MIL-DTL-26482 Series 1 vs Series 2: What Interchanges
MIL-DTL-26482 is the most widely used miniature bayonet connector in industrial, rail, test-equipment and legacy aerospace wiring, and it exists in two series that are close enough to be confused and different enough to cause returns. Series 1 is the original solder-contact design, ordered as MS3110 through MS3116. Series 2 is the crimp, rear-release upgrade, ordered as MS3470 through MS3476. This guide covers what each series is, what actually interchanges between them, how to read both part-number formats, and the most common ordering mistakes.
Series 1: solder contacts, MS3110 to MS3126
Series 1 uses a three-point bayonet coupling, resilient inserts and, in its original form, fixed solder-cup contacts. The five basic shell styles are:
- MS3110: wall-mount receptacle
- MS3111: cable-connecting (in-line) receptacle
- MS3112: box-mount receptacle
- MS3114: jam-nut receptacle
- MS3116: straight plug
A second group of Series 1 numbers, MS3120 (wall mount), MS3121 (cable connecting), MS3122 (box mount), MS3124 (jam nut) and MS3126 (straight plug), covers the same shells fitted with front-release crimp contacts instead of solder cups. They mate with the solder versions and use the same accessory threads, but they need their own contacts and insertion tools.
Commercial equivalents: Amphenol PT (solder) and PT-SE (crimp), ITT Cannon KPT (solder) and KPSE (crimp), and others. Series 1 shell sizes run 8 through 24 in even numbers, and the numbers resemble MIL-DTL-5015 (MS3106-style) shell sizes, though the two families are unrelated and do not mate.
Series 1 class letters describe the rear of the connector rather than the plating. On Amphenol PT and the MS numbers that follow it: A is general duty with a threaded rear and no sealing grommet, E is environment resisting with a grommet and no clamp, F is environment resisting with a cable clamp fitted, and P is a potting version supplied with a potting boot. So MS3116F14-19P is a sealed plug shipped with its strain-relief clamp, and MS3116E14-19P is the same plug without one.
Series 2: crimp rear-release contacts, MS3470 to MS3476
Series 2 was designed as an upgrade to Series 1. It keeps the bayonet coupling and the MIL-STD-1669 insert arrangements, and adds rear-insertable, rear-releasable crimp contacts retained by a beryllium-copper clip, a closed-entry hard-face socket insert, an interfacial pin seal and a triple-rib wire-sealing grommet. Series 2 is also identical to the now-inactive MIL-DTL-83723 Series I, so M83723/1 receptacles cross to MS3470 and M83723/13 plugs to MS3476.
- MS3470: narrow-flange wall-mount receptacle
- MS3471: cable-connecting receptacle
- MS3472: wide-flange wall-mount receptacle
- MS3474: jam-nut receptacle
- MS3475: straight plug with RFI grounding spring
- MS3476: straight plug
- MS3479: hermetic jam-nut receptacle
Contacts are M39029/4 pins and M39029/5 sockets: /4-110 and /5-115 in size 20, /4-111 and /5-116 in size 16, /4-113 and /5-118 in size 12. Insertion and removal use the plastic M81969/14 tools. The specification rates the standard MS3476 plug for 500 mating cycles and the RFI MS3475 plug for 250.
The current Series 2 class letters are about material and finish. A is aluminum with black anodize, L is aluminum with electroless nickel, and W is aluminum with olive drab cadmium over nickel. Classes A and W are rated for 500-hour salt spray and L for 48 hours. Older drawings still call out Series 2 class E, and sometimes F, P or R; E and R were superseded by L, and any legacy letter should be checked against the current slash sheet before quoting. Aero-Electric AE3470-series numbers are the Conesys commercial equivalents.
