Leitech U.S. : The Authority in Precision Thread Depth Gaging
Leitech: The Industry Standard for Thread Depth Gaging

Leitech U.S. : The Authority in Precision Thread Depth Gaging


In high-precision manufacturing, the difference between a pass and a fail often comes down to the reliability of your thread depth data.
Whether you are navigating the strict requirements of Aerospace, Automotive, or Medical production, subjective estimation isn't an option.
The Leitech COMBI system is engineered to replace 'eyeballing' with traceable numerical truth—streamlining your inspection process and future-proofing your quality lab.




Engineered for tight +/- tolerances in Aerospace and Medical manufacturing.
NIST-Traceable Accuracy: Engineered for high-resolution inspection where standard analog gages fall short.
Resolution to 0.1mm or .005": A dedicated solution for Medical and Aerospace components requiring strict +/- depth control.
The "First Full Thread" Standard: Calibrated to ensure your measurements meet ISO 1502 requirements every time.
Dual Measurement: Watch how the Hi-Res COMBI verifies size and measures functional depth in one motion.
This video demonstrates the Hi-Res COMBI system, the original high-resolution thread depth gage designed by Leitech. While traditional manual gages struggle with tight tolerances, the Hi-Res scale allows for definitive measurement of functional thread engagement in precision-machined parts.
The Industry 4.0 standard for high-resolution digital thread inspection and data integrity.
LCD Display: Eliminate parallax error with instant, crystal-clear digital depth readouts.
Industry 4.0 Ready: Integrated wireless data output for seamless SPC (Statistical Process Control) tracking.
Operator Independent: Standardized digital measurement that removes "human feel" from the quality lab.
Metric/Inch Conversion: Toggle between units instantly for global manufacturing standards.
Experience the Leitech Digi-COMBI, the industry’s premier digital thread depth gaging system. This video highlights the integration of precision metrology with digital data collection, showing how Tier 1 suppliers automate their quality documentation and ensure 100% data integrity.
Eliminate operator fatigue with motorized torque consistency and digital depth verification.
Motorized Precision: High-speed inspection with 100% consistent torque entry every time.
Eliminate Fatigue: Designed for high-volume production lines where manual gaging leads to repetitive stress and data errors.
Total Process Control: Combines the speed of power-driven gaging with a high-resolution digital depth display.
Universal Application: The professional alternative to modified power tools for Aerospace and Automotive quality labs.
Watch the Leitech DMG (Digital Motorized Gage) redefine power-driven thread gaging. Unlike standard motorized drivers, the DMG is a purpose-built metrology system that verifies size and measures depth simultaneously, providing the speed of automation with the precision of a Leitech instrument.
In high-precision manufacturing, a thread that is "close enough" is a failure. For the Quality Engineer, the challenge isn't just measuring a hole—it’s maintaining absolute Process Control. This guide explores the transition from traditional, multi-step gaging to the System Leitech—the original dual-measurement solution. By consolidating thread size verification and functional depth inspection into one NIST-traceable operation, engineers can eliminate operator subjectivity, satisfy the most rigorous ISO 1502 audits, and reclaim up to 45% of inspection time.
