In Chicago screw binding, loose sheets are collated together to form the book block. Two to three holes are drilled, evenly spaced, along the spine side about 1/4 inch from the spine edge. (Think of a stack of 3-ring binder paper.)
A barrel post is inserted into one of the holes, and the slotted cap screw is screwed into the barrel post by hand. A final tightening of the slotted cap screw is done with a tool that looks like a flathead screwdriver.
Typically, the barrel post will be positioned on the bottom, and the slotted cap screw visible from the front of the book, making for a great industrial look.
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