What actually interchanges
| Item | Series 1 (MS3110-MS3126) | Series 2 (MS3470-MS3479) | Interchangeable? |
|---|---|---|---|
| Coupling | Three-point bayonet | Three-point bayonet | Yes: same shell size and arrangement intermate across series |
| Insert arrangements | MIL-STD-1669, 8-2 through 24-61 | MIL-STD-1669, 8-2 through 24-61 | Yes: same face layouts and polarization |
| Contacts | Solder cup (fixed) or front-release crimp | M39029/4 and /5 rear-release crimp | No: different contacts, retention and tooling |
| Rear accessory thread | Series 1 thread family | Series 2 thread family (shared with 83723 Series I) | No: backshells and clamps are series-specific |
| Protective covers | MS3180 (plug), MS3181 (receptacle) | MS3180 (plug), MS3181 (receptacle) | Yes: covers fit the mating face, which is common |
| Jam nut | MS3186 | MS3186 | Yes for the nut itself; confirm panel cutout |
| Class letters | A, E, F, P (rear style) | A, L, W (finish) | No: different meaning; do not translate letter for letter |
| Contact sizes | 20, 16, 12 | 20, 16, 12 | Yes: same current ratings |
The short version: a Series 1 plug will mate with a Series 2 receptacle of the same shell size, insert arrangement and polarization. What you cannot do is use Series 1 contacts, contact tools or backshells on a Series 2 connector, or the reverse. The bayonet interface is common; everything behind the insert is not.
Part-number anatomy
Series 2 example: MS3476W16-26S
- MS3476: straight plug, Series 2.
- W: class, aluminum shell with olive drab cadmium over nickel.
- 16: shell size.
- 26: insert arrangement, 26 size-20 contacts in a size 16 shell.
- S: socket contacts (P for pins).
- A trailing W, X, Y or Z indicates an alternate insert rotation. No letter means normal.
Series 1 example: MS3116F14-19P
- MS3116: straight plug, Series 1, solder contacts.
- F: class, environment resisting with cable clamp.
- 14: shell size.
- 19: insert arrangement, 19 size-20 contacts.
- P: pin contacts.
- Same rotation suffix convention: W, X, Y or Z, or blank for normal.
Insert arrangements are written as shell size, dash, layout number, from 8-2 (two size-20 contacts) up to 24-61 (sixty-one). The layout number usually equals the contact count, but mixed layouts such as 12-8, 14-12, 18-11 and 22-21 combine contact sizes, so quote the arrangement exactly as drawn.
Accessories: MS3180, MS3181, MS3186 and backshells
MS3180 is the protective cover for plugs and MS3181 the cover for receptacles, ordered by shell size, attachment style and finish. Because they cover the mating face, one cover part number serves both series. MS3186 is the replacement jam nut for MS3114 and MS3474 jam-nut receptacles; the Series 2 drawing calls out its thread directly.
Backshells and cable clamps are where the series diverge. The rear accessory thread on a Series 1 shell is not the same as the thread on a Series 2 shell of the same size, so a strain relief bought for an MS3116 will not run onto an MS3476. Series 2 shells share their accessory thread with the old 83723 Series I family, and M85049 backshells are listed against Series 2 by shell size. If the drawing gives only “with clamp”, ask which series before quoting the clamp.
Common ordering mistakes
- Ordering MS3476 contacts for an MS3126. Both are crimp, but Series 1 front-release contacts and Series 2 rear-release M39029/4 and /5 contacts are different parts with different tooling.
- Assuming class letters translate. An MS3116F is a sealed solder plug with a clamp; there is no equivalent “F” in current Series 2, and an MS3476W is a plating call-out, not a clamp call-out.
- Reading 26482 shell sizes as MIL-DTL-5015 sizes. A size 14 MS3116 and a 14S MS3106 are unrelated.
- Quoting by contact count instead of arrangement. “16 shell, 26 contacts” is enough for a stock check, but the layout number on the drawing is what must appear on the certificate.
- Dropping the rotation suffix. 14-19PW and 14-19P will not mate with the same receptacle.
- Ordering a backshell for the wrong series, or ordering an MS3475 plug when the drawing shows MS3476. The RFI spring changes the plug length, the accessory interface and the cycle rating.
- Substituting Series 2 for an obsolete Series 1 number without checking the accessory. The mating side will work; the clamp may not.
Which one should you specify?
For new work, Series 2: crimp rear-release contacts are faster to terminate and repair, the sealing is better, and the QPL base is broad. Specify Series 1 when you are matching an installed solder interface and the rear hardware must stay the same, or when the drawing calls MS3110 through MS3126 and you cannot change it. Either way the connectors mate across the series, so an MS3476 is a legitimate replacement for an MS3116 plug as long as its backshell and contacts are ordered for Series 2.
Newcastle Industries stocks MIL-DTL-26482 Series 1 and Series 2 in Los Angeles, including MS3110, MS3116, MS3470, MS3474 and MS3476 shells, M39029/4 and /5 contacts, MS3180 and MS3181 covers and MS3186 jam nuts, with same-day will-call. Send the drawing part number and we will confirm series, class and accessory fit before quoting.