Lockwire / Safety Wire
MS20995 & NASM25173 Part Number Decoder
The complete reference for reading and cross-referencing safety wire part numbers. Decode any MS20995 or NASM25173 designation — alloy suffix, diameter code, and stocked part lookup — all in one place.
American Wire Works — Folcroft, PA — stocking safety wire since 1940
How to read an MS20995 part number
Every MS20995 part number follows the same three-segment pattern. Take MS20995C32 as an example:
MS20995 — Base Spec
The military standard designation for safety wire, also published as NASM25173 by the aerospace industry. Defines tensile strength, elongation, and coating requirements.
C — Alloy Suffix
One or two letters identifying the wire alloy. Controls temperature limit, corrosion resistance, and application suitability. See the alloy table below.
32 — Diameter Code
A two-digit number equal to the wire diameter in thousandths of an inch. 32 = 0.032", 20= 0.020", and so on.
NASM25173 alloy suffix codes
| Suffix | Alloy |
|---|---|
| C | Corrosion-resistant steel (302/304 CRES) |
| NC | Nickel-copper (Monel 400) |
| N | Nickel-chromium (Inconel) |
| CY | Cadmium-plated copper |
| AB | Blue anodized aluminum |
| CU | Bare copper |
Common MS20995 diameters
| Part Suffix | Diameter |
|---|---|
| .020 (20) | 0.020" |
| .025 (25) | 0.025" |
| .032 (32) | 0.032" |
| .041 (41) | 0.041" |
| .047 (47) | 0.047" |
MS20995 stocked part cross-reference
All part numbers below are stocked by American Wire Works. Click any part number to go to its product page.
| Part Number | Alloy | Diameter | Product Page |
|---|---|---|---|
| MS20995C20 | 304 SS | 0.020" | View → |
| MS20995C25 | 304 SS | 0.025" | View → |
| MS20995C32 | 304 SS | 0.032" | View → |
| MS20995C41 | 304 SS | 0.041" | View → |
| MS20995C47 | 304 SS | 0.047" | View → |
| MS20995CY20 | Cadmium-Plated Copper | 0.020" | View → |
| MS20995N20 | Inconel | 0.020" | View → |
| MS20995N32 | Inconel | 0.032" | View → |
| MS20995NC20 | Monel 400 | 0.020" | View → |
| MS20995NC32 | Monel 400 | 0.032" | View → |
MS20995 vs. NASM25173: what's the difference?
NASM25173 is the aerospace industry successor to the U.S. military standard MS20995. The Aerospace Industries Association (AIA) took over maintenance of the specification so that updates could be driven by industry need rather than the military procurement process.
The suffix system is identical: NASM25173C32 and MS20995C32 describe the same wire — 0.032" 304 stainless steel safety wire meeting the same tensile, elongation, and coating requirements. For most applications, the two are interchangeable.
When in doubt, check your engineering drawing. Some programs and customers specify which document revision and which spec number must appear on the material certification. If the drawing calls out MS20995, request a cert referencing MS20995 — and vice versa for NASM25173.
Frequently asked questions
What does MS20995C32 mean?+
Is MS20995 the same as NASM25173?+
What safety wire do I need for AN/NAS bolts?+
Can I substitute one alloy for another in MS20995 safety wire?+
Ready to order? We stock all the common MS20995 part numbers.
American Wire Works, family-owned since 1940, stocks the full MS20995 and NASM25173 safety wire range. Single cans, production spools, and mixed-alloy orders welcome. Browse our lockwire catalog or request a quote and we'll respond same business day.