6.6 Rotary - Backlash Testing

The document below provides a detailed explanation for finding backlash on a Haas Rotary unit.

Note: The following rotary units can not be checked for backlash HRT110, HRT210SHS, HRT160SS /210SS.

Note: HRC units must be plugged, powered up, and disconnected from the air when checking backlash. 

Disconnect the air supply to the rotary.

Put the dial indicator on the rotary as shown in the illustration.

Use an aluminum pry bar (approx. 1" X 1/2" X 18") to push down the spindle [1] at about 15 ft-lb (20 N-m), and then release. Set the indicator dial to 0.

Use the pry bar to push up the spindle [2] 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.

A / B Axis

Place a flat rectangular magnet on the flat part of the TR as shown in the picture. The flat side that will be used to measure backlash should be pointed to the center of rotation of the axis. 

Set the tip of the dial indicator on the flat surface of the magnet as shown in the picture. Pull the bar three times to get the gear teeth fully engaged in one direction and set the dial gage to zero. 

Push the bar in the opposite direction once and read the dial gage. It will show the amount of backlash. 

C Axis

Disconnect the air supply to the rotary.

Put the dial indicator on the rotary as shown in the illustration.

Use an aluminum pry bar (approx. 1" X 1/2" X 18") to push down the spindle [2] at about 15 ft-lb (20 N-m), and then release. Set the indicator dial to 0.

Use the pry bar to push up the spindle [2] at about 15 ft-lb (20 N-m), and then release.

If the indicator [1] 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.

A Axis

Place a magnetic block on the front of the TRT platter as shown in the following image. 

Place the dial gauge tip on side of the block's machined surface. [1]

Note: Measure how far the tip of the indicator is to the  A -Axis of rotation [2].

Zero the indicator, then move the A axis towards the indicator (.001). This will allow enough rotation to engage the gears in one full direction. 

Important: Write down the initial measurement found of the dial indicator as this value will be used later. 

Select the smallest increment (.0001) and move away from the indicator 10 times.

Note: Backlash value will be the difference from the starting measurement subtracted by the final position found on the dial indicator. 

B Axis

Place a magnetic block on the front of the TRT platter as shown in the following image. 

Place the dial gauge tip on side of the block's machined surface. [1]

Note: Measure how far the tip of the indicator is to the  B -Axis of rotation [2].

Zero the indicator, then move the B - Axis towards the indicator (.001). This will allow enough rotation to engage the gears in one full direction. 

Important: Write down the initial measurement found of the dial indicator as this value will be used later. 

Select the smallest increment (.0001) and move away from the indicator 10 times.

Note: Backlash value will be the difference from the starting measurement subtracted by the final position found on the dial indicator. 

Note: The TRT 100 can be back driven so it needs to be plugged into power and disconnected to air.