Mystery File Help

[Cleave]

Here's an old Nicholson file I got a while back, probably $1, looks unused.
The cross section is shaped more or less like a knife, but the grind looks "factory" that is, I don't think its someone's half finished project.
ALL faces and edges are smooth (no file teeth) except on the wide side (back of the knife if it were one), the half closer to the tang has file teeth. The teeth are only between the two nails in the first image.
I have and use a lot of files and have no idea what this is for. My only guess is the "sharp" edge could be used as a metal scraper inside a big bearing housing and the file part could be used to dress the bottom of a keyway without affecting the width...
Any other guesses?
This one isn't a saw set or a leatherworking tool.

 

[leg17]

The general shape is indeed a 'knife' file, but I am not familiar with this particular configuration.

 

[RTM]

From a Disston publication, for those interested.

Knife File
—Tapered from safe back to filing edge, and from **** to point. Similar in shape to a knife blade. Made *******, second cut and smooth cut. Used for filing in V-shaped slots, principally.

No idea on the weird safe sections. I'm assuming you would have told us if someone had ground the edges safe, vs being a factory special order.

The slight curve on the back would require an interesting surface, to be sure.

 

[RoninB4]

-Can't offer a definitive explanation on application but I have had numerous files with selective inclusion/omission of file teeth. Many times, before the days of WEDM and 5 axis CNC, mold details would have to be created/finished with files where there was only ONE surface needing metal removal. Keyways could be another application with similar requirements. While files like yours were not part of the standard production line they were available in a multitude of configurations for special/custom order. Why the knife shape? Hard to say but it may have been the cheapest shape readily available that would have teeth on that side. I have files with selective teeth sides but they're much smaller than yours, which is one of the largest selective teeth files I've seen. At one time a file blank (soft state with no teeth) could be ordered, I have one that's about 12" long. Long story on file making with centuries of model variations, yours is an interesting example even if it's not very useful to you.

 

[Beerhippie]

Are you sure that's not a saw set?

 

[four.cycle]

"joint file" ?


1954 Nicholson file catalog pp 53

 

[alwaysFlOoReD]

"joint file" ?


1954 Nicholson file catalog pp 53

No knife edge.

 

[Beerhippie]

No knife edge.

Nor clipped edge.

 

[Private Lugnutz]

Any other guesses?

As @leg17 first identified, it clearly has the profile of a knife file. My immediate thought was an "unfinished" or incomplete version of a knife file (i.e., one that was forged and then taken off the line before any cuts of any kind were put on either side). As the catalog excerpt @RTM provided above indicates, Nicholson knife files came in "*******, Second Cut, and Smooth Cut". His particular excerpt didn't include this, but they came in OAL's of 4, 6, 8 and 10 inches. For decades. As for the section with cuts on the back, many Nicholson catalogs state, "Backs uncut but cut backs supplied at customer's request at no extra charge." I suppose it's possible a customer had a very unique use, perhaps the acute angle scraping or very fine burnishing you theorized yourself, and ordered it completely uncut except for that section on the back, which may have been used for abrading, just like some special shears and snips that comes with blades with a small serrated section on the back.