Technical Information

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Thread Check Inc. Video Technical Series
Thread Check Inc., presents the Technical Video Series 101 for gaging and measuring.
How to Use Thread Ring Gages

Go and no go thread ring gages are very easy to use. The user must first select the correct size thread ring gages for the corresponding external threaded product. This is obviously critical but sometimes difficult as drawings and specification requirements are frequently missing, incomplete, or incorrect. The user of the thread ring gages should ensure that the correct major diameter, TPI/pitch, Class of fit, and any special pitch diameters are clearly specified. The user should also confirm that the gages conform to the proper national or international standard.

How to Use Thread Plug Gages

Go and no go thread plug gages are very easy to use. The user must first select the correct size thread plug gages for the corresponding externally threaded product. Thread plug gages should be clearly labeled on the handle but also on the gage members when possible. This is obviously critical but sometimes difficult as drawings and specification requirements are frequently missing, incomplete, or incorrect. The user of the thread plug gages should ensure that the correct major diameter, TPI/pitch, Class of fit, and any special pitch diameters are clearly specified.

Calibration Procedures for Thread Ring Gages

Thread Check's Calibration procedure sheet provides step by step detailed instruction for properly setting and calibrating thread ring gages by use of AGD standard truncated setting plug gages. The setting of thread ring gages is specific to the particular set plug that the ring is set to. It is common for ring gages to have a different feel on another setting plug of the identical size. It is recommended that a set plug be readily available in house to inspect gages being heavily used or for gages that have been dropped or impacted. For high volume inspection, it is good practice to have a new backup gage for comparison and reference inspection against the heavily used gage. Go thread ring gages can be set slightly snugger than No Go thread ring gages particularly when shipping components to customers for incoming inspection and assembly. Keep gages lubricated and handle with care for longer gage life. Spinning ring gages onto parts or forcing gages past burrs will reduce gage life.

Thread Gage Maintenance and Storage

Carrying out proper maintenance and storage procedures will ensure longer life for thread gauges. Neglecting to clean thread gages after every use and inspecting them for burrs, grit and part chips may result in unnecessary wear and scratches on the gage flanks and major and minor diameters of thread gauges. Always check that the gage recalibration date is current.

Rules For Determing How Many Turns A No Go ( Lo ) Ring Gage Can Enter A Part

A NoGo or (Lo) thread ring gage inspects the NoGo or (Lo) functional diameter limit of product external thread. The NoGo thread ring gage, when properly set to its respective calibrated thread setting-plug, represents the NoGo (Lo) functional diameter limit of the product external thread. NoGo (Lo) thread ring gages must be set to the applicable truncated or Hi-Lo setting plugs.

Proper Care And Usage Of Gages

Part dimensions to be gaged should be cleaned and burr free to prevent gaging interference. Grit and part chips which become lodged in thread gages will create scratches and wear on the flanks of threads and on the outside and inside diameters of cylindrical plain gages. Various materials such as aluminum and castings are extremely abrasive and will tend to wear out gages more quickly than other types of materials. Finer pitch and smaller diameter thread gages tend to wear quicker than larger and coarser pitch gages and have less gage tolerance as well. Regarding thread gages, it only takes a small amount of wear to have a significant effect on the pitch diameter. The wear on each flank angle is multiplied by almost 4 times to determine the total impact of wear on the pitch diameter. 50 microinches or 1 micron of wear per thread flank will impact the measured size by .0002” which can be the total tolerance of many thread gages.

What is the difference between UNR vs. UN Screw Threads?

The UNR thread form and UN thread form are identical except that the roots of the external threads are rounded with a radius of curvature between 0.108 and 0.144 times the pitch. The rounded root improves fatigue strength compared to the UN thread form.

UNR Screw Thread Form

The UNR thread form applies only to external threads. Its design form is the same as that of the external UN thread except that the root is required to be rounded. UNR threads are applied most often to high volume commercial fastener threads produced by rolling

No Go Gaging Per ANSI/ASME B1.2-1983 An American National Standard
A NoGo or Lo thread ring gage inspects the NoGo or Lo functional diameter limit of product external thread. The NoGo thread ring gage, when properly set to its respective calibrated thread setting-plug, represents the NoGo (Lo) functional diameter limit of the product external thread. NoGo (Lo) thread ring gages must be set to the applicable truncated or Hi-Lo setting plugs.
What's The “J” In UNJ Screw Threads?

UNJ, UNJC, UNJF and UNJEF threads are almost identical to UN, UNC, UNF, and UNEF threads except that the external J thread has a much larger root radius than the standard UN threads and inspection must be performed on this element. The Special UNJ threads are designated by the nomenclature UNJS. J screw threads feature a root radius which improves the tensile stress area of the fastener and helps to reduce the stress concentration factor in the thread thus making the thread stronger. Additionally, the requirement for high strength is achieved with 3A and 3B classes of fit. All pitch diameters and tolerances are based on the Unified Inch Standard.


The J series thread is defined in specification ANSI/ASME SAE AS8879 (formerly MIL-S-8879) and in ANSI/ASME B1.15.

Terms Relating to Screw Threads and Gages

Thread Plug Gage is a complete internal thread gage of either single or double-end type, comprising handle and threaded gaging member or members, with suitable locking means.

Basic Screw Thread Designations

External and internal thread diagrams illustrate basic thread geometry. This technical sheet illustrates proper thread nomenclature and terminology for screw threads.

Standard Inch Pitch Diameters

Thread Check, Inc. offers basic, 2B, 3B, 2A, & 3A pitch diameter dimensions in chart form. Pitch diameters are the most important characteristic because it reflects the widest spectrum of possible defects in a thread.

Large Diameter Thread Inspection with Gagemaker

Purchasing large thread gages over 8.00 inches can be expensive or cost prohibitive. Even with smaller diameters, the Gagemaker systems can play a critical role in conjunction with fixed limit thread plug and ring gages. It’s always better to have an actual measured value when controlling dimensions as opposed to an attribute Go or NoGo qualification.

Metric Pitch Diameters

Thread Check, Inc. offers 6H and 6g metric pitch diameters for thread gages. Pitch diameters are the most important characteristic because it reflects the widest spectrum of possible defects in a thread. Pitch diameters can be accurately measured by use of the 3-wire method.

ANSI and International Thread Series Designations

Thread Check, Inc. manufactures gages to the following ANSI Thread Series Designations and international standards. All Unified threads including – UN, UNC, UNF, UNEF, UNS, UNJ, UNJC, UNJF, UNJEF, UNR, UNRC, UNRF, and UNREF. NC5, NC5HF, NC5CSF, NC5ONF, NC5IF, M, MJ, MJS, UNM, NPT, NPTF, F-PTF, PTF-SAE Short, PTF-SPL Short, PTF-SPL Extra Short, SPL-PTF, ANPT, NPSL, NPSM, NPSC, NPSF, NPSI, NH, NPSH, NFPA, NHR, NGT, NGO, NGS, SGT, R, Rc, Rp, G Series, BSW, BA, ACME –C, ACME –G, Stub ACME, BUTT, PUSH BUTT, AMO, AWWA, DIN, JIS, and ISO standards.

Thread Systems

The two major screw thread systems used today are ISO metric and the Unified thread standard. The advantages of using coarse threads and fine threads are covered in this document. A metric tolerance class 6g ring and 6H plug is suitable for use where a Unified class 2A Ring and 2B thread plug was previously used on a thread for comparison basis.

Adjustable Thread Ring Gage Calibration: How Accurate Is It?

While a new AGD - American Gage Design adjustable thread ring gage is initially calibrated to a master setting plug gage, the setting can be slightly altered during the transport from manufacturer to end user. This can result from a variety of factors, ranging from a dropped adjustable ring gage to exposure to radical changes in temperature during the shipping process.

Checking the Pitch Diameter of a Thread with a “No Go” Gage

The pitch diameter of a thread is the most important characteristic because it reflects the widest spectrum of possible defects in a threaded part or gage.

Calculating Pre Plate Screw Threads & Gages

It is important to understand how various plating affects manufactured parts featuring internal and external threads. All too often component parts are manufactured without taking into account the correct plating requirements. This results in rejection in final and incoming inspection or even in the field resulting in a recall. Either way proves to be very costly and time consuming.

Custom Threads - Terms & Definitions

Blunt Point – The removal of a male center point from threads smaller than #6(M4). This does not allow the gage to be face ground to within .5P. This is not a Blunt Start.

STI, Thread Ring Gages and Setplug Gages – Terms and Definitions

STI - Screw Thread Insert or Heli-Coil are trade names synonymous with STI threads. STI threads are used to repair stripped or poorly threaded holes.

Southern Style AGD Comparison

The Southern Adjustable Style Thread Ring Gage features an adjustment mechanism that maintains the roundness integrity of the gage throughout its use.

A Primer in Master Ring Philosophy: AGD vs. DIN Style
In today's manufacturing environment most people are comfortable working to the industrial standards that are applicable to their region. In the US, the standards might originate from any one of several groups with acronym names such as ANSI, ASME, AGMA, or other, depending on what products are being manufactured.
Unified Miniature Screw Threads per ASME B1.10M 2004

Dimensional product data and tables for Unified Miniature Screw Threads per ASME B1.10M 2004.

British Thread Gages

British thread gages provided by Thread Check Inc. as well as plug & ring gages manufactured to the latest BS and ISO specifications. Thread Check, Inc. supplies full form ISO 228 - 2 ( BS2779 ) Go/No Go thread British plug and ring gages.

Thread Profile Gages

The TP Series of Tapered Thread Profile Gages are manufactured to tolerances of +.0002”, using EDM technology. These precision gages are ideal for quickly identifying each of the different tapered thread forms named in the API Std. 5B and Specification 7. Thread profile gages can also be used to perform a visual inspection of a thread form for detecting chipped inserts, stretched threads, wide first threads, or rolled over threads. Special profiles are available and quoted upon request.

Profile Gages Thread Profile, TP Series

The TP Series of Thread Profile Gages are manufactured to tolerances of ±.0002" using EDM technology. These precision gages are ideal for quickly identifying each of the different thread forms named in the API Std. 5B and Specification 7.

Profile Gages Tapered Thread Profile

The TP/TP-JSS Series of Tapered Thread Profile Gages are manufactured to tolerances of +/-.0002 deg., using EDM technology. There precision gages are ideal for quickly identifying each of the different tapered thread forms named in the API Std. 5B and Specification 7.

Fixed Limit Thread Gages

A Go thread plug gage inspects the minimum major diameter and the minimum pitch diameter size in a threaded part. The NoGo thread plug gage inspects to ensure the threaded hole does not exceed the maximum pitch diameter size in a threaded part.

3 Wire Thread Measuring Systems

The traditional three-wire method is the most accurate method of measuring the effective or pitch diameter of an external screw thread. Unfortunately in the past, holding and correctly positioning three wires against a thread while simultaneously taking an accurate measurement had been an extremely difficult task. Now, Thread Check's 3-Wire Thread Measuring System provides a simple and precise way for determining the pitch diameter for threaded parts and thread plug gages. The system enhances Repeatability and Reproducibility ( R & R ) and reduces measurement time to a fraction of the time normally taken using the traditional three-wire method.

The Three Wire Method Of Measuring Pitch Diameter

The accurate measurement of thread pitch diameter, which may be perfect as to form and lead, presents certain difficulties which result in some uncertainty as to its true value. The adoption of a standard uniform practice in making such measurements is, therefore, desirable in order to reduce such uncertainty of measurement to a minimum. The so-called “three – wire method” of measuring thread pitch diameter, as herein outlined, has been found to be the most generally satisfactory method when properly carried out, and is recommended for universal use in the direct measurement of thread plug and thread setting plug gages.

Calibrating Thread Measuring Wires

The three wire method is the most accurate and universally recognized method of measuring the effective or pitch diameter of an external screw thread or thread plug gage. The pitch diameter is the most important measurement which can be made on a thread because it reflects the widest spectrum of potential defects in a thread gage or threaded part.

Thread Measuring Wire Calibration

Thread measuring wires are calibrated on a functional basis so as to compensate for deformation when the wires are being used.

Thread Measuring Wires - The Foundation of Proper Thread Calibration

When you are calibrating thread plugs, thread setting plugs and AGD style thread ring gages it is important to know the correct size and proper constant of the thread measuring wires, as they provide the foundation for accurate thread gage calibration. Working thread plugs and thread master setting plug gages are calibrated by means of the three-wire method. The degree of accuracy in the results of your readings depends on the accuracy of the thread measuring wires. An error of one unit in the mean diameter of thread measuring wires will have a multiplying effect of three units in the pitch diameter of 60° thread plug gages.

Thread Measuring Wire Formulas

Wires which touch the thread at the pitch diameter are known as “Best Size” Wires. Such wires are used because the measurements of pitch diameter are least affected by errors that may be present in the angle of the thread. The diameter of the measuring wires is represented by the letter G.

Approximate Formulas for Measured Pitch Diameter

The following approximate formulas for computing the pitch diameter, from the measurement over wires, should be used only for screws having lead angles from 0° to 5°. These formulas neglect the effect of lead angle and give results which show the screw to be larger than the true condition. The formulas are for any wire size which will fit in the thread.

NPT Gages and NPTF Gages

NPT gages and NPTF gages document provides a complete overview of general purpose and dryseal pipe threads. This document describes the differences between class 1 and class 2 NPTF threads. L1, L2, L3, and 6 step gages are described in detail. Learn more about npt gages, npt pipe gages and npt pipe thread.

NPTF Class 2 Specifications

NPTF gages are manufactured per ANSI/ASME B1.20.5. Standard practice for gaging NPTF threads calls for using 2 or 3 gages in coordination with each other. The standard calls out class 1 and class 2 NPTF threads. Class 1 signifies that specific inspection.

Taper Pipe Thread Gages

Thread Check, Inc. offers a complete line of tapered pipe gages including special and custom designs. NPT general purpose pipe thread plug and ring gages are manufactured per ANSI/ASME B1.20.1. Threads are within the permissible limits of the tolerance. Feel free to contact Thread Check with any questions you have about taper pipe thread gages.

Taper Pipe Thread Gages, Part 2

The L2 ring is used to gage the effective external threads beyond the L1 location length. It is relieved by counterboring at the small end to a depth equal to L1 minus 1P. The L2 is used like the thin L1 gage is used with a count of the number of turns by which the product over travels or fails to reach basic.

Gages Required To Check Other Pipe Threads

Thread Check Inc. offers a complete range of standard and custom pipe thread gages. Review the chart for gages required to check other pipe threads.

Internal Thread Comparator Instructions

Clean mounting surface on frame and segments. Locating surfaces must be free of any lint or dirt to avoid incorrect seating of segments. Attach segments to frame with mounting screws. Segments are interchangeable top to bottom. Depress operating lever to be sure bottoms of segments match face to face (not cocked).

Selecting Gaging Rolls

Thread Check Inc. offers various types of interchangeable gaging rolls to check maximum and minimum limits of size, pitch diameter, and single element gaging.

The Tri-Roll Comparator System

The tri-roll comparator system provides a fast and efficient means of definitive thread inspection. Also, variable data output makes this gage a perfect statistical process control device. Routinely, the tri-roll thread comparator is used to analyze and distinguish the following characteristics: Functional diameter size, Pitch diameter size, Lead and/or flank angle deviation, Taper, and 120-degree out-of-round (lobing).

How to determine the proper gagemaker tolerance for a GO/NO GO cylindrical gaging application

The industry standard is referred to as the Ten Percent Rule. This common rule of practice requires that 10% of the product tolerance is divided between the GO and NO GO gauges. For plug gages a plus tolerance is applied to the GO member and a minus tolerance is applied to the No Go member. Ring Gauges receive the reverse tolerance direction so that the GO member is minus and the NO GO member is plus.

Dimensional Inspection of Parts Using Fixed Limit Gages

Choosing the proper inspection instrument is a critical quality control decision; the wrong device or method could produce inaccurate results, and also affect the cost and performance of the parts that are inspected. The following will give you a better understanding of fixed limit gages.

Fixed Limit Gage Fact Sheet

The fixed limit gage document provides a gagemaker tolerance chart for selecting gage tolerances as well as tolerance direction for various gages. The fixed limit gage fact sheet also explains how to properly determine gage tolerance for measurement applications. This fact sheet has much to teach about The fixed limit gage. Learn more about fixed limit gages.

Gage Tolerance

Thread Check’s gage tolerances and gage maker chart are listed in one convenient document for easy reference. This document provides tolerances for class X and class W tolerances of pitch diameter, major diameter, minor diameter, and lead for thread gages.

Create Your Own Gage Set

Use this guide to design your own 6" long custom feeler gage set. You can choose any combination of carbon steel and stainless steel blades (combined thickness not to exceed .875 thick). Your custom feeler gage set will be manufactured, assembled, and shipped within two weeks. A unique part number is assigned to every gage set combination for easy re-ordering.

Paddle Flat

Flatted or diamond shaped No Go plug gages are used to detect an ovality condition in hole diameters. It is suggested that the width be 1/3 of the gaging diameter. See diagram below. If geometry is critical it is recommended that the holed be inspected using single element gaging. Flatted or diamond no go members will not detect odd numbered lobed conditions.

API Thread Gages

Thread Check, Inc. offers API thread gages to Spec. Q1, Spec. 5B, Spec. 7, Spec. 11B as well as many special API gages. Our engineers have served on various API thread gaging subcommittees. API thread gages come in all types include casing-round, line pipe, tubing-non. Learn more about API thread gages.

Getting Ready For API Spec 5B1 with Gagemaker

In the next revision release of Spec 5B1 by API, the industry will be able to meet the requirements by using the Gagemaker MRP Gage System. MRP is the abbreviation for Manual Plug and Ring. When the API 5B1 specification is released ( 2012 ) it will allow a threaded connector to be measured and accepted exclusively with the use of the MRP and the rest of the thread element gages. The MRP series of gages accurately measure internal and external diameters of tapered threaded connectors. The MRP uses two accurately located pivoting shoes that rest on the crests of the threads. The MRP gages are easily preset to size using gage blocks, Mic Tracs, or other types of readily available measuring equipment.

API 5B 5.5.2 Thread Addendum

API 5B 5.5.2 thread inspection changes for thread addendum and crest diameter setting standards.


Per API 5B 5.6.2, thread form and angles "shall be assessed with an Optical Comparator/Profile Projector


Gagemaker's MRP® Gauging System Required!

ISO 594/1-1986(E) (obsolete – replaced by ISO 80369-7)

ISO 594/1 specifies the general requirements of conical fittings with a 6% (Luer) taper for syringes, needles and certain other medical equipment. ISO 594/2 covers the lock fittings for above. The first edition of ISO 80369-7 cancels and replaces ISO 594-1:1986 and ISO 594-2:1998, clauses, sub clauses, tables, figures, and annexes of which have been consolidated and technically revised.

ISO 80369-7 replaces ISO 594-2:1998(E)

ISO 80369 was developed to prevent misconnection between SMALL-BORE CONNECTORS used in a range of applications. ISO 80369-1 details the requirements to verify the designs and dimensions of SMALL-BORE CONNECTORS to ensure they do not misconnect with other SMALL-BORE CONNECTORS and that they secure safely and securely with the mating half.

ISO 594-2:1998(E) (obsolete – replaced by ISO 80369-7)

ISO 594-2 covers conical lock fittings with 6% (Luer) taper for syringes, needles and certain other medical equipment. The standard covers rigid and semi rigid materials and details the test methods.


Thread Check Inc. supplies a complete range of cylindrical tapered plug gages and cylindrical tapered ring gages for National Machine Tapers, Jarno Tapers, Brown and Sharpe Tapers, and Morse Tapers. All standard tapers are manufactured per ASME/ANSI B5.10-1994 (R2008) Class Z unless otherwise specified. Thread Check Inc. also designs and builds custom tapered plug gages, custom tapered ring gages, and Taper pipe thread gages for a wide range of industries and applications. Other types of tapers include medical luer tapers, Cat V Flange Tapers and Steep Machine Tapers. Thread Check has a custom order form which makes ordering cylindrical tapered gages straightforward.

Custom Gauges

Custom thread gauges can be engineered and built to qualify your special thread designs. Building thread gauges with special thread dimensions including modified leads, angles, pitch diameters and special lengths is our specialty. Thread Check Inc. offers custom thread ring gages, custom thread plug gages, special concentricity gauges, custom flex plug gauges, and lead lock gauges.

3 Types of Gage Certification

Is a general statement that the gages have been manufactured and are in conformance to the applicable gage specification. The Certificate of Compliance states that the gages have been manufactured and inspected by highly trained personnel and found to comply with the dimensions and tolerances specified. The Certificate of Compliance states that the primary reference standards for the gage calibration are traceable to System International (S.I.) units through the N.I.S. T - National Institute of Standards and Technology. The N.I.S.T. number referenced on this cert is being phased out by the requirements of A2LA. The Certificate of Compliance also states that the gages are inspected in compliance with MIL-STD 45662A, ISO 10012-1, and ANSI/NCSL Z540-1.

White Paper on Resolving Measurment Disputes

Disputes over measurements can be costly for both parties to resolve and may hinder ongoing relations between suppliers and users of gages and instruments. Often it is simpler for both parties to agree to accept an average value of their readings as the final ‘size’ or the point at which their readings plus measurement uncertainties overlap.

Why Measurement Uncertainty is Better Than a Simple "Reading"

Measurement Uncertainty – This term refers to a measurement plus or minus a particular range that best represents the true value. This allows for the fact that a true, actual reading may not be entirely accurate, and so the range accounts for that possibility.

Change In Calibration Certificate Format – Removal Of NIST Number

Many customers will soon see a change in how the gauging and metrology industry references the N.I.S.T. number on calibration certificates. NIST is the acronym for National Institute of Standards and Technology.

About Engineering Metrology Toolbox

The NIST goal is to provide world-class engineering metrology resources to the U.S. manufacturers. This web site is one of an array of mechanisms they make available to our customers to help them achieve high-accuracy dimensional measurements traceable to national and international standards. Their goal is to assist you with improving your measurement capabilities.

Rotary Thread Inspection Tool Specifications

This document provides taperlock sizes AGD-American Gage Design Taperlock thread plug gages that are compatible with the Rotary Thread Inspection Gage. The document also specifies the standard maximum depth limits for the gages. Table 22 of the ANSI/ASME B47.1-1998 is also attached to this document to show thread plug gaging member blank standards.

ASTM Hardness Conversion Chart
Approximate Hardness Conversion Numbers for Non-Austenitic Steels, According to ASTM E-140. The Conversion Values contained herein should be considered approximate only and may be inaccurate for specific applications
Roundness Correction Chart for Hardness Testing

When testing cylindrical specimens, the accuracy of the test will be seriously affected by alignment of elevating screw, Vee-anvil, indenters, surface finish, and the straightness of the cylinder. These corrections are approximate only and represent the averages, to the nearest 0.5. Rockwell and Rockwell superficial numbers, of numerous actual observations.

ASTM Hardness Minimum Thickness Requirements

Minimum allowable thickness for a corresponding hardness in the respective scales.

Rockwell Hardness Scale Indentor Load Chart

Rockwell Hardness Scales

Mahr uMaxum® II Digital Comparitor - Standard

Mahr uMaxum® II Digital Comparitor Inch/Metric - operator selectable with switchable resolution.

Dimensional Inspection of Parts Using Go and No Go Gages

Go and No Go Gages are typically simple devices like Go and No Go plug gages, Go and No Go ring gages or Go and No Go Snap Gages that contain no moving parts and are easy to use. As such, their use is very common. Go and No Go gages are also easily portable, do not suffer breakdowns in service, and typically do not require power.

Mahr Digimar Height Measuring and Scribing Instrument 814 SR

Hardened and lapped contact surface which produce both a smooth and even movement.

Mahr Digimar Height Measuring and Scribing Instrument 817 CLM

The new Height Measuring Instrument Digimar 817 CLM with the innovative Quick Mode. Highly accurate rapid measurements, a wide range of measuring and evaluation possiblities and excellent operator comfort.

Mahr Micromar Digital Micrometer - 40 EWR

With this new generation of reference micrometers, mahr once again sets a new standard in the micrometer product segment. the new reference system from mahr is extremely energy efficient, when the micrometer is in standby mode almost no power is required; thus doubling the life span of the battery compared to a conventional digital micrometer. Due to the new reference system from mahr the handling of the digital micrometer has become considerably simpler and more far comfortable, as the zero position is secured, thus avoiding operating error. The micromar micrometer 40 ewr with the protection class ip65, offering excellent resistance against dust, coolants and lubricants and is ideal to be used in the most difficult workshop conditions. furthermore, if you need to document your measured data, the marconnect interface offers you the optimal connection to your evaluation system.

Mahr Multimar 36B - I.D/O.D Gage
The economical way to check outside diameters on the shop floor.
Mahr Precimar Linear 100 Measuring System w/MarCheck

The Linear 100 is very flexible when it comes to external measurements, with a direct measuring range of up to 50 mm (2") and an application range of up to 100mm (4"). For internal measurements, the application range is 15 mm to 100 mm (0.59" to 4"), with the additional option of 6 mm to 100 mm (0.25" to 4").

Mahr Marcal Digital Caliper 16 ER

Mahr MarCal Digital Caliper 16ER provides immediate measurement due to the reference system.

Mitutoyo Screw Thread Micrometers Series 326, 126

Mitutoyo Screw Thread Micrometers Series 126 and 326 are offered with anvil-spindle tip sets for 60 degree and 55 degree screw threads. The optional V-Anvil and conical spindle are made of high grade special steel, hardened and precision ground.

Mitutoyo Series 158 Optical Flats

Mitutoyo Series 158 Optical Flats are used for inspecting the flatness of micrometer’s or gage block’s measuring faces with high accuracy.

Mitutoyo Paper Thickness Micrometers

Mitutoyo Series 169 Non Rotating Spindle Type is specifically designed for paper thickness measurements.

Reference Standards

A common issue of measurement problems is the use of standards and specifications that may be outdated. User of these standards should contact the reference sources to ensure they are working to the most current standard. The following list covers many popular gaging and measurement standards.

Mitutoyo Optical Parallel Series 157

Parallelism Check between Measuring Faces by Means of Interference Fringe Produced by an Optical Parallel. The parallelism between the measuring faces can be determined as follows; place the optical parallel to the anvil and observe the number of interference fringes produced on the spindle side under the measuring force of the micrometers. The parallelism is about 1µm (0.32µm x 3 = 0.96µm). Fringe on the anvil side must not be more than one.

Mitutoyo Telescoping Gage Set Series 155

Mitutoyo Telescoping Gages Series 155 feature spring-loaded plungers that expand within the bore (or groove), allowing determination of the internal diameter or groove width). With a knurled clamp. Supplied in a fitted pouch.

Mitutoyo Uni-Mike Interchangeable Anvil Type Micrometers Series 117, 317

Mitutoyo Uni-Mike Interchangeable Anvil Type Micrometers measure tubing thickness, shoulderedge distance, rivet head height, etc. with interchangeable anvils (flat anvil, rod anvil, V-anvil).

Mitutoyo Tube Micrometers Series 115, 295

Mitutoyo Series 115, 295 Tube Micrometers are designed to measure the wall thickness of various tubing. The tube micrometers have two combinations of measuring faces (carbide tipped): spherical-flat type, and spherical type.

Mitutoyo Standards for V-Anvil Micrometers Series 167

Mitutoyo V-Anvil Micrometer standards are specially designed for the zero point setting of screw thread micrometers. Supplied in fitted carton.

Mitutoyo Standards for Screw Thread Micrometers Series 167

Mitutoyo Screw Thread Micrometer standards are specially designed for the zero point setting of screw thread micrometers. Supplied in fitted carton.

Mitutoyo Outside Micrometers w/ Friction Thimble Series 103

Mitutoyo Outside Micrometers Series 103 feature Hammertone, baked-enamel-finished Frame with ratchet stop or friction thimble for exact repetitive readings.

Mitutoyo Ratchet Thimble Micrometer Series 101, 102

Mitutoyo Ratchet Thimble Micrometers feature a ratchet function that works both from the thimble and the speeder, allowing easy one-handed operation. The micrometer features a clearly audible ratchet operation for reassurance that measurement is being performed at constant, preset force. The micrometer is provided with a Certificate of Inspection and a standard bar except for 0 - 25mm and 0 - 1” models.

Mitutoyo Outside Micrometers Series 104

Mitutoyo Outside Micrometers Series 104 features a wide measuring range with interchangeable anvils and ratchet stop for constant force.

Mitutoyo Outside Micrometers Series 107

Mitutoyo Outside Micrometers Series 107 uses a dial indicator for direct GO/NG-GO judgment for mass-produced parts with anvil retracting trigger for quick measurement.

Mitutoyo Spindle Attachment Tips

Spindle attachment tips are available to measure odd work pieces.Several convenient anvil attachments are prepared by Mitutoyo. Among them the most often used one is the ball attachment. The ball attachments are hardened steel balls with .200” and.250” diameters which are placed on the .250” and .315” diameter anvils, respectively, by rubber caps. With these attachments, regular micrometers can measure cylindrical wall thickness, but, .200” or .250” must be subtracted from the readings. Other attachments shown here are .500” in length. The added amount must be subtracted from the reading.

Mitutoyo Series 516 Gage Blocks

Precision gage blocks are the primary standards vital to dimensional quality control in the manufacture of parts. Mitutoyo offers gage blocks in a choice of rectangular or square, metric or inch and steel or CERA (ceramic) types.

Selecting Gage Blocks

Select gage blocks in accordance with the combination range required. If a large length is required, add a long block set. Select gage blocks in accordance with the minimum length step required. Add wear block sets if necessary.

Functional Thread Inspection Gagemaker

Functional gauging takes into account the cumulative effects of diameter, lead, taper, flank angle and form error. Experience the same functionality of ring and plugs with the added benefit of accurately inspecting a range of sizes.

Measurement Uncertainties Policy

Effective January 1st, 2012, all ISO/IEC 17025:2005 calibration laboratories are required to begin reporting measurement uncertainties for each measurement result.  Fox Valley Metrology - Thread Check Inc. prides itself on being one of, if not the only lab to offer this via automated software.  This automation allows us to provide this service at no additional cost.

Mitutoyo ABSOLUTE Digimatic Micrometers Series 227

The Mitutoyo ABSOLUTE Digimatic Micrometer Series 227 with an adjustable measuring force offers a constant and low measuring force mechanism with a non rotating spindle.

Mitutoyo Blade Micrometers Series 422, 122

The Mitutoyo Blade Micrometer Series 422 and 122 non-rotating spindles are used for measuring the groove diameter of shafts, Keyways, and other hard to reach portions. The blade micrometer features a ratchet stop for constant force.

Mitutoyo Coolant Proof Micrometers Series 293

Mitutoyo Coolant Proof Micrometers Series 293 with dust and water protection conforming to IP65 level enables use in environments exposed to cutting oil and other fluids. Measurement data output function is available with a water resistant connection cable.

Mitutoyo Disk Micrometer Series 369, 227, and 169

Mitutoyo Disk Micrometer Series 369, 227, and 169 are designed to easily measure root tangent length of spur gears and helical gears. The disk micrometers feature a non-rotating spindle to eliminate torque on the work piece.

Mitutoyo Caliper Type Micrometers Series 343, 143

Mitutoyo Caliper Type Micrometers function like calipers with greater precision. The ratchet stop provides constant force.

Mitutoyo Crimp Height Micrometers Series 342, 142, 112

Mitutoyo Crimp Height Micrometers are specifically designed to measure the height of crimp contacts.

Mitutoyo Gear Tooth Micrometers Series 324, 124

Mitutoyo Gear Tooth Micrometers Series 124, 324 measure over pin diameter of gears with precision steel and carbide ball tipped measuring faces. Interchangeable ball anvil – spindle tips for various gear modules are optional.

Set To Number For Barcor Chamfer Gages

Barcor does not keep a record of the Set To numbers because they can and do change over time as the tip (only true of the 1" or smaller gages) wears with heavy use.

The following instructions is how to determine a Set To number for a chamfer gage:

Thread Lead Inspection - Gagemaker

The lead or pitch of a thread is one of the most important elements on a thread and directly
affects a part’s functional size.
Lead error is most commonly generated by incorrect programming or manual and CNC lathes not
cutting properly.It’s important to take lead measurements throughout the thread length.These readings
help detect programming error, machine tool error and worn lead screws on your lathe.
Lead gages inspect both internal and external lead on a variety of thread forms.

Technical Information

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