Roll Form Tap

 1/4-20 Thread forming tap |Roll Form Tap for Inch Thread

UNC thread form tap

Key Features of UNC Forming Tap

  • Chipless Roll Forming Structure Fluteless design produces zero swarf, completely solving blind hole and deep hole chip blockage problems. Clean threading with no thread scratching.
  • Higher Thread Strength Cold extrusion retains continuous metal grain flow. Formed UNC/UNF threads are 20%-30% stronger than cut threads, with better anti-loosening and fatigue resistance.
  • Ultra Low Breakage Rate Integrated solid body greatly improves rigidity and torsion resistance. Significantly reduce tap fracture during high-torque continuous tapping.
  • High Precision Inch Thread Standard Strictly comply with UNC (Coarse Thread) and UNF (Fine Thread) American standard, standard tolerance 2B, fully interchangeable with US standard fasteners.
  • Multiple Coating Options Uncoated / TiN / TiCN / AlTiN / DLC available. DLC for aluminum anti-sticking, AlTiN for stainless steel long-life tapping.
  • Longer Tool Life & Lower Cost2–5 times service life than traditional inch cutting taps, reducing downtime and tool replacement frequency for mass production.

Machinable Materials

  • Non-ferrous Metals: Aluminum alloy, brass, copper, zinc die-cast alloy, magnesium alloy
  • Carbon Steel: Mild steel, medium carbon steel, low-carbon ductile steel
  • Stainless Steel: 201, 304, 316, 316L, 430 stainless steel
  • Alloy Steel: 40Cr, SCM435, 42CrMo (≤35HRC tempered alloy steel)

Application Scenarios

  • Automotive & Motorcycle Parts Inch thread machining for auto fasteners, hydraulic parts, brake system components and chassis accessories.
  • New Energy Industry Precision UNC/UNF threading for battery components, energy storage structural parts and aluminum shell fittings.
  • 3C & Precision Hardware High-precision inch thread tapping for communication equipment, instrumentation and precision electronic assemblies.
  • Mechanical & Mold Manufacturing Blind hole, deep hole and thick plate inch thread processing for molds, fixtures and mechanical equipment.
  • Mass Automated CNC Production Stable performance for long-time unmanned machining, ideal for factories pursuing high efficiency and low defective rate.

UNC / UNF Forming Tap Full Specification Table (Standard Dimension)

Standard: ANSI/ASME B1.1 | Tolerance: 2B | Material: HSS-E / HSS-PM Optional
Thread Size
Thread Type
TPI (Threads Per Inch)
Overall Length (mm)
Shank Diameter (mm)
Thread Length (mm)
Square Size (mm)
#4-40
UNC
40
48
3.5
9
2.7
#6-32
UNC
32
48
3.5
10
2.7
#8-32
UNC
32
50
4.0
11
3.0
#10-24
UNC
24
53
4.5
12
3.4
1/4-20
UNC
20
58
6.0
14
4.9
5/16-18
UNC
18
66
8.0
16
6.2
3/8-16
UNC
16
72
10.0
18
8.0

Recommended Pre-Drill Size Chart for UNC / UNF Forming Tap

Optimized hole size for roll forming process, ensure standard thread fill rate and low tapping torque
Thread Size
Thread Type
TPI
Pre-Drill Size (mm)
#4-40
UNC
40
2.30
#6-32
UNC
32
2.85
#8-32
UNC
32
3.45
#10-24
UNC
24
4.05
1/4-20
UNC
20
5.10
5/16-18
UNC
18
6.60
3/8-16
UNC
16
8.00