In the Aerospace, Defense, and Medical sectors, if a measurement isn't traceable, it didn't happen.
Every Leitech gage is precision-engineered to meet or exceed ISO 1502 and ASME B1.2 standards. Unlike generic tools, our patented telescoping scales are calibrated specifically to the first full thread ridge, ensuring that your depth readings are NIST-traceable and audit-ready from day one. This pillar ensures total compliance with the most rigorous industry specifications, eliminating the risk of non-conformance reports during critical quality audits.
The System Leitech removes the "guesswork" from the shop floor. By utilizing a spring-loaded, integrated scale that rests flush against the part face, the gage provides a fixed, repeatable numerical value every time. This eliminates the variables of "operator feel" and parallax error common with separate gages or calipers. By standardizing the measurement method, you achieve high Gage R&R (Repeatability and Reproducibility) scores across all shifts and operators.
Measuring a hole's physical depth is not the same as measuring its functional thread depth.
Our system is designed to verify that the thread is fully formed and capable of accepting a fastener to the required depth. We measure functional thread engagement—the usable thread available for the assembly—rather than just the drilled hole depth. This distinction is critical for the structural integrity of precision-machined parts, ensuring that fasteners never "bottom out" or fail due to insufficient thread engagement.
Inspection is often the bottleneck of a high-speed machining cell.
By consolidating size verification and depth measurement into one single operation, the Leitech System reduces the inspection cycle by 45%. This dramatic increase in speed allows Quality Engineers to implement higher sampling rates and tighter process control without sacrificing production throughput. Reclaiming this inspection time allows for immediate ROI by increasing machine uptime and reducing labor-intensive measurement steps.
High-quality metrology should be an investment, not a consumable expense.
The Leitech Renewable "Replaceable Insert" System is a breakthrough in tool life management. When the "GO" thread member eventually wears, it can be swapped out in seconds while maintaining the calibrated handle and scale. This "Renewable" design reduces long-term tool consumption costs by up to 60%, providing a sustainable and lower cost-per-checked-hole ratio that satisfies both the Engineering and Procurement departments.
Modern manufacturing is moving toward Sustainable Metrology. Instead of treating gages as disposables, the Leitech system uses Member Removal Sleeves and Calibration Masters. This allows you to renew your handles indefinitely by simply replacing the worn thread member—reducing waste and lowering your total cost of ownership.
Leitech COMBI Gages measure functional Size and direct numerical Depth data - at the same time. Dual measurements, one tool.
By replacing subjective "eyeballed" estimates, unreliable turn-counting and depth-steps with a telescoping sleeve to provide actual, traceable, numerical data for tapped, bored, and reamed holes, Leitech empowers Quality Managers and Engineers to ensure absolute part integrity and process compliance in a single operation.
Whether managed by Metrology Gage Lab Departments or utilized by CNC Machinists on the shop floor, Leitech COMBI Gages provide the Industry 4.0 data-driven certainty required by Manufacturing, Design, Process, Production and Tooling Engineers for modern, high-precision manufacturing.

