Buy Imperial Thread Forming Taps Online in Australia
Thread forming taps — also called "roll taps" or "fluteless taps" — cold-form threads instead of cutting them. The tap displaces metal sideways into the thread profile, work-hardening the surface and producing a stronger thread than a conventional cutting tap. No chips are produced.
AIMS stocks Sutton imperial thread forming taps across the popular BSW, UNC and UNF sizes.
Imperial Thread Forming Tap Selection — Quick Reference (Roll Taps / Fluteless)
Thread forming taps ("roll taps" / "fluteless taps") = COLD-FORM threads instead of cutting. Tap DISPLACES metal sideways into thread profile, WORK-HARDENING the surface = STRONGER thread than conventional cutting taps. No chips produced.
| Imperial Forming Tap | Best For |
|---|---|
| UNC Coarse (1/4 to 1") | Standard imperial coarse — workshop common |
| UNF Fine | Fine pitch imperial threading |
| BSW (Whitworth) | Older AU + UK equipment |
| HSS Standard | Aluminium + mild steel + copper |
| HSS Cobalt | Stainless + tougher materials |
| TiN-Coated | Extended life + production |
| With Lubricant Channel (Grooved) | Reduced friction + better forming |
Critical: Forming taps need PILOT HOLE LARGER than cutting tap (typical +5-10% on hole size). Material MUST be DUCTILE — aluminium + copper + mild steel = ideal; cast iron + brittle materials = NO (will crack). NO CHIPS = clean process suitable for blind holes + can't use cutting fluid (use forming lube). Resulting thread STRONGER + better tolerance than cut thread. Brands: Sutton Tools, Bordo. Companion: threading, metric thread forming taps, threading tap chart.
Why Use a Forming Tap
- No chips — Critical for blind holes, hydraulic components and aerospace work where chip contamination is unacceptable.
- Stronger threads — Cold-working raises tensile strength of the thread flanks by 30-50%. The grain structure flows around the thread profile rather than being cut through.
- Longer tap life — No cutting edges to wear or chip. A forming tap can outlast a cutting tap by 5-10x in ductile materials.
- Smaller tapping drill — Forming taps need a slightly larger pilot hole than cutting taps. Specific drill sizes are stamped on the tap.
When Forming Taps Won't Work
Forming taps require a ductile material — they displace metal, not remove it. Don't use them in cast iron (brittle, no plastic flow), hardened steel above ~30 HRC, or composite materials. They work brilliantly in aluminium, copper, brass, mild steel up to ~30 HRC, soft stainless and many soft alloys.
Lubrication Matters
Forming taps generate significant friction and heat. Cutting fluid is essential — use a forming-specific tapping paste or a sulphurised oil. Dry-tapping a forming tap will weld it into the workpiece. See the Cutting Fluids Guide for material-specific fluid choices.
Sister Tap Collections
Conventional cutting tap collections: Imperial Hand Taps, Imperial Straight Flute Taps, Imperial Spiral Point Taps, Imperial Spiral Flute Taps, Imperial Machine Nut Taps. Parent: Threading.
Common Questions
Tapping drill size for a forming tap? Larger than for a cutting tap of the same thread — typically 5-10% larger. Sutton stamps the recommended hole size on the tap shank. Don't use the standard Tap Size Chart values — you'll strip the thread.
Why is the formed thread shiny? The cold-working process burnishes the thread surface. The flanks are smoother than a cut thread and have a slight work-hardened layer.
Can I use a forming tap on stainless? Soft stainless (304, 316) yes, with the right fluid. Hardened or high-tensile stainless will resist forming and damage the tap.
Need help selecting forming or cutting taps for a job? Call (02) 9773 0122.
People Also Ask — Imperial Thread Forming Taps
Q: Why does a thread-forming tap need a larger pilot hole than a cutting tap of the same thread size?
A forming tap displaces metal sideways into the thread profile rather than removing it, so it needs a pilot hole roughly 5-10% larger than a cutting tap would use for the same thread — using a cutting-tap-sized hole doesn't leave room for the displaced material and will overload the tap.
Q: Why can't thread-forming taps be used in cast iron or hardened steel?
Forming taps rely on the material flowing plastically around the thread profile, which needs a ductile material — aluminium, copper, brass and mild steel up to around 30 HRC all form well, while brittle materials like cast iron have no plastic flow and will crack instead of forming a clean thread.
Q: How much longer does a thread-forming tap typically last compared to a cutting tap in the same material?
A forming tap can outlast a cutting tap by 5-10 times in ductile materials, since it has no cutting edges to wear down or chip — the tap's life is limited by fatigue and wear on the forming lobes rather than edge dulling.
Q: Why does lubrication matter even more with a thread-forming tap than with a conventional cutting tap?
Forming taps generate significant friction and heat from displacing metal rather than cutting it, so a forming-specific tapping paste or sulphurised oil is essential — running one dry can weld the tap directly into the workpiece.
Q: What imperial thread sizes does AIMS stock in thread forming taps?
The popular BSW, UNC and UNF sizes are stocked in Sutton thread forming taps, covering the imperial thread forms most commonly asked for in ductile-material forming applications.