Thread Forming Tap Speeds and Feeds Guide
Running forming taps at the correct speed and feed is critical for thread quality, tool life, and production efficiency. This guide provides recommended parameters for HSSE forming taps.
Why Forming Taps Run Faster
Unlike cutting taps, forming taps don’t produce chips. This means there’s no chip evacuation limit, allowing higher cutting speeds. Forming taps typically run at 1.5-2x the speed of cutting taps.
Recommended Cutting Speeds by Material
| Material | Speed (m/min) | Speed (SFM) |
|---|---|---|
| Aluminum | 30-60 | 100-200 |
| Mild Steel | 20-35 | 65-115 |
| Copper & Brass | 30-50 | 100-165 |
| Stainless Steel | 10-20 | 33-65 |
RPM Calculation
RPM = (Cutting Speed x 1000) / (pi x Tap Diameter in mm)
Example: M8x1.25 forming tap in aluminum:
RPM = (30 x 1000) / (3.14 x 8) = 1194 RPM
Feed Rate for Forming Taps
Forming taps are self-feeding. The feed rate equals the thread pitch per revolution:
Feed (mm/rev) = Pitch
For synchronized CNC tapping, set feed = RPM x pitch.
Tapping Torque
Forming taps require 30-50% more torque than cutting taps. Ensure your tapping holder or CNC spindle can deliver sufficient torque, especially for larger sizes.
Best Practices
- Use cutting fluid or tapping paste – forming taps generate heat through friction
- Use rigid tapping on CNC machines – synchronized spindle and feed
- Start with lower speed and increase gradually
- For blind holes, ensure the hole depth is at least 1.5x the thread diameter deeper than required thread depth
- Use the correct forming tap drill size – larger than cutting tap drill
Conclusion
Proper speeds and feeds are essential for forming tap performance. HSSE forming taps can achieve excellent results across a wide material range when run at recommended parameters.