Simultaneous Size and Depth Measurement: Threaded or Cylindrical Holes
As the GO thread member enters the feature, the internal telescoping measuring sleeve automatically rests against the part face, providing a direct numerical depth reading. This single-operation approach eliminates the need for separate depth micrometers or the unreliable practice of counting turns or eyeballing depth steps.


The Variable-Depth Advantage:
Whether inspecting threaded features or cylindrical bores, the Leitech COMBI ensures a perfect assembly fit every time. By verifying functional size and actual depth simultaneously in one fluid motion, you eliminate the need for separate depth micrometers and the unreliable "counting of turns."
Experience a leaner Gage Lab. Because one Leitech COMBI measures variable depths for its specific size, a single tool can replace an entire set of traditional fixed-step gages. This drastically reduces calibration overhead and ensures you always have the right tool for any part depth on the print.
Elevate your process with the Digi-COMBI and DMG-Motorized series. These Industry 4.0 solutions offer high-resolution LCD displays and wireless data transfer, allowing you to capture actual numerical values for real-time SPC logging and 100% digital traceability.


The Leitech Solution: One-Operation Efficiency



















Q: What is the most efficient way to measure functional thread depth?
A: The Leitech COMBI Gage performs a functional size check and delivers a direct numerical depth reading in a single operation, eliminating the need for separate depth micrometers or unreliable turn-counting methods.
Q: How do you inspect and verify the depth of a tapped blind hole or bottoming thread?
A: The Leitech COMBI utilizes a precision telescoping sleeve that automatically rests against the part face as the GO member enters the thread. This provides a repeatable, traceable measurement of functional thread engagement depth for the fastener, preventing assembly failure and bottoming-out.
Q: What is "functional thread depth" and why does it matter?
A: Functional thread depth is the actual usable thread available for fastener engagement, measured from the first full thread ridge. Unlike nominal depth (which only measures to the bottom of the hole), functional depth ensures assembly safety and prevents fastener bottoming-out failures.
Q: Can I use Leitech gages for cylindrical holes?
A: Yes. System Leitech provides the same "Size + Depth" efficiency for cylindrical features as it does for threads. Our Cylindrical COMBI Gages verify the functional diameter of reamed, bored, or drilled holes while simultaneously capturing a direct numerical depth reading.
Q: How does Leitech reduce gage inventory costs?
A: Unlike fixed-step gages that only check one depth, the COMBI's telescoping sleeve measures variable depths directly. One tool replaces an entire set of fixed gages for that thread size.
Q: How much faster is Leitech compared to traditional methods?
A: By combining size and depth verification into one operation, Leitech reduces inspection time by approximately 50% compared to using separate gages or counting turns.
Q: What tool is used to measure thread depth?
A: The most efficient and accurate tool for measuring functional thread depth is the Leitech COMBI Thread Depth Gage. Unlike traditional methods that require separate gages or unreliable "turn counting," the Leitech System performs a functional size check and delivers a direct numerical depth reading in a single operation. This "One Tool, Dual Measurement" approach is the global industry standard for precision manufacturing.
Q: How do you check the depth of a thread accurately?
A: To check thread depth accurately, you must measure the functional thread engagement rather than just the nominal hole depth. Using a Leitech COMBI gage, the internal telescoping sleeve automatically rests against the part face as the "GO" member enters the thread. This provides a repeatable, NIST-traceable measurement of the usable thread available for fastener engagement, eliminating "operator feel" and parallax error.
Q: What is the rule for thread depth in precision machining?
A: The fundamental rule for thread depth is ensuring enough functional engagement to meet the load requirements of the fastener without bottoming out. According to ISO 1502 and ASME B1.2 standards, this must be measured from the first full thread. Leitech gages are engineered specifically to this rule, with the measuring scale calibrated to the first full thread ridge (held to a strict 0.5 pitch tolerance) for absolute compliance.
Q: Is the Leitech COMBI system compliant with FED-STD-H28?
A: Yes. The Leitech system provides full conformance to FED-STD-H28, Section 6A. The crest of the first full thread on Leitech GO members is held to a strict 0.5 pitch tolerance (+0 / -0.06 pitch) from the front face.
Q: What is the difference between "functional depth" and "nominal depth"?
A: Functional depth measures the actual usable thread available for a fastener to engage, accounting for the thread lead-in. Nominal depth simply measures to the bottom of the hole. Leitech gages are calibrated to provide functional depth—the measurement that matters for assembly integrity.
Q: How do I eliminate "operator feel" variability in thread gaging?
A: The Digital Motorized Gauge (DMG-COMBI) uses a motorized handle to apply standardized, consistent torque for every measurement, completely removing operator variability from the inspection process.
Q: How much time can be saved using a Leitech COMBI gage?
A: On average, the System Leitech reduces inspection time by 45% to 50%. By consolidating size verification and depth measurement into one single step, shops reclaim significant machine capacity and reduce labor costs in high-volume production environments like Automotive and Aerospace.
