Resources
- Blog Tip
-
Hardness Testing
-
Bibliography
-
International
-
Hardness Testing
-
Rockwell
- Introduction
- Rockwell Hardness Test
- Annex C
- Annex B
- Annex A:Applied Force Effect
- Status of Rockwell Hardness Standardization in the Year 2000
- Uncertainty
- Measurement Error
- Traceability, Error, and Uncertainty
- Measurement Locations
- Verify Machine Measurement Performance
- Reduce Machine Component Operating Errors
- Reducing Measurement Differences and Errors
- Daily Verification
- Monitoring Test Machine Performance
- Correcting Measurement Biases
- Indirect Verification
- Direct Verification
- Verifications of Rockwell Hardness Machines
- Use of Reference Test Block Standards
- Secondary Reference Test Blocks
- Primary Reference Test Blocks
- Reference Test Block Standards
- Hardness Measurement
- Rockwell Hardness Testing Machine
- Test surface preparation
- Rockwell Hardness Test Choosing Scales
- Rockwell Hardness Test Procedure
- Rockwell Hardness Test Standards
- Rockwell Hardness Test Numbers
- Rockwell Hardness Test Scales
- Rockwell Hardness Test Principle
- Rockwell Hardness Test Significance
-
Bibliography
-
Helpful Industry Resources Publications
-
Precision Gages
- Precision Manufacturing
- Precision Machining Technology 2nd Edition
- Interpretation of Geometric Dimensioning and Tolerancing 3rd Edition
- Fastener Black Book
- Engineers Precision Data Pocket Reference Edition
- Machinery's Handbook, Pocket Companion 30th Edition
- Engineers Black Book
- Handbook of Dimensional Measurement 5th Edition
- Machinery's Handbook, 30th Edition, Large Print and Machinist Calc Pro 2 Combo
- Inspection and Gaging, Sixth Edition
- Blueprint Reading Basics 3rd Edition
-
Calibration
- Computational Surface and Roundness Metrology
- Industrial Metrology: Surfaces and Roundness
- Engineering Metrology and Measurements
- Handbook of Metrology and Testing
- Basic Metrology for ISO 9000 Certification
- The Metrology Handbook, 2nd Edition (With CD-ROM) Hardcover – 2015
- Machine Tool Metrology: An Industrial Handbook 1st ed. 2016 Edition
- Fundamentals of Dimensional Metrology 6th Edition
- An Introduction to Measuration and Calibration
-
Hardness Testing
- Fully Automatic Digital Rockwell Hardness Tester
- Testing of Materials
- The Hardness of Metals
- Testing the Hardness and Durability of Metals (Classic Reprint)
- A Study of the Relation Between the Brinell Hardness and the Grain Size of Annealed Carbon Steels
- Hardness Testing 2nd Edition
- On Depth Sensing Indentation of Materials: Mechanical Characterization
- Heat-Treatment of Steel
- Hardness Testing: Principles and Applications First Edition
-
Precision Gages
-
Precision Gages
-
Straight Pipe Threads Table Chart ANSI
-
Useful Resources
-
Gage Calibration FAQs
-
Fixed Limit Gages (Plugs and Rings) Resources
-
Thread Plug Gage
- National Standard Taper Pipe Threads Size NPT Chart
- External ACME Thread General Purpose Size Chart
- Internal ACME Thread General Purpose Size Chart
- Pg thread profile chart
- Standard Pitch Diameter Chart
- Standard Pitch Diameter Chart
- Fixed Limit Gages (Plugs and Rings) Resources
- Charts ANSI-Thread Gage Chart
- Thread Ring Gage
-
Air Gages
- Cylindrical Gages
-
British Thread Gages
-
Straight Pipe Threads Table Chart ANSI
-
Taps & Dies
-
Tap Drill Sizes for Metric M-Profile Screw Threads
-
Tap Drill Sizes for Unified Inch Screw Threads
-
Tapping Hints
-
Selecting Taps
-
Wear
-
Torn or Rough Thread
-
Undersize Pitch Diameter
-
Undersize Internal Diameter
-
Oversize Pitch Diameter
-
Chipping
-
Chattering on Tapped Thread
-
Breakage
-
USCTI Table 311 - Standard Pipe Dimensions, Straight & Taper - Ground Thread
-
USCTI Table 303 - Special Fine Pitch Taps, Short Series - Ground
-
USCTI Table 302A - Optional Neck & Shortened Thread Length Tap
-
USCTI Table 302 - Standard Tap Dimensions - Ground Thread
-
USCTI Table 301B
-
Tap Drill Sizes for Metric M-Profile Screw Threads
Cylindrical Reversible Plug Gages
Introduction
Reversible cylindrical plug gages, also known as reversible plain plug gages, are used to inspect a drilling opening. When one tip of a reversible gauge gets broken or worn, the gauge member may be flipped, giving outstanding value (basically two gauge components for the cost of one). With many use cases for WESTport’s cylindrical reversible plug gages you are now able to get a tool with multiple uses.
