At SPS Spindle, we’re used to handling complex spindle repairs, but every so often, a project comes through our doors that truly puts our expertise and teamwork to the test. Recently, a customer sent in an HNK Boring Mill Spindle for repair. Typically, customers ship only the specific spindle head component that requires service. This time, however, we received the entire spindle head assembly, arriving on an 8-foot pallet and weighing nearly 8,000 pounds. The size and weight alone made this a unique and challenging job from the start.
Using a large warehouse spaces, our team carefully disassembled the spindle head to access the internal components in need of attention. As it turned out, sending the complete head was the right call, as it allowed us to uncover several hidden issues that would have gone unnoticed otherwise. Upon inspection, we discovered a bent ball screw that drives the quill, a damaged carrier bearing housing, and a severely worn rear bearing set — ultimately identified as the root cause of failure.
To restore the assembly to peak condition, these components required grinding, chrome plating, and precision regrinding to size. With the repaired and replacement parts in hand, our technicians meticulously reassembled the spindle head, ensuring every tolerance and alignment was correct. Once reassembled, we performed a series of functional tests, including verifying actuation of all drives and confirming smooth, accurate movement of the gear mechanisms. We also powered up the motor and spun the spindle at low speed to check operation, though full RPMs were not possible, as this spindle type requires oil circulation that cannot occur while the machine is open.
The result was a fully restored, heavy-duty HNK spindle ready to get back to work with improved precision and reliability. No matter the size or complexity of the spindle, SPS Spindle has the equipment, expertise, and space to handle the job right. Whether your spindle weighs 80 pounds or 8,000, give us a call or visit spsspindle.com to get started.
