Thread Checker 40 Nut and Bolt Thread Gauge - Accurate Thread Finder

In this review the Thread Checker 40 Nut and Bolt Thread Gauge proves to be a practical, workshop-friendly tool for anyone who regularly deals with fasteners. The single biggest reason to buy is its reliable, CNC-machined sizing built to the Go & No-Go Class 2B ANSI Standard, which removes guesswork when matching nuts, bolts and screws. For hobbyists, mechanics and shop technicians who need quick, accurate identification of both metric and imperial threads, this gauge streamlines the process and reduces wasted time and mismatched parts.

Key Features

• Precision Sizing: CNC-machined to Go & No-Go Class 2B ANSI Standard for dependable identification of internal and external threads.
• Wide Coverage: Identifies 40 thread sizes covering Metric M2 x 0.4 to M16 x 2.0 and Imperial #2 - 56 to 5/8 - 18 Fine, so most common fasteners are included.
• Dual Thread Types: Each size has both a male and female thread fit, allowing checks of nuts, washers, bolts and screws with the same tool.
• Durable Construction: Machined from 6061 aluminum with an anodized finish and stainless steel studs for resilience in a busy shop environment.
• Built-in Rulers: Features a 15 cm and 6 in ruler on either edge for quick linear checks and measurements while identifying thread sizes.
• Mounting Options: Includes a hanging hole and four anti-slip silicon feet so it can be wall-mounted or set securely on a bench.

Who It's For

The Thread Checker is aimed at home mechanics, small machine shops, bicycle and motorcycle enthusiasts, and anyone who services equipment with a mix of metric and imperial fasteners. Its accurate, labeled slots and GO/NO-GO sizing make it especially useful when replacing hardware or sorting a mixed bin of nuts and bolts.

It is less suited to those who only occasionally need to identify a single size and prefer a disposable or purely visual chart; users who require specialized thread forms outside standard metric and imperial ranges should look to a more comprehensive gauge set.

Pros & Cons

Pros

• All-metal construction and laser-etched markings make it durable and easy to read after extended use.
• Covers both metric and imperial fasteners with 40 distinct sizes, reducing the need for multiple gauges.
• Versatile mounting options keep the gauge handy on a wall or stable on a workbench.
• Includes handy inch and centimeter rulers for quick measurements during tasks.

Cons

• Does not cover specialized or non-standard thread forms beyond common metric and imperial sizes, so advanced shops may still need additional gauges.

Specifications

Material	6061 aluminum with anodized finish
Thread Standard	Go & No-Go Class 2B ANSI Standard
Number of Sizes	40 sizes (20 metric, 20 imperial)
Metric Range	M2 x 0.4 to M16 x 2.0
Imperial Range	#2 - 56 Coarse to 5/8 - 18 Fine
Rulers	15 cm and 6 in on both sides
Mounting	Hanging hole and four anti-slip silicon feet

Our Verdict

The Thread Checker is a compact, well-made gauge that delivers accurate thread identification for most workshop needs. It is good value for anyone who regularly works with a mix of metric and imperial fasteners, offering durable construction, clear markings and practical mounting options that save time and reduce errors when fitting nuts and bolts.

Frequently Asked Questions

Does this gauge check both nuts and bolts?
Yes. Each size includes a male thread and a female thread so you can check nuts, washers, bolts and screws.

How accurate are the size markings?
The gauge is CNC-machined to Go & No-Go Class 2B ANSI Standard and uses laser-etched markings for reliable and repeatable sizing.

Can it be mounted on a wall?
Yes. It has a hanging hole for wall mounting and four anti-slip silicon feet for bench use.