Service Home How To Procedures Spindle Deflection Test - Lathe - AD0636
Last updated: 03/17/2025

Spindle Deflection Test - Lathe

AD0636

Introduction

This procedure will show you how to measure the deflection on a Lathe spindle.

Tools Required:

  • 0.0001" Dial Indicator with Mag Base
  • Air line with quick disconnect
  • T-0151 A2-8/A2-6 SPINDLE DEFLECTION TOOL KIT 
  • T-0156 A2-5 SPINDLE DEFLECTION TOOL KIT 

 Note: Only one of the above kits needs to be ordered. Choose the one that fits your spindle size. Refer to the Lath Chuck Diameter Chart if needed. 

Note: If you have a non-solid cap and are experiencing high runout and poor surface finish problems follow the Lathe - Spindle Solid Front Cap – Replacement procedure to upgrade to a solid front cap.

Installation

1

Remove the chuck or fixture from the spindle.

Retract the drawtube.

Clean the face of the spindle.

Unscrew the spindle adaptor [1] from the Spindle Deflection Tool.

Align the spindle adapter pilot hole to the spindle drive dog and install the spindle adaptor to the face of the spindle shaft.

Tighten the four 5/16" hex bolts [2].

 

2

The tool mounts to the spindle front cap with 4 bolts.

For 8-Hole Pattern

Remove the 4 bolts shown in figure [1].

For 10-Hole Pattern

Remove the 4 bolts shown in figure [2].

 

 

3

Screw in the Spindle Deflection Tool [1] into the spindle adaptor. 

Align the holes of the tool [2] to the spindle front cap. 

Install the 4 bolts [3] that came with tool.

Note: You may need to push on the tool until the mounting plates and the spindle front cap surfaces are flushed [4].

Tighten the screws.

Make sure all the screws are tight.

 

 

4

Make sure the air switch lever [1] is set to the middle or neutral position.

Connect the airline [2] to the Spindle Deflection tool and set the air regulator [3] to one of the following PSI's based on the spindle size:

  • For A2-5 lathes (T-0156): 80 PSI
  • For A2-6 lathes (T-0151 w/ the adaptors for A2-6 spindle): 54 PSI
  • For A2-8 lathes (T-0151 w/the adaptors for A2-8 spindle): 70 PSI

5

Mount a dial indicator and set the needle to the face of the spindle face [2].

Note:  On the illustration shown the base of the indicator is mounted on the ATP mount face [1]. 

6

Set the dial indicator to zero.

IMPORTANT:  Indicator readings are critical make sure your indicator repeats.  Deflect the dial indicator a few times and make sure it repeats back to zero.

Push Test:

  • Push the air switch lever so the piston pushes into the spindle face.  Record the Push Test indicator value:______________.

  • Return the switch lever to the middle position.  Record the Lost Motion indicator value:_______________.

     NOTE: In the example shown the Push value is 0.0004" 

Pull Test:

  • Push the air switch lever so the piston pulls the spindle face.  Record the Pull Test indicator value:______________.

  • Return the switch lever to the middle position.  Record the Lost Motion indicator value:_______________.

     NOTE: In the example shown the Pull value is 0.0005" 

Total Lost Motion

  • Add the sum of the Push/Pull Test Lost Motion indicator value:______________. 

     NOTE: In the example shown the total lost motion is 0.0002" 

7

The Push, Pull and Total Lost Motion indicator values are NTE the following:

  • Push value: 0.0005"
  • Pull value: 0.0005"
  • Total Lost Motion: 0.0003"

If the values are greater than those listed above contact Haas Service.