Spindle image provided by GMN USA

Spindle image provided by GMN USA

In the manufacturing industry, spindles are key components used to perform tasks in machining jobs such as cutting, drilling, milling, and grinding. Spindle tools are mounted on rotating shafts driven by motors or other power sources. These tools are crucial for shaping raw materials such as metal, plastic, wood, and composites into finished products.

Spindle issues range from deflection, runout, or instability from inconsistent cutting forces and tool engagement leading to poor machining accuracy and repeatability. Spindle issues can also lead to overheating conditions that cause abnormal temperature readings or fluctuations in spindle temperature during operation. By recognizing these signs of spindle deterioration and properly repairing the spindle, manufacturers can minimize downtime, improve productivity, and extend the lifespan of spindle systems in machining operations.

Spindle problems can arise from inadequate lubrication, bearing wear, or internal friction which generate excessive heat, leading to thermal expansion, reduced dimensional stability, and potential thermal damage to spindle components.

Spindles normally produce noise and vibration during regular operations.  If sudden changes occur, such as unusual grinding, squealing, rattling noises, or if the machine vibrates excessively, it could indicate issues with the spindle. These symptoms might suggest problems such as bearing wear, misalignment, imbalanced tooling, or internal component damage within the spindle assembly.

Spindle Repair Process:

Spindle performance and machine dynamics diminish when spindles start to wear out. Spindle overloading can cause mechanical and thermal stresses, deflection, vibration, and accelerated wear on spindle components, leading to premature failure and reduced machining quality.

GMN USA can help you repair any spindle tools that require careful inspection, diagnosis, and sometimes replacement of damaged components. GMN USA is focused on providing the best spindle process available by improving the lifetime and capability of your machine tool. Our spindle repair process involves:

Spindle Inspection:

GMN USA has a team of experienced engineers who thoroughly examine the spindle tool for any visible signs of damage, wear, or deformation. Our team checks for chips, cracks, excessive wear on cutting edges, or any other irregularities that may affect performance.

Spindle Disassembly:

The spindle disassembly process at GMN USA is completed by a detail-oriented team of engineers, machinists, and spindle technicians. We understand that the proper disassembly techniques are crucial to ensuring no components are damaged, which could lead to excessive lead time of a spindle repair.

Damage Report:

A comprehensive damage report outlines the various issues affecting the CNC spindles, highlighting the areas that require attention and repair to restore optimal functionality and performance.

Quote for Repairs:

From the damage report, a quote is created based on the extent of damage and specific repairs required for each spindle. Once the quote is approved, GMN USA will proceed with scheduling the repairs, ordering any necessary parts, and estimated delivery.

Refurbished Parts:

Our team thoroughly inspects each component of the spindle tool, including inserts, cutting edges, bearings, and shafts. Any damaged parts or parts that exhibit excessive wear are refurbished in our facility to meet quality standards.  Parts that cannot be refurbished are replaced.

Ultrasonic Cleaning:

Spindle environments in machine operations are often exposed to coolant mists, airborne dust, chips, and other debris generated during cutting processes, which can enter the spindle system and cause damage. Contamination can lead to abrasive wear, corrosion, blockages, and impaired lubrication, compromising spindle performance and reliability.

Cleaning all components of the spindle tool using appropriate solvents and cleaning solution to remove dirt, debris, and built-up residues is very important. The cleaning process involves the use of brushes, compressed air, or other cleaning tools to ensure thorough cleaning, especially in hard-to-reach areas.


GMN USA uses dynamic balancing equipment and detailed instructions to achieve an optimal spindle balancing tolerance, which is essential for reducing vibration and extending the life of the tool. All rotating components are pre-balanced to G1 tolerances to ensure the spindles have the lowest vibration level possible. This, in turn will deliver to the customer the best surface finish and longest bearing lifetimes. Minimizing the vibration levels will also keep the noise level of the machine to a minimum in atmospheres which have low noise level requirements.

Finishing Process:

Our team of experts at GMN USA reassemble the spindle tool ensuring that all components are properly aligned and secured. The reassembly process is performed following the manufacturer’s specifications or assembly instructions to ensure correct placement and orientation of parts.  We then polish the exterior of the spindles to guarantee your spindle is in “like-new” condition.

Testing and Calibration:

After reassembly, our team of experts at GMN USA, test the spindle tool to ensure proper functionality and performance. The testing and calibration steps are performed to OEM standards. All spindles are tested at the maximum operating RPM and are trim balanced at speed to ensure the lowest level of vibration is achieved. Drawbar position sensors are set, and drawbar pull force is measured. Radial runout of 2 microns and axial runout of 1 micron is guaranteed after every spindle repair.

Shipping & Documentation:

At the end of the repair process GMN USA produces detailed records, including inspection findings, replacement parts, maintenance procedures, and test results. This information helps track the history of the spindle tool and facilitates future maintenance and troubleshooting efforts.


Using worn or damaged spindles can produce vibrations leading to catastrophic machine damage. During operation, spindles may be subjected to excessive loads, speeds, feeds, or cutting forces beyond their design limits, either due to improper programming, tooling, fixturing, or operator error. Repairing industrial CNC spindles requires expertise and precision to ensure optimal performance and reliability. GMN USA has the experience and the knowledge required to repair spindles for every type of application. Discover how GMN USA can help you repair your spindles to maximize production time.