Brass book binding thingys

[John]

In the drawing office we used to put our A3 drawings into books having punched 4 holes. Through the holes and covers was a brass 2 piece clip. One half was a large flat head on a tube with an internal thread. The other half was a similar head but with a threaded stud. The two screwed together to hold the book together.

Now for the question - what are they called and where might I get something similar?

[fred]

In article , John writes

They appear to be called screw post binders, and the parts you mention binding posts and screws:

[John]

In article , fred writes