Tapping Speeds & Feeds Calculator 2026
Calculate optimal tapping parameters, tap drill sizes, and cycle times. Supports metric and imperial threads with spiral point, spiral flute, and forming taps.
Calculate Tapping Parameters
Tapping Guide: Thread Cutting Fundamentals
Tapping is one of the most demanding machining operations. Unlike other cutting processes, the tap must reverse through the freshly cut threads. Proper tap selection, correct speeds, and adequate lubrication are essential for success and tool life.
Common Metric Thread Tap Drills
| Thread | Coarse Pitch | Tap Drill (75%) | Fine Pitch | Tap Drill Fine |
|---|---|---|---|---|
| M2 | 0.4mm | Ø1.6mm | 0.25mm | Ø1.80mm |
| M2.5 | 0.45mm | Ø2.05mm | 0.35mm | Ø2.22mm |
| M3 | 0.5mm | Ø2.5mm | 0.35mm | Ø2.72mm |
| M4 | 0.7mm | Ø3.3mm | 0.5mm | Ø3.59mm |
| M5 | 0.8mm | Ø4.2mm | 0.5mm | Ø4.59mm |
| M6 | 1mm | Ø5mm | 0.75mm | Ø5.39mm |
| M8 | 1.25mm | Ø6.8mm | 1mm | Ø7.19mm |
| M10 | 1.5mm | Ø8.5mm | 1.25mm | Ø8.99mm |
Tap Type Selection Guide
🔵 Through Holes
Use: Spiral Point (Gun Tap)
Pushes chips forward through the hole. Fast, reliable, and the most common choice for production tapping of through holes.
🟣 Blind Holes
Use: Spiral Flute Tap
Pulls chips UP and out of the hole. Essential for blind holes where chips cannot exit forward. Slower but prevents chip packing.
🟢 Ductile Materials
Use: Thread Forming (Roll) Tap
No chips - displaces material to form threads. 3× tool life, stronger threads. Works in aluminum, mild steel, brass, copper.
🟠 Large/Critical Threads
Use: Thread Mill
Interpolated milling. Cannot break off in hole like taps. Ideal for expensive parts, large threads (>M16), different pitches.
Common Tapping Problems & Solutions
| Problem | Common Causes | Solutions |
|---|---|---|
| Tap Breakage | Chips, speed, undersized hole | Correct tap type, reduce speed, verify tap drill |
| Oversized Threads | Worn tap, misalignment | Replace tap, improve fixturing |
| Torn Threads | No lubrication, dull tap | Use cutting oil, sharpen/replace tap |
| Short Tool Life | Material, speed, no coolant | Use coated taps, reduce speed, add coolant |
Frequently Asked Questions
Tapping speeds are typically 30-50% slower than drilling. For mild steel with HSS spiral point: 10-20 m/min (30-60 SFM). Aluminum: 20-40 m/min. Stainless steel: 4-8 m/min. The feed rate MUST equal pitch × RPM for rigid tapping. Faster is not always better - broken taps are expensive.