At a flea market in Maine, I was looking for rusty plane blades for my experiments on rust removal (VERY challenging to find it seems). I came across a pile of rusty things, most too large to do anything with – but I bought a rusty plane for $1. The only thing I was certain was that it was a Stanley excelsior of some sort.
The plane is coated in a layer of rust, to the extent that the rust has prised off the japanning. There are no parts missing from the plane, although there are some nicks, and rough edges. The adjustable mouth has seized to the plane body. The plane is 7″ in length, and has the characteristic “excelsior” hump towards the rear of the plane – all the hallmarks of the Stanley No.15.
Plane markings for identification
On further investigation, the plane has three identifying markings (readable through the rust): patent markings and the STANLEY trademark on the lateral adjustment lever (76, 84, 88, 88), an “S” owner’s mark on the side of the plane, and an “S” foundry mark on the bed, posterior to the mouth (so faint I couldn’t photograph it properly). Using the block plane dating table on the Virginia Toolworks website, it is likely this plane dates from between 1889 and 1897. As the No.15 is similar to the No.9½, to which the adjustable throat was added in 1897, I would say the plane is of that vintage.
Exploration of the rust
The task now? Disassemble it and dunk it completely in Evaporust to remove the rust – then likely a repainting of the japanned areas, and lapping of the areas that should be “shiny”. It will never be a perfect specimen, but it might function again.
working by hand 
Looks like a fun project. The S stamped onto the side is unlikely to be a foundry mark, even though the plane dates correctly for that stamp. I’ve never seen a foundry mark on the cheeks of a plane, always on the bed. The S on yours is most likely an owner’s stamp. It was common practice for journeymen of the day to stamp their tools, and many used manufactured steel stamps to do so.
There is another “S” on the bed, just rear of the mouth. Is there a specific area the foundry mark would be?
thanks!
Rear of the mouth on the bed is the proper location of the foundry mark. Gotta love those Excelsior planes. I wrote a post about them on my blog – Virginia Toolworks
” the rust has prized off the japanning”
The word you want is “prised”