CDI 1501MRMH – 1/4" Drive Micrometer Torque Wrench
The CDI 1501MRMH is a 1/4-inch drive, dual-scale micrometer click-type torque wrench built for the small-fastener torque work at the core of daily aviation maintenance. Its 20–150 in-lb (2.3–16.9 Nm) range covers avionics mounting hardware, instrument panel fasteners, fuel system fittings, cabin interior attachments, and the AN/NAS hardware that holds light aircraft together. The compact 1/4-inch drive and 10.15-inch overall length reach spaces where a 3/8-inch wrench simply won't fit.
The documentation behind it matters as much as the wrench
Every 1501MRMH ships with its own serial number and a matching certificate of calibration traceable to the National Institute of Standards and Technology (NIST). That traceability satisfies tool control requirements in FAA-accepted maintenance programs, Part 145 repair station Quality Control Manuals, and ISO 9001 quality management systems — environments where an undocumented torque tool is a finding, not just an inconvenience. Meets or exceeds ASME B107.14 and ISO 6789. Accuracy: ±4% CW, ±6% CCW of indicated value from 20–100% of full scale.
Built for the shop, not the tool aisle
- Knurled metal handle withstands daily professional use — not the lightweight composite grip found on consumer alternatives
- Spring-loaded pull-down lock ring positively locks torque settings against drift mid-sequence
- Laser-marked dual scale reads in-lb and Nm simultaneously — no conversion chart needed
- Fixed ratcheting head with quick-release button for fast socket changes in tight panel access
- Audible click plus tactile impulse confirms torque in noisy hangar environments
- Rated to a minimum of 5,000 operating cycles for long service life
- Made in the USA by CDI Torque Products, a Snap-on Industrial Brands company
Where A&P mechanics use the 20–150 in-lb range
- Avionics tray mounting hardware and connector backshell fasteners
- Instrument panel hardware — alternators, voltage regulators, sensor brackets
- Fuel system fitting torque — AN fittings, banjo bolts, fuel cap hardware
- Cabin interior structural attachments and seat track hardware
- Small AN/NAS fasteners throughout airframe and firewall
- Light-duty GSE and tooling hardware in the same torque range
Why source aviation tooling from Pilot John International
Pilot John International is an aviation-specialist distributor — not a general industrial catalog. We serve Part 145 repair stations, FBOs, MRO operations, and flight schools across the U.S. Unlike mega-retailers who list this wrench alongside garden tools, we understand the documentation chain behind every tool we sell. Our on-site ISO 17025-accredited calibration laboratory means that when the 1501MRMH comes due for recertification, you send it back to the same aviation-specialist source —
| General Information | |
|---|---|
| Part # | 1501MRMH |
| Manufacturer | CDI |
| Specifications | |
|---|---|
| Accuracy (CCW) | |
| Accuracy (CW) | |
| Calibration Certificate | Individually serialized, NIST-traceable |
| Country of Origin | USA |
| Cycle Rating | 5,000 cycles minimum |
| Drive Size | 1/4" |
| Graduation | 1 in-lb |
| Handle | Knurled metal, dual scale, laser marked |
| Head Type | Fixed ratcheting, quick-release button |
| Indicator | Audible click + tactile impulse |
| Lock Mechanism | Spring-loaded pull-down lock ring |
| Overall Length | 10.15 in |
| Standards | ASME B107.14, ISO 6789 |
| Torque Range | 20 |
| Warranty | 1-year manufacturer |
| Weight | 0.90 lb |
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AIRCRAFT COMPATIBILITY
This item is for use on all aircraft.
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QUESTIONS & ANSWERS
Yes. The 1501MRMH ships with an individually serialized, NIST-traceable certificate of calibration and meets ASME B107.14 and ISO 6789 — the documentation and compliance specifications typically required in Part 145 repair station Quality Control Manuals. Always verify against your facility's specific RSM requirements.
The 1501MRMH covers 20–150 in-lb (2.3–16.9 Nm) in 1 in-lb increments. Accuracy is rated at ±4% clockwise and ±6% counter-clockwise of indicated value from 20% to 100% of full scale — consistent with the tolerances cited in aircraft maintenance manuals for structural fasteners.
A 1/4-inch drive wrench like the 1501MRMH provides access to small fasteners in confined panel spaces — avionics trays, instrument clusters, connector backshells — where a larger 3/8-inch drive head physically won't fit. The smaller head also gives finer control on low-torque hardware where over-torque risk is higher.
Yes. Pilot John International operates an ISO 17025-accredited, NIST-traceable calibration laboratory. We can recalibrate the 1501MRMH and issue a new individually serialized certificate. Contact us directly for current pricing and turnaround time.
