When you're looking at belts, you typically think of them as a single item that you're purchasing, rather than a combination of a leather strap and belt buckle. This makes sense, since most belts are constructed by permanently sewing on the belt buckle to the strap, so you have a sturdy and reliable belt.
Chicago screws turn that whole idea on its head.
Chicago screws, which are also known as Chicago Fasteners, Chicago Bolts, Sex Bolts, Screw Posts, Tee-Nuts and Binding Posts, take the place of the permanently sewn on thread, and allow you to swap out different belt buckles with the same leather strap (or vice versa).
The Chicago Screw functions by having two threaded pieces with flat heads on both ends, so they sit flush against the leather of the strap, with one piece screwing into the other to create a strong, reliable hold on the buckle.
Since they are screws/bolts, it does take a couple of minutes to swap out buckles, as you'll need to take a screw driver to the screws to take them apart, so you won't want to leave this step until the last minute before you walk out the door. That said, it's worth the extra couple of minutes of time to ensure you have a strong hold on your buckle.
Some belts will use snaps in place of Chicago Screws, which may seem sufficient at first, but after use, the snaps will start to unfasten more easily, and you'll end up unfastening your buckle instead of unbuckling your belt, which should be avoided at all costs.
Chicago Screws are best used on casual types of belts, since they're typically wider and can accommodate the screws more easily, and having rivets or screws is more of a more casual look anyway. You also typically expect a dress belt to have the buckle permanently affixed and not see the hint of a screw or rivet underneath the overlapping belt when buckled.
Finally, if you're into cowboy or western belt buckles, then you should definitely know about Chicago Screws. Cowboy belt buckles are almost always purchased individually, and then a leather strap is added later, typically using Chicago screws (or if not, it should be). If your leather strap currently has snaps instead of Chicago Screws, then you really should think about upgrading to a more reliable fastener system.
At BeltCraft, we're excited about Chicago Screws and are going to be offering them as a belt add-on option very soon. If you'd like to add this option to a custom belt you're designing in the meantime, contact us and we'll let you know if they're available yet.