Military components numbers ID - list/data/system?

[Diabolical Artificer]

I come across NOS military components now and again in boxes or plastic packets with a number ID printed on paper labels. with resistors that's no problem as you can ID it from the colour code.

But especially with transformers you've no idea what the specs of the thing is, see pic. All you can as with all unknown tfmr's is do the usual DC res test to establish what windings there are, take an educated guess which is primary/secondary and put a signal in to get an idea of the turns ratio and bandwidth etc.

However, was there a central database that recorded the specs or intended purpose? How were numbers allocated, was there a logical system, or was it a case as with spy missions where there was a book of code names allocated at random? EG ABC123 was a wingtip for a Hercules, ABC124 a spare transformer for a radio intercom as used in the Captains bridge or suchlike?

Lastly, how the heck does one find said specs; are there online sources?

Andy.

[ms660]

That's a NATO stock number, aka nsn. Normally the internet won't reveal much.
Eg: 5950-99-946-7347

But 5950-99-946 gives the general sort of genre.

Lawrence.

[M0FYA Andy]

The '99' in the second field tells you that it is a British part.

The three forces had their own systems, which were subsequently replaced by NSN numbers. I'm much more familiar with the Air Ministry numbering system.

Andy

[G6Tanuki]

NSNs do tend to be of limited value in identifying old parts even if you have access to the index: once a part (and the equipment it is part of) is obsoleted - hence all the spares being sold-off - the NSN soon gets deleted.

[Strange-but-true: in the 1980s I had my own personal NSN!]

[Chris_A]

I don’t know if it will help but here’s a quick rundown on the construction of the NSN:

The first four digits are the Federal Supply Class (FSC) which is made up of the Federal Supply Group (the first two digits) and the Category.
Federal Supply Group 59 is - Electrical and Electronic Equipment Components.
Federal Supply Class 5950 is - Coils and Transformers.

Next two digits are the country of manufacture code; 99=UK, 00 & 01=USA, 14=France, 12=Germany etc.
The last 7 digits are the unique identifier, there are a number of national & international databases which may give more detail.

If the item was common and used across a range of equipment then it may have been manufactured to a Military Specification or a Defence Standard however if it was a component part, specific to one or a limited number of equipments, then the detail would probably be buried in the detail of that end item equipment and therefore difficult to find unless you know what the equipment is.
I’ll try and have a quick look to see if i can find anything when I get back from holiday but good luck with it anyway.

Chris

[Dave757]

Originally Posted by Chris_A

Next two digits are the country of manufacture code; 99=UK, 00 & 01=USA, 14=France, 12=Germany etc.

Chris

Hi Chris

I have a military CWC G10 watch NSN 6645-99-5415317.
However the watch is also marked Swiss made. Does the
99 perhaps also extend to items made abroad for the British Military ?

Kind regards
Dave

[M0FYA Andy]

I suggest 99 doesn't mean 'Made in Britain', it means 'Procured by/for the British Military'.

[Stockden]

Strictly speaking it means “codified by” (i.e. added to the inventory by) but the effect is largely the same. Once an item is codified by one nation it does not need to be recodified when it goes into service in another. Thus there are plenty of items in use by the UK armed forces that have 00 (USA) in the country field. Some of those items might have actually been designed and manufacturers in, for example, Israel but they were first codified with a NSN by the US.

As you rightly point out 99 absolutely does not mean “made in the UK” (though of course the item might actually have been).

[Diabolical Artificer]

It sounds a minefield and the chances of finding out the specs of my tfmr or other bit of a similar nature remote.

I presume somewhere in the UK and other countries there would be a central index library with all stuff the MOD/Pentagon/etc uses, must have been massive and a nightmare to impliment. I lose track of the components I have, which is minute in comparison.

Before computors I would guess the stores at base X had a record of what they had on a file index, must have took a small army of clerks to keep on top of it, and reams of paperwork every time a bit moved.

Andy.

[Station X]

I tried your transformer code here, but it doesn't say anything apart from what you already know.

https://www.nsncenter.com/NSNSearch?q=+5950-99-946-7347

I wouldn't expect to find detailed specs online.

[M0FYA Andy]

I can only draw a comparison with the Air Ministry numbering system, which started sometime in the 20's, and was subsumed into/replaced by the NSN system in the 70s, I'm not sure exactly when but it didn't happen overnight.
Any item needed by the RAF was allocated a Stores Reference number which was catalogued in A.P.1086. How many yards of shelf space this required as a paper document I dread to think. This was a 'living document', with entries added as new items were introduced, and entries removed as items became obsolete - pages were added or deleted by Amendment Lists, so any surviving copy is a 'snapshot' at a particular time.
In the early years, including the WW2 years, this document can be very helpful to us restorers 80 years on, providing, for example winding information for transformers. But it can be very inconsistent, sometimes providing no information at all on a particular entry.
At some point around 1960, A.P.1086 was reissued in a format which provides no useful technical information at all, not unreasonable as it assumed that if you were ordering something from the Stores then you knew what you wanted.
But fairly useless to us restorers and historians!
Obviously it was this format which then morphed into the NSN system along with the Army and Navy systems.

Andy