Q: Can one Leitech gage replace multiple fixed-limit gages?
A: Yes. Because the Leitech COMBI features a variable telescoping scale, one single tool can measure any depth within its range for that specific thread size. This allows manufacturers to reduce their gage inventory by up to 72%, as they no longer need to stock multiple "step gages" for different part numbers.
Q: How do I calibrate a Leitech COMBI Gage?
A: Calibration is performed using the Leitech Calibration Master to establish a precise, pitch-based Calibration Length (X). By adjusting the telescoping measuring sleeve to this traceable constant, Quality Manufacturing Managers ensure 100% measurement accuracy. This repeatable process guarantees that your thread depth data remains compliant with ISO/IATF and FED-STD-H28 international standards.
Q: Can I integrate Leitech gages into an automated SPC system?
A: Yes. The Digi-COMBI and motorized DMG-COMBI are engineered for Industry 4.0 integration, featuring RS232 and wireless data output for real-time SPC (Statistical Process Control). By transmitting actual numerical depth values directly to your quality software, these gages eliminate manual data entry errors and provide the 100% traceability required in modern, high-precision manufacturing.
Q: Can one Leitech gage measure different thread depths of the same size?
A: Absolutely. This is the core of Leitech Inventory Efficiency. Unlike traditional fixed-step gages that only verify one pre-set dimension, a single Standard COMBI Gage utilizes a telescoping sleeve to provide a direct numerical reading of any depth within its range. This allows Gage Labs to replace an entire set of several gages with one universal tool, significantly reducing calibration costs.
Q: Can Leitech gages be used in automated robotic inspection cells?
A: Yes, the DMG-COMBI (Digital Motorized Gage) is specifically designed for robotic automation. It features variable speed settings and wireless data transmission, but its greatest advantage is standardized motorized torque. By eliminating "operator feel" and providing consistent measurement force, the DMG-COMBI ensures maximum GR&R (Gage Repeatability and Reproducibility) in 24/7 automated production environments.
Q: Are Leitech thread gages repairable or renewable?
A: Yes. Unlike standard gages that must be scrapped when the "GO" end wears down, the System Leitech features Replaceable Inserts. Using our specialized Removal Sleeves, a worn insert can be swapped out in seconds, essentially renewing the tool at a fraction of the cost of a full replacement. This "Renewable" design is what makes Leitech the most cost-effective long-term solution for Tier 1 suppliers.
Q: Does Leitech offer solutions for non-threaded holes? A: Absolutely. The Cylindrical COMBI Gage provides the same "Size + Depth" efficiency for reamed, bored, or drilled holes. It allows for the simultaneous verification of hole diameter and functional depth, ensuring total quality control for every precision-machined feature.
A threaded or cylindrical hole that does not break through the part. Accurate depth measurement is critical here to prevent fasteners from bottoming out before achieving full engagement.
The actual usable length of thread that can accept a fastener, measured from the first full thread ridge. Unlike nominal depth, this ensures sufficient engagement to meet load requirements.
Dual-purpose measurement for non-threaded features like reamed bores or precision-drilled holes. System Leitech provides the same one-operation efficiency for these features as it does for threads.ads.
The specific reference point for Leitech depth measurement. A telescoping sleeve rests on the part face to provide a direct reading of this dimension while the GO member simultaneously verifies pitch diameter size.
The precise distance from the front face of the thread member to the zero-point on the measuring sleeve. This value ensures the gage conforms to FED-STD-H28 and international standards.
Inconsistency in results caused by different individuals applying varying force. The DMG-COMBI eliminates this variable through motorized, standardized measurement force.
Unlike "Go/No-Go" gages that provide only a binary pass/fail result, Leitech delivers a direct numerical reading. This data allows for precise CNC tool-offset adjustments based on quality audit-ready data.
Specialized extraction tools used to quickly and safely remove worn inserts from the Leitech handle. This allows you to renew the tool indefinitely, minimizing physical waste.
The verification that a threaded feature will accept its mating part. A Leitech "GO" member verifies size while the integrated sleeve simultaneously measures depth in one fluid motion.
A core benefit where a single variable-depth COMBI gage replaces a set of numerous traditional fixed-step gages. This significantly reduces Gage Lab overhead and calibration costs.
The elimination of operator subjectivity—such as "counting turns"—in thread inspection. Leitech provides a repeatable, data-driven process that ensures every feature meets exact engineer specifications.
Leitech gages are engineered for a lifetime of service via a patented design where worn inserts are easily replaced while the precision handle remains.

Stop guess and start measuring! From the standard workhorse to motorized automation, there is a Leitech COMBI solution designed to bring 100% metrological certainty to your shop floor.
Contact us today for a quote or a live demo of the COMBI system.
Authorized Master Distributor and Technical Support for the USA, Canada, Mexico and Puerto Rico.
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