Hi Muggs
Before cleaning try to hold it up at a flat angle to your light source and see if there is a "shadow" or stain from any inked on part numbers. Hard cleaning would remove most shadows/stains tho is necessary for stamped numbers.
Even a partial part number is a great help - especially the first 3 or 4 characters.
If you know any police who work with finding serials on stolen cars etc they may be able to tell you the common chemicals that highlight such marks. It is thirty years since I did that and I cannot remember what we used.
Another help would be material thickness's if you have a sheet metal gauge or an accurate micrometer available (verniers tend to provide inaccurate readings if you are unskilled in using them on sheet). Bolt hole sizes given the overall condition are probably not going to provide much help and the one visible screw and nut remaining is probably too far gone to use to check the thread
American sizes for sheet-metal are sizes like 025/032 etc.
The English use sizes that include some US sizes but also use odd ones like 028
The Europeans as far as I know use metric thickness's
Hi Flyboy.
Great idea to try and find manufacturer specific fasteners. I know Curtiss and Bell were into some oddball stuff (Curtiss with their 78 degree heads and "1/2" length rivets on the N model - did save a lot of weight tho) however I have never heard of Consolidated doing so - that most definitely does NOT mean it did not happen tho.
The use of a fabricated frame when Consolidated used mainly or exclusively hydroformed frames speaks against it being B-24 or from a major American producer but we must also consider that this may be from an older design of US equipment or it may be from a vendor component such as a turret or other weapons system or some radio equipment. From the size and outer skin (see below) I doubt it but that is only a personal feeling
Of general interest
on the technical side is that the door latch assembly uses riveted countersink tails on the rivets. You will note the factory formed dimpled rivet heads are on the inside and this means the countersink "head" on the outside is actually the rivet tail. This is an time consuming way of manufacturing not normally used in rapid mass production as the tail must then be machined flush with the outer skin after the riveting is complete. The up side is that the skin is aerodynamically perfectly smooth so there is a performance benefit in making a skin this way. Hopefully this might give Airframer an idea (but then again it may be British, and, as the old saying goes there are three ways to build an aeroplane - the right way, the wrong way and the British way. The corollary to that is that the British reportedly only had one design rule - Wy make it easy when with a little bit of thought you can make it bloody near impossible).
The other technical oddity is that the thin outer skin is machine countersunk when normally by WW2 in the US at least all thin skins using countersink rivets were dimpled. Thin machined countersinks are prone to pulling the head through sheet as is evident in many places on this component.