Service Home How To Procedures HSK-A63 Spindle Clamping Unit Replacement
Last updated: 10/09/2025

HSK-A63 Spindle Clamping Unit - Replacement

AD0824

Introduction

This procedure shows how to replace a HSK-A63 Spindle Clamping Unit.

 CAUTION: This procedure is intended for HAAS HSK - A63 spindle only.  Do not use for H-5AX ES779 or ES789 spindles.

This Document Applies to the Following Service Kit:

  • 93-3141 GRIPPER FINGER SET HSK-A63

Tools Required:

  • Long 5mm hex socket bit
  • 24mm wrench
  • Hollow (TSC) A63 tool holder and matching spanner wrench
  • HSK spindle taper wiper
  • METAFLUX grease paste 70-8508 and grease brush
  • Pliers
  • A pick

HSK-A63 - Remove the Clamping Unit

  You should not do mechanical or electrical machine repairs or service procedures unless you are qualified and knowledgeable about the processes.

   Only authorized personnel with the proper training and certification should do this repair procedure.

   All information herein is provided as a courtesy for Haas machine owners for reference and illustrative purposes only. Haas Automation cannot be held responsible for repairs you perform. Only those services and repairs that are provided by authorized Haas Factory Outlet distributors are guaranteed.

 

1

  • Insert a hollow HSK-A63 tool holder without a collet to the spindle - this will prevent the drawbar from rotating 
  • Loosen the locking scew using using a long 5mm hex bit that will reach through the tool holder and a collet spanner wrench on the tool holder to prevent it from rotating
  • Remove the HSK-A63 tool holder from the spindle

2

 
  • Refer to the AD0541 VMC - HSK-A63 Spindle - Replacement for the proper steps to remove the spindle.

Caution: Take great care when handling the spindle.  Do not bump the sensing ring on the guide release. Secure it safely in a fixture on a work bench and protect the coupler and housing from damage. Any impact to the spindle could brinell the bearings and permanently destroy them or significantly reduce their life cycle. Make sure to have to the tools you need to properly secure the spindle before you begin this repair.

  • Unscrew the clamping cone, if it spins with the drawbar, hold the drawbar from the back to prevent it from turning [2]
VMC - HSK-A63 Spindle - Replacement

3

  • Remove each gripper segment [1] x 7 each
  • Use a tilting movement to dislodge the gripper segment from the spacer unit
  • Note: If you are replacing a segment they must be replaced as a set

4

  • Remove O-ring [1] from the drawbar shaft using a pick
  • Remove the spacer unit [2] using pliers
  • Remove the plastic washer [3]
  • Remove the O-ring [4] from the shaft bore using a pick

HSK-A63 - Install New Clamping Unit

1

  • Use only METAFLUX paste 70-8508 to grease the following in the locations show in the image and anywhere there is metal to metal contact:
    • O-rings [1], [3]
    • Gripper Segments [4] x 7
    • Spacer Unit [2] , grease all 7 of the nobs that the grippers rest on
    • Clamping Cone [6]
  • Warning: Everything must be greased generously, if not you will loose clamp force
  • Note: METAFLUX  product is not available from Haas Automation and can be purchased off-the-shelf
  • Installation is reverse of removal
    • Install O-ring [3] using tool T-0118. This tool protects the O-ring from shearing on the threads of the drawbar.
    • To install the gripper segments [4] you hook an edge into the shaft bore groove and then tilt it into place.  You install one segment at a time, being careful to hold all of the previously installed segments into place as you install each one.
    • Note: Make sure the locking screw [5] is in the orientation shown when installed to the clamping cone.  The hex key side of the screw needs to be accessible when the clamping cone is installed. The locking screw does not need grease.
    • Install the clamping cone immediately after to hold the segments into place.
    • Snug the locking screw
  • To finish installation, re-install the spindle to the machine
VMC - HSK-A63 Spindle - Replacement

HSK-A63 - Set Push Out

1

  • Set Push Out:
  • Engage the TRP (Tool Release Piston) so that the drawbar is in the unclamped position
  • With the TRP engaged, use a depth gauge to measure the distance between the face of the clamping cone and the face of the spindle [1]
    • NTE (not to exceed) [0.41 in +/- 0.004 in] OR [10.5 mm +/- 0.1mm]
    • NOTE: For H-5AX HSK A63 spindles the push out distance is NTE (not to exceed) [0.417 in +.003/- 0 in] OR [10.59 mm +/- 0 mm]
  • If the push out is not within the above specification do the following:
  • Loosen the locking screw only 1-2 turns   
    • Note: backing out the locking screw too much can damage the spindle 
  • Unscrew or tighten the clamping cone to adjust the push out distance measured
  • Once set snug the locking screw using a 24mm wrench on the flats of the clamping cone and a 5mm hex bit

2

  • Torque Locking Screw:
  • Insert a hollow HSK-A63 tool holder without a collet to the spindle - this will prevent the drawbar from rotating while you torque the locking screw
    •  Use a long 5mm hex bit that will reach through the tool holder and a collet spanner wrench on the tool holder to prevent it from rotating
  • Torque the locking screw to 20 Ft-lbs  (27 N-m)
  • Check clamp force 2,835 - 4,050 lbs
    • Note: A new unit should be near 4,050 lbs, but if you are simply replacing it after cleaning, slightly lower force is acceptable
    • Once the force drops below 70% of max (2,835 lbs) is when the unit needs to either be re-greased, cleaned, inspected for damage, or have the drawbar inspected for damage as well.
  • To achieve clamp force the clamping unit must be thoroughly greased, the drawbar must not have broken springs, the gripper segments must not be broken, and the spacer unit and gripper segments must not be worn

HSK-A63 - Set Spindle to Tool Changer Alingment