Install a collet tool , a 3/8" hex socket  into the spindle.
Note: Make sure the collet tool  is very tight to prevent the 3/8" hex socket  from moving during the backlash test.
Put the magnetic test bar  on the left side of the spindle.
Put the dial indicator on test bar  approximately 1" (2.54 cm) from the center of the spindle.
Use the breaker bar to push up the spindle  at about 15 ft-lb (20 N-m), and then release. Set the indicator dial to 0.
Use the breaker bar to push down the spindle  at about 15 ft-lb (20 N-m), and then release.
If the indicator shows more than 0.0005" (0.01 mm), the adjustment of the spindle backlash is necessary.
For this adjustment you must send the rotary to a certified rotary repair facility.
For instructions on where to find a rotary repair facility and how to send your rotary unit, go to www.haascnc.com .