Precision Measurement, Drives & Maintenance Systems
Micrometers, dial indicators, torque wrenches, soft foot, thermal growth, keyways, oil analysis, VFDs, VFD-induced bearing fluting (EDM), shaft grounding rings, hybrid ceramic bearings, PLCs, and CMMS - aligned to the 2023 RSOS.
- Use micrometers, dial indicators, and feeler gauges for precision measurement
- Apply torque wrenches and correct soft foot and thermal growth
- Install keyways, splines, and press fits correctly
- Interpret oil analysis reports and manage lubrication programs
- Understand motor starters, VFDs, and PLC basics for millwrights
- Explain the EDM mechanism by which VFDs cause bearing fluting and identify the characteristic washboard damage pattern
- Select and install shaft grounding rings, hybrid ceramic bearings, or insulated housings to prevent VFD bearing current damage
Lesson 1
Micrometers, Dial Indicators & Feeler Gauges
Precision Measurement Tools
| Tool | Resolution | Application |
|---|---|---|
| Outside micrometer | 0.001" or 0.01 mm | Shaft diameter, part dimensions |
| Inside micrometer | 0.001" | Bore diameter, housing dimensions |
| Dial indicator | 0.001" or 0.01 mm | Shaft runout, alignment, backlash |
| Feeler gauge | 0.001" to 0.025" | Clearance checks, soft foot |
| Dial caliper | 0.001" | Quick dimension checks |
Reading a Micrometer
Zero Check
Always zero-check a micrometer before use by closing it on a gauge block or the ratchet stop. If it does not read zero, adjust the zero before measuring.
Shaft Runout
Shaft runout is the deviation from true rotation during spinning. It is measured by placing a dial indicator on the shaft surface and rotating the shaft one full turn. The Total Indicator Reading (TIR) represents the runout. Excessive runout indicates a bent shaft, improper machining, or bearing problems.
Micrometers measure to 0.001 inch precision. Always zero-check before use. Dial indicators measure movement and shaft runout. Feeler gauges check clearances. Match the tool precision to the measurement requirement.