Service Home How To Procedures ST - Tailstock Parallelism to Z-Axis Correction
Last updated: 02/01/2021

ST - Tailstock Parallelism to Z-Axis Correction

Introduction

This procedure shows how to correct the alignment of the tailstock assembly [1] to the Z Axis [2].

1

Refer to ST Lathe Alignment Indicating Zones procedure to measure the Tailstock Parallelism to the Z-Axis. Procede with the procedure if the tailstock needs correction.

Record the amount of misalignment and direction of error for Top of Bar and Side of Bar.

Top of Bar Alignment Correction

1

1. Loosen the (4) screws only enough to let you replace the shims in the steps that follow.

2. Remove the front shim.

Note: The attached hydraulic cylinder or motor causes the tailstock to lean back. This allows you to remove the shim.

3. Replace the shim with a shim of different thickness to correct the alignment.

Note: For shim sizes, refer to: Shim Kit Check List - ST Lathes.

4. Turn the jack screw clockwise a small amount to raise the tailstock casting or use a pry bar to lift the casting.

2

1. Replace the rearshim with a shim of different thickness to correct the alignment.

 Note: For shim sizes, refer to: Shim Kit Check List - ST Lathes.

2. Turn the jack screw counterclockwise to lower the casting.

3. Tighten to approximately half of the specified torque the (4) screws for the tailstock casting.

Note: For torque values, refer to Haas Fastener Torque Specifications.

4. Measure the alignment on the top of the alignment tool to verify the alignment is correct. If correct, torque the (4) screws for the tailstock casting.

Side of Bar Alignment Correction

1

1. Loosen the (4) screws a small amount to let you control the adjustment in the steps that follow.

Note: After you loosen the screws, tighten them enough to let you control the adjustment, but keep them loose enough to let you correct the alignment. This is approximately 5-10 ft-lb (7-14 Nm).

2. Tighten one screw to approximately 20 ft-lb (27 Nm) to use as a pivot in the steps that follow.

 Note: Keep the pivot screw loose enough to allow the casting to rotate, but tight enough to prevent unwanted movement.

3. Find the (4) jack screws. There are two jack screws [3] in the front.

4. And there are two jack screws [2] in the rear.

2

1. Turn the jack screw counter-clockwise to make space between the jack screw [1] and the dowel pin [2].

Note: This example show a very large space for illustration. It is unlikely your adjustment will be this large.

2. Turn the opposite jack screw clockwise to press the jack screw [1] against the dowel pin [2] and pull the tailstock casting into alignment.

3. Adjust the jack screws until the alignment is correct.

4. Tighten to approximately half of the specified torque the (4) screws for the tailstock casting. Measure the alignment on the top and side of the alignment tool to verify the alignment is correct. If correct, torque the (4) screws for the tailstock casting.

Note: For torque values, refer to Haas Fastener Torque Specifications.

Z-Axis To B-Axis Parallelism Tailstock

1

Refer to ST Lathe Alignment Indicating Zones procedure to measure the Z-Axis To B-Axis Parallelism Tailstock.