Read on to learn more about WESTport's Trilock Cylindrical Reversible Plug Gages.
Cylindrical Reversible Plug Gages Specifications
The widths are ring-lapped to fit and carefully finished giving for improved precision and assuring optimal gage wearability. Equipped with NOGO and GO members in different classes, like Class Z, Y, X, XX, and XXX according to ANSI requirements. The aluminum gauge chambers are anodized red (NO GO) and green (GO) allowing for simple differentiation. Except as specifically indicated, the gage maker's margins will be imposed extra on the GO component and negative for the NO GO component.
Available in carbide, chrome, and steel, the WESTport's cylindrical reversible plug gauges are made to last. Steel gauges are composed of high-grade 52100 tool steel that has been hardened to Rockwell C60-64 and cold annealed to minimize size and shape variations, resulting in an unusually extended gauge life. Gages measure 2.0" long. Special length gauges up to 6.0" in dimension are supplied. All gauges are polished, sanded, and lapped to a surface polish of 5 micro inches or greater. From .015" to 1.0100", reversible cylindrical steel and chrome plug gauges are provided. Carbide plug gauges range in size from .040" to.761".
Cylindrical Reversible Plug Gages Special Features
Special characteristics like chamfers, radius, pilots, air flats, and depth notches are quoted on a case-by-case basis. WESTport Gage includes a complimentary Accuracy Certificate traceable to the National Institute of Standards and Technology (NIST) with every gauge.
These Gages are carefully lapped for maximum finish and accuracy and are kept to specification along their full length, allowing you to utilize either endpoint of the gauge. WESTport's cylindrical reversible plug gauges come in inch or metric sizes with carbide, chrome, and steel finishes. Custom gages are made and simply advise the dimension in inches or metric, the tolerance grade, and the tolerance applicability – Not Go (minus) or Go (plus), or Master (bilateral or split). Individual members do not come with handles. If a handle is necessary, please indicate.
At no extra charge, the tolerance, size, tolerance, and instrument number are securely inscribed on the grip. All specifications are available – please contact 1-888-876-8587 and a WESTport specialist would gladly generate an estimate for you.
Conclusion
Since 1989, the WESTport team has been providing excellent quality Cylindrical Reversible Plug Gages all around the world. We are devoted to consistently improving our goods, processes, and services to preserve our reputation as a dominant force in our market by putting our customers' interests first. We are also an ISO 9001, ISO 6508, ISO 6506, and ISO/IEC 17025 recognized manufacturer that provides "Quality you can Trust" to over 125 countries.
© 2025, RF for WESTport Corporation. All rights reserved. Unauthorized use is prohibited.

