Service Home How To Procedures H-5AX - Double Yoke - C-axis NCE 4.5 Replacement - AD0894
Last updated: 04/23/2026

H-5AX - Double Yoke - C-axis NCE 4.5 Replacement

AD0894

Revision C - 11/2025

Introduction

This procedure details the replacement of the 4.5" C-Axis Encoder on all Double Yoke VR and GM machines.

Laser calibration is required to update the compensation table for the corresponding rotary axis following the encoder replacement. 

This document applies to the following Service Kits:

  • 93-4583 NCE 4.5" SERVICE KIT

Tools Required:

  • ANTI-OXIDANT COMPOUND
  • DIELECTRIC GREASE PACK SUPER LUBE
  • 0.006" AMO Shim (.15mm) Only
  • T-0197 NCE AMO SELF COMP CALIBRATION KIT
  • Laptop 
  • Service Key
  • Drop indicator

 Note: Anti-oxidant product and dielectric grease is not available from Haas Automation and can be purchased off-the-shelf.

C-Axis Encoder Removal

1

: Warning: Only certified service personnel should perform this procedure. Reorientation of Z-pulse or Trip-Flag will require laser calibration to populate rotary compensation tables with new, correct, values.

Zero-return all Axis.

 Note: DO NOT zero return the machine with a tool in the spindle.

Press [EMERGENCY STOP].

Remove sheet metal [1] to access the cable connections inside the spindle head.

2

With a Service Key installed, enter service mode.

Press [DIAGNOSTIC].

Navigate to Parameters > Factory.

Set 7.083 C-Axis Linear Scale Enabled to "Scale Disabled".

Power off the machine and turn off the main circuit breaker.

3

 Important: Take a picture and mark the lines so that when reconnecting the lines, matching the correct lines is easier.

Disconnect all the hoses and cables [1]. 

Remove the corrugated tubing on the cables [2] and the cable bracket [3]. 

4

Make note of the tension of the belt by gently pulling on the belt. This will be used as a reference for setting the tension of the belt later in the procedure.  

Remove the pulley mount [1] with the pulley [2], belt [3], and home sensor [4] still installed. 

5

Remove the driven pulley [1].

6

Remove the motor mount [1] with the motor assembly [2] still attached. 

 Note: Leave the O-ring [3] in the groove to use later.

 

7

Disconnect the encoder read head cable [1] from the read head [2].

8

Remove the encoder read head [1] from the read head mount.

9

Remove the encoder read head mount [1].

10

Remove the encoder ring [1].

C-Axis Encoder installation

1

Install the 4.5” encoder ring [1].

The encoder ring should be orientated in line with the spindle holes making sure the z-pulse [2] is facing the encoder read head.

2

Install the encoder read head mount [1] with the two SHCS M8 X 30 bolts.

Torque bolts per the Haas Torque Chart.

3

Clean the back surface of the encoder read head and the mounting surface.

Add a small amount of silicone dielectric grease to encoder cable connection [1]. Grease should be a thin layer but cover all the pins.

Apply two small drops of anti-oxidant to the mounting surface on the read head in the locations shown [2].

4

Install the encoder read head [1] with the SHCS M4 X 0.7 X 10MM bolts.

Use a drop indicator to indicate the AMO read head to encoder ring height.

The encoder read head to ring height should be .118 +/- .019 inches.

Do not torque the bolts, the gap between the encoder ring and the read head will be set later in this procedure. 

5

Verify the O-ring [1] is present.

Install the motor mount [2] with the motor [3] attached using the SHCS M6 X 1.0 X 25MM bolts.

Torque bolts per the Haas Torque Chart.

6

Add blue Loctite to the three SSS M4 X 0.7 X 4MM set screws.

Install the driven pulley [1].

Torque bolts per the Haas Torque Chart.

7

Install the pulley mount [1] with the pulley [2], belt [3], and home sensor [4] attached.

8

Verify the C-Axis home sensor is oriented to a minimum of .250 inches [A] from the end for the slot.

Verify the home sensor bolts are tight.

9

Tighten the belt [1] by pushing the pulley mount [2] away from the spindle. Once the tension matches the tension felt on the original belt, tighten the HHB M6 x 1.0 x 20 bolts [3]. 

Torque bolts per the Haas Torque Chart.

10

Connect the encoder read head cable [1] to the read head [2].

Connect the hoses from the spindle head to the hoses from the CALM Cabinet using the table below.

The Polyethylene (PE) hoses from the spindle head [1, 2, 8, 9] will have push-to-connect fittings.

The Polyurethane (PU) hoses from the spindle head [3, 4, 5, 6, 7] will have compression fittings.

 Note: The TRP hose [7] connects to the 3/8 black hose with the 3/8F NPT 1/4M compression fitting [10].

 

Haas Double Yoke (Before 5/9/2025)
  Head Hose Color     Head Hose Material Zip tie      CALM Hose Color      CALM Hose Material       Zip tie      
Clamp B-Axis     Opaque [2] PE None Opaque PE None
Release B-Axis Blue [8] PE None Blue PE None
Clamp C-Axis Black [9] PE None Black PE None
Release C-Axis Orange [1] PE None Orange PE None
TRP Black [7] PU Black Black PU Black
Taper Pressure Clear [6] PU None Clear PU None
Electrospindle coolant Black [3] PU Green Opaque PE Green
Electrospindle coolant Black [5] PU Green Opaque PE Green
Flood coolant Blue [4] PU Blue Blue PU inner braid Blue
Haas Double Yoke with Chiller (90° Swivel After 5/9/2025)
  Head Hose Color     Head Hose Material Zip tie      CALM Hose Color      CALM Hose Material       Zip tie      
Clamp B-Axis     Opaque [2] PE None Opaque PE None
Release B-Axis Blue [8] PE None Blue PE None
Clamp C-Axis Black [9] PE None Black PE None
Release C-Axis Orange [1] PE None Orange PE None
TRP Black [7] PU Black Black PU Black
Taper Pressure Clear [6] PU None Clear PU None
Electrospindle coolant Black [3] PU Green Opaque PE Green
Electrospindle coolant Black [5] PU Green Opaque PE Green
Flood coolant Black [4] PU Blue Blue PU inner braid Blue

11

Turn on the machine.

Zero return all axis.

 Warning: Do not place the Mag Base anywhere near the Encoder.

Check and document the runout on the OD of the scale encoder ring hub using the uppermost diameter, as shown.

Adjust as necessary. TIR must be 0.0005" or less.

Torque the 4 SHCS M5 X 16 bolts of the encoder ring hub to 30 in-lbf in the star pattern.

After torquing, double check the runout to verify the ring hub has not shifted.

12

Set the gap [1] between the read head and the encoder ring using the .006” shim provided.

Torque bolts per the Haas Torque Chart.

Double check the gap to verify the ring hub has not shifted after torquing.

13

In service mode, press [DIAGNOSTIC].

Navigate to Parameters > Factory.

Set 7.083 C-Axis Linear Scale Enabled to "Scale Linear".

Power cycle the machine.

14

Secure the cables and hoses in the spindle head in their original positions.

Install any sheet metal [1] that was removed to access the cable connections inside the spindle head.

Encoder Self-Calibration

Complete the AMO Encoder Self-Calibration - AD0907 procedure found on the Dealer Only Content page.

 Note: This site is available only to Haas Service Techs.

B and C-Axis Compensation

Use the  H-5AX - VR DOUBLE YOKE - HDC - B/C-AXIS COMPENSATION procedure to check C-Axis geometry. 

If geometry is out, use the procedure to calculate the compensation values. 

Take a back up after populating any of the compensation values and attach it to the machine history.

Tool Changer Alignment

Set the Z Tool Change Offset by following the steps in the Side-Mount Tool Changer - Z-Axis Tool Change Offset – NGC procedure.

 

Set the Spindle orientation by following the steps in the Side-Mount Tool Changer - HSK - Spindle Orientation Offset – NGC procedure.