Buy Imperial Hand Taps Online in Australia
Imperial hand taps are the traditional tooling for cutting inch-based threads by hand or at low spindle speeds. Each tap has straight flutes and a tapered lead, designed to be turned with a tap wrench while cutting fluid is applied. The three-piece sequence — taper, intermediate, bottoming — lets you start a thread cleanly and finish it close to the bottom of a blind hole.
AIMS stocks 63 imperial hand taps across BSW, BSF, UNC, UNF and BA thread forms, drawn from Sutton (Australian-made HSS) and Goliath (UK heritage HSS).
Imperial Hand Tap Selection — Quick Reference
Imperial hand taps cut inch-based threads by hand or low-spindle-speed machine. Straight flutes + tapered lead designed for tap-wrench operation with cutting fluid. Three-piece sequence — taper + intermediate + bottoming — to start clean + finish close to bottom of blind hole.
| Thread System | Best For | Common Sizes |
|---|---|---|
| UNC (Unified Coarse) | US-origin equipment + automotive + general imperial | #4 to 1" workshop range |
| UNF (Unified Fine) | Aerospace + precision automotive + fine-thread | 1/4"-28 / 5/16"-24 / 3/8"-24 / 1/2"-20 |
| BSW (British Standard Whitworth) | Older AU + UK machinery + vintage equipment | 1/4" – 3/4" workshop range |
| BSF (British Standard Fine) | Older UK precision fine-thread | 1/4" – 3/4" |
| BSP (Pipe Thread) | Pipe + plumbing thread sealing AU/UK | 1/8" – 2" |
| NPT (US Pipe Tapered) | US-origin hydraulics + imported process | 1/8" – 2" |
| Taper Tap (1st) | STARTING the thread — 7-10 thread taper lead | Per size |
| Intermediate Tap (2nd) | Continuing thread — 3-5 thread taper | Most common single tap purchase |
| Plug Tap (3rd / Bottoming) | BLIND HOLES — finishes thread close to bottom | Per size |
| 3-Tap Set (Taper + Intermediate + Plug) | Full set for one size + thread form | Workshop standard |
Critical: For tap drill sizes see threading tap size chart. Use cutting fluid + tap wrench + back off ¼ turn every full turn to break chips. NEVER force a stuck tap — broken taps in steel are very difficult to remove. Brands: Sutton Tools, Bordo. Companion: all taps, threading, tap wrenches, tap + die sets.
The Three-Piece Tap Sequence
A full hand tap set works in three stages:
- Taper (1st) — 8-10 thread lead chamfer. Used to start the thread square and true. Easiest to turn through fresh material.
- Intermediate (2nd, "plug") — 3-5 thread lead. Continues the thread to working depth in through-holes. Default tap when only one is used.
- Bottoming (3rd) — 1-2 thread lead. Threads as close to the bottom of a blind hole as the tap geometry allows.
You don't always need the full set. Through-holes only need the taper or the intermediate. Blind holes typically take a taper to start and a bottoming to finish. Tough materials benefit from running all three.
Thread Forms Stocked
BSW, BSF, UNC, UNF and BA cover most imperial work seen in Australian workshops, mining, marine and restoration trades. For thread identification help, see our Metric vs Imperial Fasteners Guide. For tapping drill sizes, see the Tap Size Chart.
Tap Wrenches and Cutting Fluid
A hand tap is only as good as the tap wrench holding it square. Use a T-handle for small taps (up to about 6mm / 1/4") and a long bar-handle wrench for larger sizes. Cutting fluid matters more for hand tapping than machine tapping — it reduces friction, breaks chips and protects the tap edge. See the Cutting Fluids Guide for fluid selection by material.
Sutton or Goliath?
Sutton — Australian-made HSS, ground threads, the workshop standard. The T-series codes (T414, T446, T471 etc.) identify the thread form and finishing style.
Goliath — UK heritage brand, also HSS. Often available in sizes Sutton doesn't catalogue, including some left-hand and small BA threads.
Companion Collections
Other tap geometries: Imperial Straight Flute Taps, Imperial Spiral Point Taps (machine through-hole tapping), Imperial Spiral Flute Taps (machine blind-hole tapping), Imperial Thread Forming Taps (cold-forming, no chips), Imperial Machine Nut Taps. For the full range covering metric and imperial: Threading.
Common Questions
Do I need all three taps or just one? Through-holes — one tap (intermediate) is usually enough. Blind holes — start with a taper, finish with a bottoming. Hard or stainless material — use all three to spread the cutting load.
Can I use a hand tap in a machine? Yes — at low spindle speeds (50-100 RPM) with cutting fluid. For production tapping in a machine, spiral-flute or spiral-point taps are faster and clear chips better.
What's the smallest imperial hand tap I can use by hand? 4 BA or #4 UNC is about the smallest most operators can hand-tap reliably. Below that, use a sensitive tapping head in a drill press to keep the tap square.
Why is the tap not cutting? Common causes: hole too small, no cutting fluid, dull tap, off-square start, or wrong thread form. Check the tapping drill size in the Tap Size Chart.
If you need a specific size or thread form not showing online, call the Sydney team on (02) 9773 0122. We hold more than the website displays.