Precision Thread Plug Gauge Tol. 2B Unified coarse STI-Thread - UNC 1/4 x 20

• Inspect internal threads during setup, in process checks, or final inspection.
• Use it for acceptance decisions on threaded holes before assembly or coating steps.
• Apply the gauge by hand to evaluate fit and detect damage such as burrs or dents.
• Process: manual driving or assisted driving depending on your holder and machine setup
• Use: thread cutting, re tapping, and thread cleaning depending on condition

Note For consistent results, deburr the entry and keep the cutting area clean during use.

• Fast pass fail decision without complex measurement equipment
• Supports stable process control in serial production and incoming inspection
• Helps identify handling damage such as burrs, dents, or thread pull out
• Reduces assembly issues by filtering non conforming threads early

• Not suitable for determining the exact deviation of thread geometry; it is a limit check.
• Requires clean threads and careful hand feel; forcing can damage the gauge and the part.

1. Clean the threaded hole and remove oil, chips, and burrs from the entry.
2. Visually check the thread for dents, plating build up, or deformation.
3. Identify the GO and NO GO sides when the gauge has separate ends.
4. Insert the GO side by hand and turn with light finger force until it seats or stops.
5. Try the NO GO side by hand and stop as soon as resistance increases.
6. If the feel is inconsistent, clean again and repeat the check with the same handling.
7. Record the result and protect the gauge with a light corrosion protection film after use.

• 1 piece Precision Thread Plug Gauge Tol. 2B Unified coarse STI-Thread - UNC 1/4 x 20

• Type: Thread plug gauge for internal threads
• Tolerance: 2B
• Thread system: UNC

How do you use this gauge without damaging the thread?

Clean the thread first and apply the gauge by hand only. Stop at first abnormal resistance and investigate contamination or burrs before you decide on acceptance.

What does the designation UNC 1/4 x 20 tell you?

It states the exact thread form and size that the gauge is made for, including pitch information when it is part of the designation. Use only on matching thread designations.

What does tolerance 2B mean in practice?

It indicates the tolerance zone that the gauge is manufactured for. Use the gauge together with the correct drawing and standard so the acceptance decision matches your specification.

Where can you find catalog information for this product family?

Use the product catalog for overview tables and selection context. VG 23 catalog as PDF

How do you handle borderline results?

Repeat the check after cleaning and keep handling consistent. If the feel changes between checks, inspect the thread for damage, plating build up, or deformation.

How do you store and protect the gauge?

Keep it clean and lightly protected against corrosion. Store it in a protective case and avoid contact with other hardened tools to prevent nicks.