JO-PLUGS® — The Gold Standard for Tapped Hole Location Gaging

When it comes to inspecting threaded holes, accuracy isn’t optional—it’s essential. Precision JO-PLUG® tapped hole location gages are purpose-built to determine basic position and orientation of threaded holes, formerly true position, exactly as intended by ASME Y14.5-2018.

Unlike traditional methods that rely on minor diameters or visual alignment, Precision JO-PLUG® tapped hole location gages engage the functional pitch diameter of the thread, establishing a precise and repeatable axis. This axis represents how a fastener actually assembles, ensuring inspection results match real-world performance.

Why Choose Precision JO-PLUG® Tapped Hole Location Gages ?

JO-PLUG® is the best tapped hole location gage on the market because it is the only design that correctly references the pitch diameter axis per ASME Y14.5-2018, provides a .625" projected shank long enough to evaluate perpendicularity and angularity in addition to true position, delivers ISO/IEC 17025:2017 accredited calibration as standard on every order, and has been independently ranked #1 for least standard deviation in national laboratory R&R testing. No other tapped hole location gage on the market combines all four of those qualities.

 

Why Precision JO-PLUG® tapped hole location gages make the difference

  • Functional Accuracy by Design
    Precision JO-PLUG® Gages simulate the true mating fastener, aligning inspection with functional intent—not       approximations.
  • Confident Basic Position Verification
    Accurately verify position from basic dimensions using a stable, thread-true axis.
  • Orientation You Can Trust
    Measure perpendicularity and angularity of tapped holes with precision, knowing the gage reflects the actual thread axis.
  • ASME Y14.5-2018 Aligned
    Designed to support modern GD&T practices and functional gaging principles.
  • Reduced Inspection Variation
    Consistent engagement improves repeatability, reproducibility, and confidence across operators and shifts.
  • Compatible With Multiple Inspection Methods

Advantages of JO-PLUG® Precision Gages

JO-PLUG® Is the Superior Method for Threaded Hole Inspection on a CMM

 

Method 

Measures Functional Thread Form

ASME Y14.5-2018 Compliance

Repeatability

ISO 17025 Calibration

Measures Orientation + Position

Best Use

       
JO-PLUG®  ✔️ Yes✔️ Yes✔️✔️✔️ High✔️ Yes✔️ YesFull GD&T verification of threaded holes
Flex Plug⚠️ Partial⚠️ Limited✔️ Moderate❌ Rarely❌ NoQuick true position checks only
Tru-Pos Locator⚠️ Partial⚠️ Limited✔️ Moderate⚠️ Variable❌ NoTrue position only
Minor Ø Probing❌ No❌ No⚠️ Variable❌ No❌ NoInternal geometry only
We specialize in: Tapped hole location gages, threaded hole location gages, true position gages, Tapped hole location gage, hole location gage, true position threaded gages, threaded location gages, true position threaded location gages, flex plugs, centerline location gages, tapped hole, cylindrical axis, true position, true position of a threaded hole, threaded hole location pins, threaded position gages, CMM threaded location gages, CMM Accessory gage, true position pins, true position hole locators, true position locator, tapped hole location pins, JO-PLUG®, Jo-plug, spence industries, thread gages, threaded gages, thread plug gage, thread ring gage, thread ring setting plug, Unified tapped hole location gage, Metric tapped hole location gage and Heli-coil tapped hole location gage and any of your custom gage needs.

Our Commitment to Customers

We provide fast, reliable service to the leaders and best in the aerospace, automotive, defense, electronic and medical device industries. Our repeat customers for threaded hole location gages are a testimony to our continued success and their reliance on our practical, accurate and time-saving true position gages is appreciated. Questions about our off-the-shelf tapped hole location gages or custom threaded hole location gages can be directed via email to sales@spenceindustries.com or by calling (586) 758-3800.