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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




API Tapered Thread Engineering Software

API Tapered Thread software

If you are looking for API dimensional specification in one convenient package, the Gagemaker TDWIN Taper Software program is your answer. Gagemaker's TDWIN Taper software program provides all the necessary API specifications that control connection quality.  TDWIN Taper produces dimensional drawings and inspection data for API downhole tubular connectors based on the latest industry standards. All the necessary details to machine, inspect and document tubular connection threads are available in one indispensable program.

TDWIN Taper Software includes information for both preferred and non-preferred Rotary Shouldered Connections, Tubing and Casing Connections, and any combination of Crossover. The program provides standard connection types and sizes. It displays detailed connection drawings, inspection gage information, and setup and inspection reports.

The software displays dimensional drawings suitable for manufacturing. Both Pin and Box drawings can be printed.  The drawings comply with ASME Y14.5 standards for industry compatibility. The TDWIN Taper Software allows the user to print gage setup and inspection reports with your company logo and work order information. All reports and jobs can be saved for future reference.

Includes Connection Data for:

Rotary Shouldered Connections 

  • API Numbered Connections
  • API Regular
  • Full Hole
  • Internal Flush
  • Open Hole
  • PAC
  • Slim Hole
  • Wide Open
  • Extra Hole
  • H-90
  • Slimline H-90
  • External Flush
  • ACME Regular
  • ACME Streamline
  • Double Streamline

Tubing and Casing Connections

  • NUE Tubing
  • EUE Tubing
  • Line Pipe
  • Short Thread Casing
  • Long Thread Casing
  • USS Improved Buttress Tubing
  • Special Clearance Couplings
  • SR13 Seal Ring Groove Couplings

System Requirements 

  • Windows XP or higher
  • 1 MB RAM or more (recommended)
  • Screen resolution of 1024 X 768 minimum
  • USB 2.0 port (The program runs entirely from a flash drive.)
  • Active Internet connection
  • .Net Framework 2.0 or later installed


  • Follows API Specification 7.2, Dec. 2008, for Rotary Shouldered Connections
  • Follows API Specification 5B, Oct. 2008, for Tubing and Casing Connections
  • Presents “preferred” connections as well as interchangeable and obsolete
  • connections
  • Organizes data compatible with API and industry knowledge offered by
  • resources such as Smith, Joy, and Hughes
  • Displays Gagemaker style thread gages and gage setting information
  • Configures and prints reference drawings for manufacturing including:
    • standard pin/box/coupling
    • pin/box blanking
    • pin/box relief groove
    • box modified bore-back relief
    • special clearance couplings
    • SR grooved couplings
  • Produces gage setup reports for tubing, casing, RSC, and crossover  combinations
  • Provides inspection reports for all connection configurations selected
  • Customizes reports with your company logo
  • Saves reports to job files and recalls them for future reference
  • Provides web links to locate and purchase necessary gages and standards

Compact custom Flash Drive – Single User


Per API Spec 7 – Obsolescence Rotary Shouldered Connections

Per API Spec 7 - Obsolescence Rotary Shouldered Connections

In 1964, at the API Committee on Drilling and Service Equipment, a new series of rotary shouldered connections was adopted in order to improve the service performance of drill collars and tool joints. 11 of the 13 NC sizes were approved as standard.

For the new style of connections, the size designation is a two digit number indicating the pitch diameter of the pin member at the gage point and the style is referred to as the number style or numbered connection – NC. These NC connections utilize a V thread form having a .065 inch flat crest and a .038 inch rounded root. This form is specified as the V-0.038R form. This V .038R form mates with the V-0.065 form that is employed on all API internal flush ( IF ) connections and on the API 4 inch full hole ( FH) connection.

All API IF and FH connections are now considered obsolescent and appear in the appendixes I,J, and K of API specification 7.

Of the new NC connections there are 5 sizes that have the same  pitch diameter, taper, pitch, and length of thread as the corresponding size in the IF style and one corresponds to the 4 FH connection.

