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TDWIN – Thread Disk Software for Straight Thread Dimensions

The Thread Disk™ engineering software (TDWin™ ) calculates critical dimensions for threads based on ANSI tables and formulas. Thread types supported by the program include: UN, UNJ and UNR Series, Acme, Stub Acme, Stub Acme Modified I and II, Metric M & MJ, 7° X 45° Buttress, and General Purpose Pipe Threads.

To generate critical dimensions instantly, enter basic thread information on the Thread Type Entry screen, such as: thread type, thread class, nominal diameter, and threads per inch. Once the results are computed, tabs at the bottom of the program allow selection of several types of calculated information, including dimensions and tolerances for product threads, ring gages, set plugs, plug gages or Gagemaker’s Thread Diameter gages.

TDWIN provides the important master setting values for setting Gagemaker PG-6000 Series, RG-7000 Series, PD-6000 Series, and PD-8000 Series gages to flat and V standards.

If measuring internal and external shallow taper diameters is a problem, the Ball mic SET DIM Tool provides setting dimensions for ball micrometers or Gagemaker’s BX-1000 groove gage. The program calculates ball mic settings for any tapered surface geometry.

The software also provides differential analysis tolerance.  This is the value received when comparing the pitch diameter tolerance and the functional diameter tolerance of a thread.  The spec says that if a threads pitch diameter and functional diameter measured tolerances are within 40% of the total pitch diameter tolerance, then you can be geometrically sure that the lead, form, and ovality values of the thread are to the correct specification without independently measuring each of these additional thread features. This is important when performing a System 22 inspection of a thread.

Other features of the program include the ability to print thread dimension reports, providing a paper copy of any calculation. These reports provide the same critical dimensions that display in the program. A multiple calculation window capability is a feature that allows performing several different thread calculation at the same time.

System Requirements

  • Windows XP or higher
  • 64 MB RAM
  • 3 MD of free hard disk space
  • USB drive


  • Uses ANSI tables, formulas, and tolerances
  • Calculates standard and non-standard product thread diameters from #000 to 99.8″
  • Calculates ANSI ring and plug gage dimensions
  • Addresses pitches from 1 to 400
  • Calculates Gagemaker style thread gage seting dimensions


JSS Tubing and Casing Inspection

Tubing & Casing JSS® Thread Inspection System

Thread Check Inc. offers Gagemaker’s JSS® Tubing & Casing Thread Inspection System which takes the guesswork out of inspecting tubing  and casing. The Gagemaker Tubing & Casing Thread Inspection system inspects all required thread elements – Insert Identification, Thread Form, Crest Diameter & Ovality, Thread Lead, Thread Height, and Thread Taper – all with the precise accuracy required in today’s demanding industry.

  • Optimize performance for tubing and casing.
  • Extend longevity of tubing and casing.
  • Scrutinize all thread elements with greater precision and accuracy.
  • Inspect all types of tubing and casing connectors including API round thread, long thread, short thread, line pipe, and buttress.
  • Protect against mechanical forces such as tension and leakage that tend to destroy tubing & casing connection.
  • Inspect both standard and non-standard connections – all using the same gages.
  • Ensure proper thread interference with pipe and coupling make-up.
  • Pinpoint thread errors that cause expansion of the coupling and compression of the pipe end



Insert Identifiers

The first step in the quality process is to ensure the threading insert being used is correct for the job.
Use the JSS™ Thread Insert Identifier Template to quickly verify that the correct threading insert has been selected as well as check the full topping profile of both internal and external inserts.



Inspection Setup

TDWIN Taper™ is the only software program dedicated to the manufacturing and inspection of downhole tubular connections. It has everything you need to machine, inspect, and document tubular connection threads. TDWIN Taper™ relies on API and industry standard tables and tolerances. TDWIN Taper™ displays connection drawings, inspection gage information, and setup and inspection reports. Simply, it is a must have for any machine shop.

Thread Form

Thread form accuracy is important if two connectors are to make-up properly. Using a JSS Thread Profile Gage and a JSS Thread Addendum Gage provide a quick check of the thread to ensure that the form is correct. Thread form verification ensures form accuracy. Also, checking thread form will ensure the first imperfect thread is fully deburred.
Thread form is defined as its profile in an axial plane for a length of one pitch. Most importantly, verifying thread form is a recommended inspection for API connections and ensures form accuracy.


Thread Lead Inspection

API Mandated Requirement

Thread Lead is one of the most important thread elements to monitor. Not only is lead inspection an industry wide practice for rotary shouldered connections, it is an API mandated requirement. Lead error is most commonly generated by manual and CNC lathes not cutting properly.

Verifying thread lead is within tolerance is a required inspection according to API specification. Application of a Gagemaker Lead Gage to a setting standard and then to the product confirms that the lathe is cutting properly. Lead variation has a direct effect on pitch diameter and how two connectors go together when made up.

Thread lead is the distance between threads, measured on a plane parallel to the centerline of the threaded part. Lead error has a direct effect on functional diameter, stand-off, and thread flank engagement.

Gagemaker’s lead gages inspect pin and box connections for multiple pitches and thread forms. The gages provide dimensional verification of product print data on the thread’s true integrity.

  • Interchangeable contact points allow inspection on a variety of thread forms and sizes.
  • Inspect RSC threads as well as Tubing and Casing threads
  • Requires presetting using Gagemaker’s lead gage setting standards.



Crest Diameter & Ovality Inspection

  • Thirty years ago, Gagemaker introduced the MRP® crest diameter and ovality gage which forever changed the industry. Today, the MRP® series of gages is the industry standard worldwide. Whether you call it Crest Diameter, Root Diameter, or Ball PD, Pitch Diameter governs the strength of the actual thread assembly and ensures API dimensional measurement specs are met. (Check out the new carbon fiber MRP AIR.)
  • The Gagemaker MRP® crest diameter gages measure the internal and external pitch diameters of tapered threaded connections. Any slight variations in diameter or ovality are immediately detected with these precision gages allowing the operator total control over the quality in the threads they are producing. MRP® crest diameter gages are extremely versatile with 3 models that can easily adjust to measure thread diameters ranging from 1½” – 20”. The ability to inspect and measure a range of internal and external diameters with one gage, eliminates the need for heavy, cumbersome, and expensive fixed limit ring or plug gages.

Thread Taper Inspection

API Spec. 5B Mandated Inspection

Tapered threads are a signature feature of API Tubing & Casing connections. Measuring thread taper is not only an industry wide practice, it is an API Specification 5B mandated inspection. During the manufacturing process, taper must be accurately measured and quantified to stay within the required specification limits. When subjected to a service load, taper error on threaded tubing and casing connections can lead to galling, improper fit, and reduced performance.

For the most accurate taper inspection, use Gagemaker taper gages to verify both the threaded pin and coupling meet all customer and industry requirements. Gagemaker’s taper gages are the best choice for measuring and controlling both pin and box taper values.



Thread Height Inspection

API Required Inspection

The correct thread height maximizes the performance of any threaded connection and is a required inspection by the API. Thread height affects both the interchangeability and integrity of a thread assembly. Thread height is the distance between the crest and the root, normal to the axis of the thread.

Gagemaker Thread Height Gages provide immediate feedback on how the thread height compares to the specification requirements. A shallow thread height may allow the connection to pull apart under critical loads.

Inspecting thread height can also help to detect a chipped tool. Gagemaker Thread Height Gages inspect both internal and external thread height for a variety of thread forms and provide immediate feedback on the integrity of your threads.














API 7-2 Second Addition

Companies working to the latest API 7-2 standard had until JUne 6 2017 to comply with the latest specification. Gagemaker, a leading developer and manufacture of precision mechanical inspection equipment for the Oilfield, Mining, Water Well, and General Machining industries has highlighted some key points below.

Requirements of indicator resolution have been updated for all lead, height, and taper gages. (API 7.4.1, 7.5.2, 7.6*) Now gages with
alternate indicators may not meet the new API requirements and must be replaced. Gagemaker recommends that you check your gages ASAP. Gagemaker has compiled a complete list of indicators and their compliant replacements at

  • New Bevel Diameters
  • Tables for connection bevel diameters have changed. (5.2.2)
  • Drawings Require New Angles All RSC box drawings now require a 30°max back-of-the-box angle. (6.3.3 Fig 10)

New Emphasis on the Effects of Lead Error.
The effects of lead error on standoff and pitch diameter can no longer be ignored. Greater emphasis has been placed on mandatory lead inspection. (7.2.1)

Gap on Hand-tight Parts Allowed If all of your element inspections are within tolerance, a gap between shoulders is allowed when parts are made-up hand-tight. (7.2.3 Fig. 14)

* API (American Petroleum Institute) maintains 685 standards and recommended practices. Many have been incorporated into state and federal regulations; as well as adopted by the International Organization for Standardization.

Thread Check Inc. is an authorized distributor for all Gagemaker products.

For more information on Gagemaker instruments please visit

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Thread Check Inc., Achieves New ISO 9001:2015 Certification

Thread Check Inc. is pleased to announce today that it has earned certification for the new ISO 9001:2015 standard. The comprehensive system audits covered every aspect of operations.

Thread Check is an industry leader in gaging and measuring instruments.

Any company that has been through the certification process knows that achieving ISO 9001 certification is demanding. Each individual in our operations must be wholly dedicated to the pursuit of quality. By scrutinizing our enterprise at every level, we assure that our customers are receiving superior customer service and the highest quality products.

ISO 9001 is a quality management system standard that was developed by the International Organization for Standardization. ISO is an association of governmental and nongovernmental organizations from many countries. The ISO 9001 standard is utilized to certify quality management systems that focus on continuous improvement, customer satisfaction and the active involvement of both management and employees in a process based approach.

Fulfilling the strict requirements of the ISO 9001 standard highlights our focus and commitment to deliver total customer satisfaction.

To achieve this certification, we demonstrated the management and operational practices to ensure that what we deliver to you adheres to the standards you expect. Our quality management system emphasizes service and support because your satisfaction is important to our business.

To us, ISO 9001 certification is much more than just checking a box. Certification represents our commitment to continuously improving our performance for our customers.

Thread Check Inc.'s customer service team is led by expertly trained sales engineers and supported by some of the industry's most talented manufacturing engineers and gauging experts.

ISO 9001 Certificate

Thread Check Inc.



Thread Check Inc. Introduces Technical Video Series

Video on How to Use Thread Plug Gages

Thread Check Inc. has introduced a technical video series on gaging and measuring instruments. The first 3 videos with cover the basics of how to use thread plug gages, ring gages, and Thread Check's digital thread depth gage. The videos will help in answering the common question the company has received over 30 years. Thread Check plans to release more educational videos in the near future. The videos will assist Thread Check's customers' with gaging and measuring applications. All videos will be available on Thread Check's web site as well as posted to Thread Check's You Tube account. The videos are being produced by Ofer Cohen of Rabbit Foot Productions. Ofer Cohen is an accomplished videographer and independent filmmaker with over 30 years of extensive and diversified experience in global events, travel, adventure, and industrial work.

The first video on How To Use Thread Plug Gages explains the basic thread nomenclature specified on gages and handles and discusses the importance of calibration, handling and storage of the gages. The video provides clear detail on the basics of gauging a part with both the go and the no go gage members.


How to Use Thread Plug Gage Video



Flex Hole Location Gages

Thread Check Flex Hole Location gages

Flex Hole Location Gages by Thread Check Inc.

Flexible hole location plug gages also referred to as centerline hole location plugs are used to determine the true centerline to centerline distances of threaded holes. The flexible hole location gage is slotted at 90° increments to ensure positive location on the thread flanks regardless of hole size. This feature provides a firm locating grip without pulling the shoulder of the plug up against the hole face thus avoiding any squareness error being transferred to the centerline measurement. The center is concentric to the threaded section within .0002” TIR for probe location of coordinate measuring machines as well as plate inspection setups as “overpin” measurements. The flexible hole location gage can also be used with vee blocks to check concentricity to other diameters. Thread Check stocks flexible hole location gages in unified and metric sizes.


  • Positive grip on flanks regardless of hole size.
  • Center is concentric with threaded section within .0002” T.I.R. for probe location of coordinate measuring machines.
  • The .2500 +/- .0001(6.35mm +/- .0025mm) shank is concentric to the threaded section within .0002 T.I.R. prior to slotting and may be used with micrometers or plate inspection setups as “overpin” measurement.
  • Used with vee-block, concentricity checks can be made with other diameters.
  • Sizes #10 (M5 Metric) and smaller are solid tapered thread form from low limit to high
    limit of class 2B pitch diameters.

Gage sets are available. Thread Check’s expert sales engineers can assist you with selecting the correct gages for your application.
Tel:631 231 1515



Thread Check ISO Certification Audit

We are pleased to announce that Thread Check Inc. passed its 2016 ISO 9001:2008 Audit with a perfect score.

ABS Quality Evaluations conducted a full 1 day audit of Thread Check' quality management system. There were no major or minor non conformities found during the audit. This is the 7th year in row with zero nonconformities. This is a testament to our organization's continued commitment to customer satisfaction, employee empowerment and continuous improvement.

I would like to thank and congratulate all of our employees for their commitment to the quality management system.

Thread Check Inc. is now planning on implementing ISO 9001: 2015 for the coming year.


New Thread Check Catalog

Thread Check Inc., is proud to announce the release of our 2016 Precision Gage Solutions catalog with over 180 pages of precision gages, measuring instruments and technical information. Our new catalog is available for download or in an electronic book format for easy use. The new catalog has links to where our customers can shop on line, request quotes and view hundreds of technical articles. Use the table of contents to quickly turn to the product selection of your choice. Use electronic book marks for the pages you visit frequently. The new electronic catalog works across all platforms including tables and smart phones.

Thread Check Catalog 2016 Cover




Root Relief in Thread Ring Gages

All Thread Check Inc. thread ring gages are root relieved for longer gage life and more accurate gaging. Thread ring gages are manufactured with a root clearance in the major diameter which eliminates the possibility of interference from the full form section of the thread setting plug and major diameter of the part being gaged. This critical feature assures that the thread flanks are making proper contact.

Root Relief in Thread Ring Gages


Alternate Size Thread Measuring Wires

It is possible to use standard 60 degree thread measuring wires to calibrate 55 degree British thread plug gages and external product. Thread Check often receives inquiries for special thread measuring wires to calibrate Whitworth/British 55 degree threads. Although Thread Check Inc. can certainly supply these special thread measuring wires, the cost is higher and the lead time to manufacture is typically 4 weeks or more. The best solution is to select a standard 60 degree thread measuring wire which is close to the 55 degree thread measuring wire diameter and simply adjust the constant value. This alternative set of thread measuring wires with an adjusted constant for the 55 degree thread angle will achieve the same exact results. The same method can be applied to 29 degree Acme and 45/7 degree buttress threads.

All “Best Size” thread measuring wires have a maximum and minimum wire diameter that may be used to measure pitch diameter. Maximum and minimum thread measuring wires should be used which are safely within the limiting dimensions given by the formulas below.


Include Thread Angle Max. Best Min.
60° 1.010362p .57735p .505182p
55° .82573p .563692p .50568p
29° Acme .650013p .51645p .487263p

P=pitch  n=TPI   P=1/n

The wide range of standard wire diameters in stock found within the 60 degree inch and metric sizes and the 29 degree acme sizes makes it possible to find a wire diameter very close to a required British or special size. The measurement of pitch diameter is least effected by an error in the included angle of the thread by a wire diameter which is closest to the calculated best size wire.

Related topics regarding thread measuring wires:

Thread Check’s expert sales engineers can assist our customers with selecting the correct wire size and calculating the new constant value to ensure accurate measurements.

Thread Check Inc
900 Marconi Ave
Ronkonkoma, New York 11779
Tel: 800 767 7633