This Mosda clipless paper fastener is one of a large number of machines designed to attach sheets of paper together without the use of external materials. They date from the early years of the twentieth century and are often referred to as stapleless staplers. These are admirably simple and efficient machines.
My machine was made in England, and  looks like it is from around 1930. The Early Office Museum has some great information on the history clipless paper fasteners, unfortunately it does not record the cutting patterns of the machines, which is necessary to determine what particular machine was used. The wonderfully detailed blog, The American Stationer, examines a number of paper fasteners, but not the Mosda. Except for a couple of ebay and etsy sales, I’ve not found much info about it, other than an almost exact copy ( maybe the original?) machine called the Chadwick. (Fig 2.)
According to the Early Office Museum Website, machines for stapleless paper fastening started in 1909 by two competing firms, the Bump Manufacturing Company and The Clipless Paper Fastener Company.  There is some confusion as to which company came up with the first machine. Yet even today, you can buy a new Japanese machine,  which uses almost the exact same punching configuration, though in tandem.
The mechanism is quite ingenious, and even though this machine is very well used and the blades slightly dull, it still creates a surprisingly secure paper attachment with a single push on the top knob. My machine is missing a spring under this knob, so I need to manually lift the knob back to the start position before making a new attachment.
First the stapler punches a “U” shape and a small straight line behind it. For clarity, I am showing the mechanism on the bottom of the machine. In use, the paper is inserted in the slight gap between the bed and the half arch head as seen in Figure 1.
Next, a tongue pushes the attached tab of paper from the  “U”  punch through the slit. This is then raised to the top of the papers, securing them. Other manufactures report that six to twelve sheets are the maximum number that could be punched through, though of course this depends on the thickness of the paper. I’m pleasently surprised this machine works so well, as can be seen below, considering that the punches are unhardened pressed steel.
Examining these stapleless fastenings could even generate useful information, such as establishing the  terminus post quem a stack of sheets were assembled. With such obvious tool marks, I imagine it wouldn’t be too difficult to get a sense of a range of shapes and match them to extant machines. Or maybe these antique machines still have uses for the inventive book artist, like non-adhesive corner locking for limp structures?
Peachey Conservation 
The Mosda and Chadwick were out at the same time and are the same machine. They were out in the late 60’s through mid 70’s. Note also the Grant’s Miracle Paper Fastener which again is the same machine but with a lever handle instead of a plunger knob. There were at least a half dozen companies that sold these Grant-type fasteners under their own name. They were all made by the same Japanese company just under different names. The only sort of exception was the Mosda which was made in England but under Japanese specs.
Thanks for the info!
Thanks, Jeff. Makes me think of Jana Dambrogio’s research on letterlocking. http://www.janadambrogio.com/formattimeline-2/
I also thought of that, though these machines are more “sheet-locking” in the sense they hold the leaves together while making the information accessible, as opposed to most letter locking mechanisms that also keep a record of if the information is accessed, because they are usually altered when the letter is open. Maybe Jana can correct me!
Jeff, can’t resist a related (sort of!) anecdote… sometime in the 1980s or early 1990s my predecessor here at Iowa, Robert McCown, has the genius to mount an exhibition on paper clips. He went to considerable effort to round up, from varied sources, a considerable assortment of examples — collectively testimony to the human ingenuity invested in this simple device!
I don’t believe the exhibit captions were saved — at least I can’t recall ever running across them — but the collection of clips was still kicking around when I retired three years ago. It was a bit of annoyance because Bob had found a giant clip, 30 inches or more long, that resisted any of the standard forms of “shelving” (a subject on which there is at least one quite good book). The Big Clip took up as much space as the rest combined.
My favorite was a round clip, a spiral really, the inner coil(s) of which could be pushed up (or down) so the outer coil could be slipped over the edge of a sheaf. This design put a limit, of course, on how thick the sheaf could be, but its beauty was that the clip was flat and only a few millimeters thick. It thus largely avoided the problem of “added thickness” that quickly generates when you pile several documents all clipped in the upper left corner atop one another!
Ever since I read Petroski’s “Evolution of Useful Things” I’ve at least saved interesting paper clips I’ve run across, though nothing as unusual as the big clip. Love to see images if you have any.
OMG you have one! The only metal-free staplers I can currently find are a feeble copy of this stunning machine. As a book artist I don’t really have a specific use for this, just think it is so very clever!
Not to rub it in, but I paid $8 for it this weekend at a flea market in Manhattan! I did see records on ebay etc. so it looks like they pop up at least occasionally. You also might ask the collector who runs the “American Stationer” link if he has dups.
I inherited a Bump model that is combined with a round hole punch, marked “Patents Pending,” which (according to the “clipless paper fasteners” link you give) dates it pretty tightly to 1917-1918. It works great for three or four sheets, but there is definitely a limit to its capacity. Even an ordinary stapler will securely fasten a thicker block of pages. Also, although you can undo the pages, add more, and re-fasten in another place, the accumulated damage is greater than a stapler would cause. I’ve used mine a fair amount on and off over the years, but I usually end up back with staples because of the capacity issue.
Some new research here: https://americanstationer.wordpress.com/2016/02/25/mosda-clipless-paper-fastener/