The most efficient method of machining internal grooves in one operation.

Elliott Internal Recessing Unit for fast, efficient, and consistent machining of internal grooves concentric to bores. Minimize your cycle time while eliminating deflection and guaranteeing repeatability.

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Repeatable & Accurate

  • Most efficient method of machining grooves in one operation where close tolerances and finish are critical.
  • Repeatable and accurate for diameter and axial position of grooves and lands (+/- .002″)
  • Due to the unique design, the cutter is supported along it’s entire length by the pilot. This eliminates deflection and ensures precise feature machining with consistent repeatability.


  • Simple to set up and use!
  • There are only two settings required on the Elliott IRU:
    Positional location (using the tool’s adjustable stop collar)
    Groove diameter (Manual machine – adjust limiting nut; CNC/power fed machine – programmed).
  • Can be used on CNC machining centers, special machines, transfer machines and drill presses.

Eliminates Deflection & Chatter

  • The IRU is designed to support the cutter along its entire length, eliminating deflection and creating a precise machined feature.
  • The IRU system pilots in the bore, providing perfect concentricity.
  • Rigidity and accuracy is assured by strategic location of the arms to support the cutting teeth.

Economical & Efficient

  • Machine internal grooves in one operation.
  • Quick cycle time – typical cycle time is less than 15 seconds!
  • Carbide cutters can be resharpened ~2-5 times and can also be replaced.

IRU Components & Operating Procedure

1. Location Pilot (OD ground to suit component bore)

2. Cutter (Replaceable on carrier arm)

3. Adjustment Stop Collar (Actuate IRU with adjustable length of up to .780”)

4. Operating Head Assembly

5. Limiting Nut (To set cutting diameter – manual operation only)

1) The recess system feeds into the work-piece with the pilot locating within the component bore.

2) The operating head or optional nose piece makes contact with either the component face or a fixture plate.

3) While feeding forward, the system is actuated, lifting the cutter exactly perpendicular to the axis of rotation at a 2:1 ratio.

4) This machines all features simultaneously, with perfect concentricity.

Radial cut depth can be controlled by the limiting nut bottoming out or by the CNC program controlling the tool’s feed-depth.

Technical Reference and Downloads

View the Internal Recessing Unit in action: