Service Home How To Procedures ST Large C-axis & Stabilizer Installation - AD0879
Last updated: 05/20/2025

ST-Large - C-axis & Stabilizer Installation

AD0879

Revision A - 05/2025

Introduction

This procedure shows how to replace a C-axis assembly on ST-40/45 machines and the installation of a C-axis stiffening brace.

This Document Applies to the following Service Kits:

  • 93-5072 C-AX SVC KIT W/ STABILIZER BRACE LRG ST
  • 93-5090 C-AX STABILIZER BRACE KIT

Note : 93-5090 is only compatible to install on P/N 20-10652A C AXIS CARRIER or later revisions. Refer to C-axis carrier identification section below.

Note : 93-5072 is an improved C-axis assembly for deflection reduction and is intended for ST-40 machines with P/N 20-6925B CYL BLOCK C-AXIS HYD ACTUATOR since it replaces it with P/N 20-6925C.

Machine Compatibility :

  •     ST-40/40S/45 after 05/22/2023

Important : These service kits are only compatible with machine that have spindle head casting P/N 20-10675 and later revisions.

Note : It is recommended to use the Haas Fastener Torque Specifications

C-axis Carrier Identification

Stiffening braces are only compatible with P/N 20-10652A and later revisions and not with P/N 20-10652.

If your machine has P/N 20-10652 then proceed to order 93-5072 for a revised assembly and stiffening brace.

Spindle Head Casting Identification

Current production spindle head casting have provision for mounting the stiffening brace [2] as well as the secondary chuck option [1] but older machines only have the secondary chuck provision [3].

Installation

1

Power off the machine and ensure that the HPU gauges read 0 psi.

Disconnect the hydraulic line [1] and lubrication line [2] from the C-axis assembly.

2

Remove hardware [1] and [2] from the C-axis mount [3].

Note : Ensure that the C-axis motor power and encoder cables are disconnected.

3

Completely remove the C-axis assembly as illustrated.

4

Install the C-axis assembly and torque the hardware to specification.

Connect the C-axis lubrication and hydraulic lines.

5

Install the C-axis stiffening brace.

Important : The illustrated brace cannot be installed on a secondary chuck machine

6

Install the C-axis brace.

Align the C-axis engagement offset. Refer to C-Axis - Engagement Offset - Lathe - NGC for detailed instructions.