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  1. Verify that the machine has been powered down and is LOCKED OUT and TAGGED OUT.
  2. Clean the machine spindle with a shop towel and solvent (alcohol or acetone) to remove oil and dirt.
  3. Remove any burrs or embedded debris from the spindle with a honing stone. Do not use emery cloth with the spindle running. This will eventually reduce the spindle diameter and could compromise the clamping ability of the collet to the head.
  4. Measure the spindle with a micrometer at the top, the middle and bottom at 90-degree intervals.  Record the measurements.
  5. Minimum recommended spindle diameter is nominal size -0.005” (-0.127mm).
  6. Inspect the top and bottom collets on both the inside and outside diameters for burrs, galling, chipping and corrosion. Damaged collets can cause damage to the spindle and head when installed and tightened. Replace collets if necessary.
  7. If the spindle is within acceptable tolerance and the collets are free of damage, wipe off spindle with a clean shop towel and install the lower collet on the spindle. It may be necessary to spread the collet slightly to get it started.


  1. Clean both the top and bottom collet mating surfaces of the head and the internal bore of the head to remove any oil and dirt.
  2. Inspect both collet mating surfaces of the head for damage, burrs or embedded foreign matter. Any burrs or embedded material can be removed using a small round honing stone. 
  3. With the lower collet already installed, position the head on top of the spindle. Slowly lower the head in a rotating motion to help align the internal bore of the head with the spindle. Clearance between the head bore and spindle is tight. Slowly lower the head to the bottom of the spindle. 
  4. Install top collet, spacer (if required), washer and nut. To prevent galling and ensure uniform torqueing pressure, use anti-seize compound on the washer and nut. 


  1. Verify that the machine has been powered down and is LOCKED OUT and TAGGED OUT.
  2. Remove nut, washer and spacer.
  3. Remove top collet. A small blade (screwdriver or knife) works well for spreading the collet during removal.
  4. Lift head slowly, straight up.
  5. Place head on a clean surface.