Understanding GO Gauge Failures in Threaded Fasteners
Thread inspection using GO/NO-GO gauges is a standard quality verification method for threaded fasteners. However, buyers and inspectors occasionally encounter situations where a GO gauge fails to pass — even on products that appear dimensionally correct. At FULLERKREG, we regularly address this question, and the root cause typically falls into one of two categories.
Cause 1: Thread Surface Damage (Bruising)
300-series austenitic stainless steel — the material used in the majority of our fasteners — is relatively soft compared to carbon steel. During production, handling, and transportation, minor surface bruising or nicks on the thread flanks can occur. This is a known characteristic of the material and is recognized across the industry.
According to GB/T 5779.1-2000 (the Chinese national standard for fastener surface discontinuities), minor damage is defined and permitted within specified limits:
- Definition: Damage refers to any scratch, nick, or gouge on the surface of a screw thread or bolt, caused by external contact during production or transit.
- Visual appearance: Irregular in shape, with no defined orientation — making it difficult to distinguish from external influences.
- Acceptance limit: Minor damage is acceptable provided it does not impair function. Specifically, at the thread crest and within the first three thread pitches, damage must not prevent the GO gauge from passing when applied with a torque not exceeding 0.001d³ N·m (where d = nominal thread diameter in mm).
In practice: if a GO gauge passes with slight manual force — within the torque limit defined by the standard — the product is considered conforming. This is not a defect.
Cause 2: Gauge Variation Between Manufacturers or Age
A second common cause of GO gauge failures is gauge-to-gauge variation, which can arise from two scenarios:
a) Different Gauge Manufacturers
Gauges produced by different manufacturers may have slightly different tolerance interpretations within the same nominal specification. It is possible for a batch of fasteners to pass Manufacturer A's GO gauge but fail Manufacturer B's — even when both gauges are nominally compliant. This is a gauge calibration and tolerance stack-up issue, not a product defect.
b) New vs. Worn Gauges
A new gauge is manufactured to the tightest end of its tolerance band, while a worn (but still in-service) gauge has expanded slightly toward the go/no-go boundary. As a result, a new gauge may reject parts that a worn-but-valid gauge accepts. If you encounter this situation, we recommend contacting FULLERKREG — we can provide reference gauges for cross-verification.
The Standard for Batch Acceptance: ASME B1.3M
For international buyers, the applicable standard for thread gaging system acceptability is ASME B1.3M (Screw Thread Gaging Systems for Dimensional Acceptability). Key provisions include:
- A threaded product is acceptable when each thread characteristic specified in the designated gaging system is found acceptable.
- Within each gaging system, a choice of gauges is specified for each characteristic. Acceptance by any one gauge specified for a characteristic shall be the criterion for acceptance of that characteristic.
In practical terms: if a batch passes with one conforming GO gauge — even if it fails another — the batch is considered acceptable under ASME B1.3M. This principle protects buyers and suppliers from gauge-induced false rejections.
How to Resolve a GO Gauge Dispute
- Minor thread damage within standard limits: Apply the GB/T 5779.1-2000 torque criterion. If the gauge passes with the specified torque, the product is conforming.
- Gauge manufacturer or age discrepancy: Contact FULLERKREG customer service. We can arrange cross-verification using our reference gauges and provide documentation to support acceptance decisions.
- Systematic failure across the entire batch: This may indicate a genuine dimensional issue. Please contact us immediately with your order details for investigation and resolution.
FULLERKREG Quality Assurance
All FULLERKREG fasteners are inspected to DIN, ISO, and GB standards prior to shipment. Thread gauging is performed using calibrated GO/NO-GO gauges traceable to national standards. For critical applications, we offer third-party inspection reports and material certifications upon request.
Contact FULLERKREG for technical support, gauge cross-verification, or bulk fastener sourcing.