This procedure explains how to replace the Captive Stub Shaft Compensating Coolant Union and the transfer tube on the vertical 50 taper mill. Skip the Transfer Tube - Replacement Section if you are only replacing the compensating coolant union.

Note: This image shows the two types of Captive Stub Shaft TSC Union out in the field, the functionality is the same for both.

For the Non-Captive Stub Shaft Compensating TSC Union Replacement, refer to the: Mill 50 Taper - TSC - Compensating Union and Threadless Transfer Tube - Replacement.
Note: If you are unsure which commpensating TSC union is installed on the machine, refer to the Compensating TSC Union - Identification Guide.

Note: For troubleshooting information, refer to the TSC Compensating Union Troubleshooting Guide.  

Tools Required:

• Spindle Lock Tool (T-2080)
• Extra-long 5mm Allen Wrench

Machine Requirements:

• Software Version 100.22.000.1000 or higher

The compensating coolant union is located on top of the tool release piston (TRP).

Disconnect the TSC hose [1], air line [2], and the drain line [3] from the union.

Remove the union bolts [4].

Use a 5mm hex T-Handle or Allen Wrench to un-thread the union stub shaft from the motor [5].
Note: The TSC shaft has left-hand threads.

Once the stub shaft is un-threaded from the motor mount, remove the union [6].

Remove the snap ring [1] that keeps the transfer tube [2] bearings in place.

Pull the transfer tube assembly [2] out of the TRP.

Important: Do not use the pliers to pull the transfer tube out. This will damage the transfer tube. If the transfer tube is stuck, insert Ø0.25"X 24.0" rod through the bottom of the spindle and gently tap the transfer tube out.

Inspect and clean the bore [1] of the transfer tube bearing retainer.

Make sure that the hex and the o-rings [2] on the bottom of the transfer tube are free of defects.

Apply Red-I grease to the o-rings and the hex [2].

Insert the transfer tube into the TRP until you feel that it contacts the drawbar.

While gently pressing down, slowly rotate the transfer tube to align the hex on the transfer tube with the receiving hex on the drawbar and then firmly press the transfer tube down into the drawbar.

Important: Never use a mallet or any other excessive force to drive the transfer tube down. If the hand force is not enough to seat the transfer tube, remove the TRP and inspect the bore on top of the drawbar.

Install the replacement snap ring [3] over the transfer tube bearing. Make sure that the snap ring is fully seated in the groove on the bearing retainer.

Clean and inspect the Stub Shaft for any burrs or imperfections.

Add 1 drop of BLUE thread locker [1] applied to the threads of the Stub Shaft.

IMPORTANT: DO NOT DISASSEMBLE THE TSC UNION.

Check that the orientation of the elbow fitting [1] is as shown.

Check the orientation of the Vacuum Generator. It should be oriented as shown in the image [2].

Make sure spindle is still locked using T-2080.

Inspect the top of the transfer tube for any debris or damage.

Make sure the top of the bearing holder is flat and does not have any high spots stone the surface if necessary [1].

Place the union on the bearing holder and thread the Stub Shaft [2] onto the transfer tube using a 5mm hex T-Handle or Allen Wrench.
 Note: The TSC shaft has left-hand threads.

Install and tighten the four mounting bolts [3] and back them off 1/4 turn.

While rotating the spindle by hand, gradually tighten and then torque the mounting bolts in the criss-cross pattern.

 Note: Refer to the Haas Fastener Torque Specifications for the correct torque value.

Note: A flat ended dowel pin or other cylindrical part that is 0.275 inches in diameter and at least 2.6 inches long is needed for this step.

Insert your dowel pin [1] into the top JIC fitting [2] until you feel it contact the piston [3].

Note: The top cover and TSC vacuum generator has been removed in this image to illustrate the piston. Do not disassemble the union.

Press downwards until you feel the piston [3] bottom out or contact the shaft [4] to eliminate the gap [5]. The piston will move about 0.040".

Reattach the hoses to the coolant union.

Run the spindle motor at 100 RPM and verify the union is not rubbing on the shaft. Gradually increase the spindle speed from 100 to the max RPM and check the coolant union for abnormal noise and vibration.

Reattach the TSC hose [1], air line [2], and the drain line [3] from the union.

Run the spindle motor at 100 RPM and verify the union is not rubbing on the shaft. Gradually increase the spindle speed from 100 to the max RPM and check the coolant union for abnormal noise and vibration.

If the TSC is orientated with the elbow fitting side connected to the TSC Union [1] re-orient the hose so that the non-elbow side is connected to the TSC Union [2].