Okuma Howa V35R Spindle Repair

The Okuma Howa V35R is a CNC vertical turning center.  It comes fitted with a grease lubricated and belt driven spindle capable of running up to 2,500 rpm.

CHALLENGE

This Okuma Howa V35R spindle arrived with the drive pulley loose, it has been running loose for a while. The pulley ID and shaft OD are severely fretted from being run with it loose.  Upon disassembly, we noted that the rear shaft threads were damaged from the pulley nut being loose.  The actuator draw tube is severely rusted and pitted were the o-rings sit and the tube itself behind the o-ring grooves.  The ID taper and were the draw tube o-rings ride is also severely rusted and pitted(this will eat o-rings and allow tooling coolant to enter through the nose into the draw tube cavity)(we’ll clean and use as is).  The rear pulley nut face was damaged by the actuator bolts when the nut loosened, and it was missing the locking star washer.  Lastly, the spindle came in without the alignment pin in the lathe taper face.

SOLUTION

The following actions were performed on this Okuma Howa V35R spindle:

• Clean, inspect overall dimensions
• Replace bearings, o-rings, and assembly screws
• Grind, chrome plate, and finish grind the pulley journal oversized,
• Finish grind pulley ID to match oversized pulley journal
• Kiss grind the OD lathe taper and face
• Weld/machine new rear threads
• Machine a new rear shaft pulley nut spacer
• Due to the extensive pitting of the drawbar tube OD and the shaft ID, our customer should remove the tube and re-lubricate to help prevent additional pitting.

RESULT

After reassembly of all components, adjusting bearing preload, and undergoing break-in and testing procedures, this spindle passed our final quality inspection before being returned to our customer with a 1-year warranty.

An email we received from our customer:

Northland,

We been running the spindles for about a month now, runs great. Ya’ll are batting a .1000 right now 3 for 3 spindles running with no problems. Very satisfied, and thanks for checking in.

Mechanic Supervisor