what do you call it

[BobL]

Small (usually brass) clip/pin for holding papers together.

They have a small mushroomed head like a small button and the pin is about 3/4" long, flat and splits in half.

After the pins are poked through a hole in paper a washer is placed over the pin and then the pin is split bent apart.

Danged if I can remember the name!

[BMKal]

I've only ever seen them referred to as paper fasteners / metal paper fasteners / brass paper fasteners. Google any of these and there are plenty of choices.

[Bohdan]

Esselte paper binders.

[Tonyz]

Esselte paper binders.

move to top of the class, dont take your books though, you wont be there long........................

[BobL]

Thanks everyone - they're exactly what I want - I only want 2 but it looks like I have to buy 100!

[GraemeCook]

They are ubiquitous in any office, Bob, although zinc plated are far more common than brass. Every file in every filing cabinet has at least one.

They come in lengths from about 12mm through 50mm. That washer almost always gets lost after three or four additions to a file. Usually, they come in boxes of 144 or 100, but most stationery stores will have smaller packets. Next time you are in an office, just ask, they will probably give you a handful.

They have a range of names including file pins, filing pins, split pins, even bodkin pins. For non-office types, a bodkin is the awl used to poke holes in papers prior to filing on a file pin in a file cover.

[BobL]

I got some from office works $5 for a packet of 120. They did not come with washer

I only needed 3 and this is how I used them

This is my 3D printer enclosure and it's lined with 1mm polycarbonate (PC) on an extruded Al frame.
To reduce heat loss the PC is insulated with Aluminised plastic film on black core flute - some plastics are best printed with the inside of the enclosure at 50ºC.
To look inside while its printing without opening the door I cut a U shaped view port flap (H) in the core flute and using wire marked by the green arrow I can lift the flap up
sealedenc2.jpg

On teh other side this is what it looks like.
The binders are used to hold a soft sprint in place to return the flap to the closed position, and one is used to attach the pull to open wire

sealedenc3.jpg

After doing this I have thought of a more elegant solution.
I will make a up a small panel of aluminised core flute and hold it in place using a pair of magnets, one taped to the core flute and the other taped to the inside of the view port.