Buy Metric Spiral Point Taps Online in Australia
Metric Spiral Point Taps — Quick Reference
Spiral point taps (also called gun taps or bull-nose taps) are CNC + machine taps designed for THROUGH HOLES. The angled flutes at the cutting end push chips AHEAD of the tap, ejecting them out the bottom of the hole — preventing the chip-packing that breaks taps in machine tapping. Use spiral point in through-holes only; for blind holes, use spiral FLUTE taps (which pull chips back out). AIMS stocks Sutton, Bordo, Goliath and Maxigear in standard metric sizes from M2 to M24.
| Tap Size | Pitch | Tap Drill Ø (Coarse) | Common Use |
|---|---|---|---|
| M3 × 0.5 | 0.5 mm | 2.5 mm | Small precision tapping, electronics, instrument work |
| M4 × 0.7 | 0.7 mm | 3.3 mm | Small machinery, light assembly |
| M5 × 0.8 | 0.8 mm | 4.2 mm | General light machinery |
| M6 × 1.0 | 1.0 mm | 5.0 mm | Workshop default — most common machine tapping size |
| M8 × 1.25 | 1.25 mm | 6.8 mm | Standard machinery + automotive — high-volume tapping |
| M10 × 1.5 | 1.5 mm | 8.5 mm | Medium fasteners, machinery, brackets |
| M12 × 1.75 | 1.75 mm | 10.25 mm | Structural fasteners, heavier machinery |
| M14 × 2.0 | 2.0 mm | 12.0 mm | Heavy machinery, structural connections |
| M16 × 2.0 | 2.0 mm | 14.0 mm | Structural fasteners, heavy industrial |
| M20 × 2.5 | 2.5 mm | 17.5 mm | Heavy industrial, large machinery mounts |
| M24 × 3.0 | 3.0 mm | 21.0 mm | Very heavy structural + industrial fastening |
Spiral Point vs Spiral Flute vs Hand Taps
Three machine tap types, each suited to a different hole type:
- Spiral Point (Gun Tap): Through holes — angled flutes EJECT chips ahead of the tap, out the bottom of the hole. Fast, high-production tapping. Cannot be used in blind holes (no chip evacuation).
- Spiral Flute: Blind holes — helical flutes PULL chips back out the top of the hole. Use where the hole has a closed bottom. Slightly slower than spiral point.
- Hand Taps (Taper / Plug / Bottoming): Manual or low-speed machine work — straight flutes hold chips in the flute pockets, then chips evacuated by backing out the tap. Three-tap set for hand tapping deep holes.
Materials & Coatings
AIMS stocks spiral point taps in HSS (high-speed steel) standard grade and HSS-E (cobalt-fortified) for harder materials like stainless steel and tough alloys. TiN (Titanium Nitride) coating extends tool life 2-3× in steel applications; TiCN coating suits longer-life work in carbon steels. For aluminium-specific spiral point taps with polished flutes (prevent loading), check the dedicated aluminium-cutting variants.
Cutting Conditions
Spiral point taps run at moderate speeds — typically 50-80% of drilling speed for the same material. For mild steel: 60-100 RPM with 6-9 mm/rev feed. For stainless: 30-50 RPM with cutting fluid. Always use a tapping head or rigid-tap-capable CNC cycle — these taps DO NOT tolerate the misalignment of a standard chuck. For tap drill size reference and coarse vs fine pitch selection, see our threading tap size chart.
Common Issues
- Tap breakage in steel: usually caused by undersized tap drill (chip load too high). Check drill size against pitch.
- Poor thread surface finish: usually cutting speed too high or insufficient cutting fluid.
- Tap walking off-centre: tapping head misaligned or workpiece not square to spindle.
Companion Ranges
For BLIND holes, use metric spiral flute taps. For MANUAL tapping, use metric hand taps. For die nuts (chasing damaged threads), see die nuts. For complete threading range, see threading tools. For tap wrench selection (manual driving), see tap wrenches.
People Also Ask — Metric Spiral Point Taps
Q: When should I use a spiral point (gun) tap?
Spiral point taps are designed for through holes. The angled flutes at the cutting edge push chips forward, ahead of the tap, so they exit the bottom of a through hole rather than packing back up the flutes. This makes spiral point taps fast and reliable in through-hole tapping with machine or hand-driven use. Never use them in blind holes — chips have nowhere to go and pack tightly enough to snap the tap.
Q: What's the difference between spiral point and spiral flute taps?
Spiral point taps have straight flutes with a spiral angle ground only at the cutting tip — they push chips forward (use in through holes). Spiral flute taps have spiralled flutes the full length of the tap, designed to pull chips backward, up out of the hole (use in blind holes). Pick the tap to match the hole — wrong choice causes chip jamming and tap breakage.
Q: What materials suit spiral point taps?
Spiral point taps work well in most ductile materials — mild steel, free-machining steel, aluminium, brass, and most stainless steels. They're particularly suited to longer chip materials where the chip evacuation is most critical. For very hard or brittle materials, dedicated taps with different geometry may serve better. Match HSS for general work, HSS-Cobalt for stainless and tougher alloys.
Q: What tap drill do I use with a metric spiral point tap?
Same as for a standard hand tap of the same thread size — the quick formula for metric coarse is: tap drill diameter = thread diameter minus pitch. So M8 x 1.25 uses 6.8mm drill (8 - 1.25 = 6.75, rounded to 6.8). M10 x 1.5 uses 8.5mm. For metric fine, the drill is slightly larger because the pitch is smaller. Tap drill charts cover all standard sizes.
Q: Why is my spiral point tap snapping?
Common causes: using in a blind hole (chips have nowhere to go), tap drill too small (excessive cutting torque), no cutting fluid (heat builds in the cutting edges), not starting square to the work (side-load fractures the tap), or feeding too aggressively. Also check the tap isn't blunt from prior heavy use — dull taps generate more heat and torque than sharp ones.