainless steels, it is recommended to use the maximum coolant pressure on the machine.

The Hydra-drill coolant holes provide improved web strength and reduce heat at the cutting edges for increased productivity and longer tool life.


Always use tool holders and collets that provide good concentricity between the drill and the machine spindle. Use a positive stop to prevent the tool from backing up into the holder. Radial runout in the tool assemble must be accurately checked and maintained.


A secure and rigid workpiece will minimise deflection, and allow for better accuracy and true position of the hole.


It is important not to underfeed the drill which will cause it to dwell and dull. This is particularly true in the work hardening materials. Feed rates should be high enough for proper chip formation.

Feeds - Scenarios

  1. Entrance or exit on an angular surface.
  2. Drilling through cross holes.
  3. Interrupt at exit.



Short-hole drill for performance drilling

  • Drill with interchangeable insert
  • High feed rates
  • Good swarf control

System Introduction

With ARNO® AKB drilling system we offer you even more options for performance drilling

  • For high performance drilling in steel and cast materials
  • With through tool coolant
  • Right hand cutting
  • Available in drill depth 2 x D and 3 x D
  • Diameter range 14 mm – 45 mm
  • 14 mm – 30 mm available with 0.5 mm increments
  • 31 mm – 45 mm available with 1.0 mm increments
  • TORX-Plus screws for better locking
  • Inside and outside insert the same
  • Product extension with other drill depths planned for quarter 1 / 2013


  • 4 edges per insert
  • Inserts available in 4 geometries and 4 grades
  • Strong cutting edges and edge radii
  • Generates low axial cutting forces
  • Centre cutting
  • Nickel plated and polished surface for better swarf evacuation
  • No drill retraction marks
  • Strong insert seats
  • Suitable for use on machining centres and lathes
  • High process security due to very strong inserts
  • High productivity due to high feed rate potential
  • Also suitable for cross hole drilling
  • Ideal for drilling out chambers


  1. Improved run-out into the location flat.
  2. Coated and polished holder for improved swarf evacuation and longer tool life.
  3. Improved coolant flow.
  4. TORX-Plus® screw.
  5. 4 Insert geometries for wider application area.
  6. Improved swarf chambers for higher drill performance.
  7. Large ground location flat for optimum tool location.


  1. Shank to DIN 9766 with full length clamping flat.
  2. Through tool coolant.
  3. Extensive tooling identification marking:
    • Ordering code
    • Diameter
    • Torque screw recommendation
    • Spare parts

ARNO® AKB - Designation code - Drill body

Application Area

Drilling into poor surfaces

Drilling into poor surfaces

  • Depending on quality of surface, feed rate may need to be reduced.

Drilling into a cambered surface

Drilling into a cambered surface

  • Reducing feed rate may be required

Drilling into an angle

Drilling into an angle

  • Up to maximum 3o no need to reduce feed rate
  • Above 3o reduce feed rate by 50-70% until drill is in full cut
  • Use strong edge radius

Cross-hole drilling

Cross-hole drilling

  • Reduce feed rate by 50-70%
  • Be aware of swarf jamming
  • Use tough carbide grade
  • Use strong edge radius

Drilling exit into an angle

Drilling exit into an angle

  • Above 3o reduce feed rate by 50-70% until drill is in full cut
  • Use tough carbide grade
  • Use strong edge radius

Drilling of chamber

Drilling of chamber

  • Drill in order as shown on picture
  • Ensure symmetrical machining
  • Reduce feed rate by 50-70%
  • Use tough carbide grade
  • Use strong edge radius

Drilling into groove or large centre bore spot

Drilling into groove or large centre bore spot

  • Facing may be required
  • Reduce feed rate

Drilling into welded seam

Drilling into welded seam

  • Reduce feed rate

Drilling into edge

Drilling into edge

  • Must be prepared by either spot facing or face milling



  • Avoid swarf jamming
  • Possibly reduce diameter of drill body


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