Accredited Slip Gauge (Gauge Block) Calibration Services
Slip gauges are the physical embodiment of the meter and the foundation of all dimensional measurement in your facility. At DRS Technologies, we provide expert slip gauge calibration services to ensure your reference standards maintain their integrity. Our laboratory utilizes high-precision gauge block comparators and laser interferometry to measure length, parallelism, and flatness to within millionths of an inch.
Why Gauge Block Integrity is Essential for Quality Assurance
Because slip gauges are used to calibrate other measuring tools (like micrometers and calipers), any error in the block is amplified throughout your entire production chain. Over time, slip gauges can lose their “wringability” due to microscopic scratches or develop dimensional changes due to material instability (growth or shrinkage). Regular calibration by DRS Technologies ensures your blocks meet the strict tolerance grades defined by ISO 3650.
Our Technical Slip Gauge Calibration Process
Our metrology specialists follow a rigorous clean-room protocol to ensure the highest level of measurement certainty:
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Cleaning and De-magnetization: Blocks are ultrasonically cleaned and de-magnetized to ensure no microscopic particles or magnetic pull interfere with the measurement contact.
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Visual Inspection and Deburring: We inspect for nicks, burrs, and corrosion. If necessary, we perform light “stone” deburring to restore the smooth, flat surface required for proper wringing.
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Wringability Test: We verify that the blocks can still “wring” (adhere to each other or a reference plate). Loss of wringability is a primary indicator that the surface flatness has degraded.
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Comparison Measurement: Using a high-stability comparator with dual inductive probes, we compare your blocks against a NIST-traceable “Master Set.” This process measures the deviation from nominal length at the center of the block.
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Parallelism and Flatness Audit: We verify that the measuring faces remain perfectly parallel to each other, preventing “point-contact” errors when the blocks are used in a stack.
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Certification and Traceability: Every set is returned with a comprehensive certificate featuring As-Found/As-Left data for every block, documented NIST traceability, and an expanded uncertainty statement.
Specialized Support for All Grades and Materials
DRS Technologies provides elite-level calibration for all types of gauge blocks:
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Materials: Steel, Ceramic (Zirconia), and Tungsten Carbide.
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Grades: Calibration for Grade 0 (Reference), Grade 1 (Inspection), and Grade 2 (Workshop).
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Shapes: Rectangular and Square (Hoke) style blocks.
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Metric and Imperial: Full support for sets ranging from 0.5mm to 1000mm or 0.010″ to 40″.
Frequently Asked Questions
What is the difference between Grade 0, 1, and 2 slip gauges?
Grades define the tolerance limit for length and parallelism. Grade 0 is the most accurate, typically used as a master reference in calibration labs. Grade 1 is used for inspecting parts and high-end tools, while Grade 2 is common for general workshop setup. DRS Technologies calibrates all grades to their respective international standards.
Why is temperature control so important for slip gauges?
Steel slip gauges expand or contract significantly with temperature changes ($11.5 \times 10^{-6} / ^\circ\text{C}$). To ensure accuracy, we soak all blocks in our climate-controlled lab for 24–48 hours at exactly $20^\circ\text{C}$ ($68^\circ\text{F}$) before measurement begins.
When should a slip gauge be replaced instead of calibrated?
If a block has deep scratches, significant corrosion, or has worn beyond its Grade tolerance limits, it must be replaced. During our calibration process, we identify “failed” blocks and can help you source individual replacements to complete your set.