Machine Taps Operation and Maintenance Guide
Machine taps produce internal threads in drilled holes. Proper selection and use prevent tap breakage, the most costly tap-related problem.
I. Tap Selection
- Type: Spiral point taps for through holes push chips forward. Spiral flute taps for blind holes pull chips out. Straight flute taps for short-chipping materials.
- Material: High-speed steel for most materials. Cobalt for harder materials. Carbide for abrasive materials and high production.
- Coating: Titanium nitride for general use. Titanium carbonitride for abrasive materials. Steam oxide for improved lubricity.
- Thread Percentage: Determine the required thread engagement. Typically sixty-five to seventy-five percent is sufficient for most applications.
II. Tapping Procedures
- Drill the correct size hole. Use a tap drill chart to select the appropriate drill diameter.
- Chamfer the hole entrance slightly to guide the tap
- Apply appropriate cutting fluid. Use tapping compound or cutting oil for best results.
- Use the recommended tapping speed based on material and tap type
- For CNC tapping, use synchronous tapping cycles with proper feed and speed synchronization
III. Maintenance
- Inspect taps for wear, chipped cutting edges, or galling after each use
- Clean taps thoroughly to remove chips and built-up material
- Store taps in individual protective sleeves or indexed holders
- Replace taps showing wear before they break in the workpiece
