Applies to machines built from:
The spindle taper is the area inside of the spindle. A spindle taper that is dirty, damaged, or not aligned decreases cutting accuracy and causes an unsatisfactory surface finish.
Press EMERGENCY STOP before you do any of these procedures.
Do these steps monthly**:
- Use a flashlight to visually inspect the spindle taper for signs of wear and damage.
- Clean the spindle taper with a clean, lint-free cloth.
- Put a coat of all-purpose machine oil on the spindle taper with a lightly-oiled lint-free cloth.
|Clean Lint-Free Cloth
||Precision Test Bar
|All-Purpose Machine Oil
||0.0001" Dial Indicator
||Non-Drying High-Spot Paste
Do these steps monthly, or when needed:
- Put the tip of an indicator  against the taper to measure runout. Manually turn the spindle. The total indicated runout (TIR) of the spindle at the taper must not exceed 0.0002" (0.005 mm).
- Put a precision test bar  into the spindle. Put the tip of the indicator against the test bar approximately 6.0"(150 mm) below the gauge line to measure runout. The TIR at 6.0"(150 mm) from the gauge line must not exceed 0.0005" (0.013 mm).
- Put a coat of blue high-spot paste over the entire surface of the taper of a toolholder. Put the toolholder into the spindle.
- Remove the toolholder. The fit into the taper is correct when at least 75% of paste  has been rubbed off. Make sure that the pull stud is not damaged.
Refer to Mill - Tooling - Maintenance. Do the VMC - Spindle - Drawbar - Force Measurement.
note: Best practice is to remove toolholders from the spindle when the machine is not in operation.
**The recommended times are based on the average user. Actual times vary depending on machine usage and the materials being cut. If you machine abrasive materials such as graphite or cast iron, or if you run the machine the machine on multiple shifts per day, the inspections should be more frequent. Likewise, if the machine is rarely used, then the intervals between inspections can be longer.