Resources
- Blog Tip
-
Hardness Testing
-
Bibliography
-
International
-
Hardness Testing
-
Rockwell
- Introduction
- Rockwell Hardness Test
- Annex C
- Annex B
- Annex A:Applied Force Effect
- Status of Rockwell Hardness Standardization in the Year 2000
- Uncertainty
- Measurement Error
- Traceability, Error, and Uncertainty
- Measurement Locations
- Verify Machine Measurement Performance
- Reduce Machine Component Operating Errors
- Reducing Measurement Differences and Errors
- Daily Verification
- Monitoring Test Machine Performance
- Correcting Measurement Biases
- Indirect Verification
- Direct Verification
- Verifications of Rockwell Hardness Machines
- Use of Reference Test Block Standards
- Secondary Reference Test Blocks
- Primary Reference Test Blocks
- Reference Test Block Standards
- Hardness Measurement
- Rockwell Hardness Testing Machine
- Test surface preparation
- Rockwell Hardness Test Choosing Scales
- Rockwell Hardness Test Procedure
- Rockwell Hardness Test Standards
- Rockwell Hardness Test Numbers
- Rockwell Hardness Test Scales
- Rockwell Hardness Test Principle
- Rockwell Hardness Test Significance
-
Bibliography
-
Helpful Industry Resources Publications
-
Precision Gages
- Precision Manufacturing
- Precision Machining Technology 2nd Edition
- Interpretation of Geometric Dimensioning and Tolerancing 3rd Edition
- Fastener Black Book
- Engineers Precision Data Pocket Reference Edition
- Machinery's Handbook, Pocket Companion 30th Edition
- Engineers Black Book
- Handbook of Dimensional Measurement 5th Edition
- Machinery's Handbook, 30th Edition, Large Print and Machinist Calc Pro 2 Combo
- Inspection and Gaging, Sixth Edition
- Blueprint Reading Basics 3rd Edition
-
Calibration
- Computational Surface and Roundness Metrology
- Industrial Metrology: Surfaces and Roundness
- Engineering Metrology and Measurements
- Handbook of Metrology and Testing
- Basic Metrology for ISO 9000 Certification
- The Metrology Handbook, 2nd Edition (With CD-ROM) Hardcover – 2015
- Machine Tool Metrology: An Industrial Handbook 1st ed. 2016 Edition
- Fundamentals of Dimensional Metrology 6th Edition
- An Introduction to Measuration and Calibration
-
Hardness Testing
- Fully Automatic Digital Rockwell Hardness Tester
- Testing of Materials
- The Hardness of Metals
- Testing the Hardness and Durability of Metals (Classic Reprint)
- A Study of the Relation Between the Brinell Hardness and the Grain Size of Annealed Carbon Steels
- Hardness Testing 2nd Edition
- On Depth Sensing Indentation of Materials: Mechanical Characterization
- Heat-Treatment of Steel
- Hardness Testing: Principles and Applications First Edition
-
Precision Gages
-
Precision Gages
-
Straight Pipe Threads Table Chart ANSI
-
Useful Resources
-
Gage Calibration FAQs
-
Fixed Limit Gages (Plugs and Rings) Resources
-
Thread Plug Gage
- National Standard Taper Pipe Threads Size NPT Chart
- External ACME Thread General Purpose Size Chart
- Internal ACME Thread General Purpose Size Chart
- Pg thread profile chart
- Standard Pitch Diameter Chart
- Standard Pitch Diameter Chart
- Fixed Limit Gages (Plugs and Rings) Resources
- Charts ANSI-Thread Gage Chart
- Thread Ring Gage
-
Air Gages
- Cylindrical Gages
-
British Thread Gages
-
Straight Pipe Threads Table Chart ANSI
-
Taps & Dies
-
Tap Drill Sizes for Metric M-Profile Screw Threads
-
Tap Drill Sizes for Unified Inch Screw Threads
-
Tapping Hints
-
Selecting Taps
-
Wear
-
Torn or Rough Thread
-
Undersize Pitch Diameter
-
Undersize Internal Diameter
-
Oversize Pitch Diameter
-
Chipping
-
Chattering on Tapped Thread
-
Breakage
-
USCTI Table 311 - Standard Pipe Dimensions, Straight & Taper - Ground Thread
-
USCTI Table 303 - Special Fine Pitch Taps, Short Series - Ground
-
USCTI Table 302A - Optional Neck & Shortened Thread Length Tap
-
USCTI Table 302 - Standard Tap Dimensions - Ground Thread
-
USCTI Table 301B
-
Tap Drill Sizes for Metric M-Profile Screw Threads