Thread Gauges
High-precision thread gauges for accurate thread inspection. We manufacture plug gauges, ring gauges, and setting plugs for all standard thread forms including Metric, Unified, BSW, BSP, and NPT.
What are Thread Gauges?
Thread gauges are precision measuring instruments used to verify the accuracy of screw threads. They ensure that threaded components meet specified tolerances and will properly mate with their intended counterparts. Thread gauges are essential in manufacturing for quality control of bolts, nuts, screws, and threaded holes.
DSN Enterprises manufactures a comprehensive range of thread gauges including plug gauges for internal threads, ring gauges for external threads, and setting plugs for gauge calibration. Our gauges are manufactured to international standards and are available for all major thread forms used worldwide.
Thread Forms We Cover
Metric (ISO)
M1 to M100, coarse and fine pitch
Unified (UNC/UNF)
American standard threads
British Standard (BSW/BSF)
Whitworth and fine threads
British Pipe (BSP/BSPT)
Parallel and taper pipe threads
American Pipe (NPT/NPTF)
National pipe taper threads
Trapezoidal (Tr)
Power transmission threads
Our Thread Gauge Products
Comprehensive range of thread gauges for all standard thread forms and custom specifications.
Thread Plug Gauge
Metric, UNC, UNF, BSW, BSF, BSP & more
Precision thread plug gauges for accurate internal thread inspection. Available in GO and NO-GO configurations for quick verification of female threads in manufactured parts.
Key Features:
- GO and NO-GO members
- All standard thread forms
- High-precision thread profile
- Sub-zero treated for stability
- Hardness: 60 ± 2 HRC
Applications:
Thread Ring Gauge
Metric, UNC, UNF, BSW, BSF, BSP & more
Precision thread ring gauges for external thread inspection. Essential tools for verifying male threads on bolts, studs, and threaded components.
Key Features:
- GO and NO-GO configuration
- Adjustable ring gauges available
- Precision thread form
- Wear-resistant construction
- NABL calibration available
Applications:
Thread Setting Plug Gauge
All standard thread forms
Master gauges used for setting and calibrating thread ring gauges. Essential reference standards for maintaining accuracy of working gauges.
Key Features:
- Truncated thread profile
- Full form thread profile
- Calibrated to master standards
- Supplied with certificate
- Premium grade materials
Applications:
Taper Thread Gauges
NPT, NPTF, BSPT & API threads
Specialized gauges for inspecting tapered pipe threads. Critical for ensuring proper sealing in pipe connections for oil, gas, and fluid handling systems.
Key Features:
- NPT/NPTF thread forms
- BSPT thread forms
- Plug and ring configurations
- L1 gauge included
- API thread options
Applications:
Metric Thread Gauges
M1 to M100, Fine & Coarse Pitch
Complete range of metric thread gauges for both coarse and fine pitch threads. Manufactured to ISO standards for global compatibility.
Key Features:
- ISO metric thread profile
- Coarse pitch (standard)
- Fine pitch options
- Class 6g/6H tolerances
- Complete size range
Applications:
Unified Thread Gauges (UNC/UNF)
UNC, UNF, UNEF - All sizes
American standard unified thread gauges for inspection of UNC (coarse), UNF (fine), and UNEF (extra fine) threads widely used in aerospace and automotive industries.
Key Features:
- UNC coarse pitch
- UNF fine pitch
- UNEF extra fine pitch
- Class 2A/2B, 3A/3B
- MIL-SPEC compliant
Applications:
Understanding Thread Gauge Types
Thread Plug Gauges
Used to inspect internal threads (tapped holes). The GO member should enter freely, while the NO-GO member should not enter more than 2-3 turns.
- • GO member checks minimum material
- • NO-GO checks maximum material
- • Available for all thread forms
Thread Ring Gauges
Used to inspect external threads (bolts, studs). The GO ring should pass over the thread, while the NO-GO ring should not pass beyond 2-3 turns.
- • GO ring checks major diameter
- • NO-GO checks pitch diameter
- • Adjustable types available
Setting Plug Gauges
Master gauges used to set and verify thread ring gauges. Essential for maintaining calibration accuracy of working gauges.
- • Truncated for GO setting
- • Full form for NO-GO setting
- • Calibration certificates
Technical Specifications
| Material | OHNS (W) / Tungsten Carbide |
| Hardness | 60 ± 2 HRC |
| Treatment | Sub-Zero at -80°C |
| Thread Accuracy | As per IS/ISO/ANSI Standards |
| Surface Finish | Ground/Lapped Finish |
| Certification | NABL Certificate Available |
Standards Followed:
- • IS 6175 - ISO Metric Screw Threads
- • IS 4218 - ISO Metric Thread Tolerances
- • ANSI/ASME B1.2 - Unified Threads
- • BS 84 - BSW/BSF Threads
- • BS 21 / ISO 7-1 - Pipe Threads
- • API 5B / 7-2 - Oil Field Threads
Need Thread Gauges?
We manufacture thread gauges for all standard and special thread forms. Contact us for custom specifications, bulk orders, or technical support.