These 6 connections in the number style can be gauged with the same gauging practice and same gauges required for the equivalent connections.

For information you may contact Thread Check Inc at  or call us at 631 231 1515

Per API Spec 7 - Obsolescence Rotary Shouldered Connections


Macaroni Tubing Threads

Thread Check Inc offers the full range of macaroni tubing thread gages

American MT, AMT, AMMT
Macaroni Tubing Threads
MT is Macaroni Tubing; AMT is American Macaroni Tubing; AMMT is American Mining Macaroni Tubing. The connections are three (3) names given to the same basic threaded connection.
Contact Thread Check Inc for more info -

Sucker Rod Pin and Box Connections

Thread Check Inc offers sucker rod thread gages  per API spec 11B

The designations are listed below

For sucker rod pin connections

Go pin thread ring gage = P8
No Go pin thread ring gage = P6

Pin cone ring gage is P4 which is used on polished rods only

Go pin P2 ring gage is used on polished rods and does not check 9 degree cone

For sucker rod box connections

The go box thread plug gage B2 does not check 9 degree cone on polished rod couplings and sub couplings.

Box cone plug gage B4 is used on polished rod couplings and sub couplings. Do not use on sucker rod couplings.

No go B6 is used on sucker rod couplings and sub couplings

The product pin should not enter the P6 ring gage more than 3 turns.

The product pin should enter the P8 ring gage to shoulder face pin contact

A .002" feeler gage should not enter between the face of the gage and the pin shoulder face.

For more information and pricing on sucker rod plug and ring gages contact Thread Check Inc

Sucker Rod Gages from Thread Check


800 767 7633


Gagemaker Ball Pitch Diameter Gages

Thread Check offers a wide range of pitch diameter gages manufactured by Gagemaker. These types of gages are commonly known as ball PD gages as they accurately measure pitch diameter which is one of the most important characteristics of a thread. Pitch diameter represent the widest spectrum of potential defects on a screw thread. Improperly sizes pitch diameters compromise the load capacity of your threaded components.

Gagemaker uses contact point (or contact ball) gages to inspect lead, taper, height, and pitch diameter on nearly any type of thread. Generally, these gages require two contact
points. Our points are inter-changeable; one set of points often can be used on different types of inspection gages. For best results, we still recommend one set of points for each gage.
Gagemaker offers spherical points and truncated points to measure pitch diameters. Truncated points as illustrated ensure contact on the flanks of the thread pitch line and eliminate the possibility of bottoming out on the root or minor diameter of the thread.

truncated points are used to measure pitch diameters of certain straight threads, primarily Acme, Stub Acme, and the modified Stub Acme threads.

Spherical points are commonly used for *UN Series, Metric, 7x45 Buttress, and nearly all tapered threads (tubing & casing and rotary shouldered connections).

Note: Remember when setting a gage with truncated points set on the truncated surface of the point. Gagemaker will provide set-to-flat value to compensate for the truncation.

Gagemaker Ball Pitch Diameter Gages

Gagemaker Ball Pitch Diameter GagesGagemaker Thread Gages


Accurately Inspecting Rotary Shouldered Connections without plug and ring gages

Gagemaker’s new Joint Strength System – JSS is fast, versatile and effective at certifying RSC connections. The JSS System allows the inspector to measure and have greater control over all the attributes that affect performance of the connection.

This gauging system will inspect any API thread and verify the accuracy to API specification tolerances.

Inspecting Rotary Shouldered ConnectionsInspecting Rotary Shouldered ConnectionsInspecting Rotary Shouldered Connections without plug and ring gagesInspecting Rotary Shouldered Connections without plug and ring 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.

Other thread element gages readily available from Gagemaker are thread lead gages, thread taper gages, thread height gages, and thread profile gages. These gages are readily available and extremely versatile for inspecting a large range of threaded connectors.


API Spec 5B1 with GagemakerAPI Spec 5B1 with GagemakerAPI Spec 5B1 with GagemakerThread Lead GagesThread Lead Gages