Measurement Uncertainty: torque_wrench
GUM-compliant measurement uncertainty budget components and coverage factors for common engineering measurements. Covers Type A (statistical) and Type B (non-statistical) uncertainty sources with standard uncertainties, expanded uncertainties at k=2 (95%), and confidence levels for: length/dimension (caliper, micrometer, CMM, gauge block), mass (analytical balance, platform scale), temperature (Type K thermocouple, Pt100 RTD, IR pyrometer), pressure (Bourdon gauge, electronic transducer, liquid manometer), flow (orifice plate, turbine meter, Coriolis, ultrasonic transit-time), electrical (DMM, power analyzer), force (load cell), and torque (torque wrench). Also includes coverage factor reference rows (k=1/2/3, 68/95/99.7%) and distribution divisors (rectangular, triangular, normal, U-shaped). Per ISO/IEC Guide 98-3:2008 (GUM), NIST TN 1297, ISO/IEC 17025:2017.
| measurement type | uncertainty source | confidence level pct (%) | coverage factor k | distribution | divisor | expanded uncertainty k2 | expanded uncertainty unit | notes | standard uncertainty unit | standard uncertainty value | uncertainty type |
|---|---|---|---|---|---|---|---|---|---|---|---|
| torque_wrench | calibration | 95 | 2 | normal | 2 | 2 | pct_rdg | Torque wrench calibration per ISO 6789-2:2017; Class II click type: accuracy +/-4%; precision torque tester calibration U95 = 1-2% | pct_rdg | 1 | Type_B |
| torque_wrench | combined_standard_uncertainty | 95 | 2 | normal | 1 | 3.8 | pct_rdg | RSS: sqrt(1.0^2+1.5^2+0.5^2) = 1.87% reading; U95 = 3.7% of reading; torque wrenches are relatively imprecise instruments | pct_rdg | 1.9 | Combined |
| torque_wrench | repeatability | 95 | 2 | normal | 1 | 1 | pct_rdg | Type A: sd from 5 repeat applications at same setting; ISO 6789-2 requires 5 measurements; sd typically 0.5-1.0% | pct_rdg | 0.5 | Type_A |
This is a sample. Search the full measurement uncertainty dataset and 300+ more by creating a free account and accessing the database.
Get started for FREE