The last part is kinda confusing, but maybe you're talking about Loveless Bolts? They're made up of a machine screw with two hollow, threaded, slotted nuts. Basically, once you use the screw head to tighten everything down, the screw head gets ground off and the bolt on the other, and you have two nuts with "bullseyes" showing. Another type, known as Regular Bolt sets consist of a screw type with one hollow nut, the other solid and part of the main screw. When you grind them you get the solid head on one side of the handle and the "bullseye" pattern on the other side. Might be what you talking about. Never used them, 'cause I like the "Double Bullseye" effect I get from the Loveless bolts. There's also Corby bolts and Acorn bolts which consist of of machine screws with partially threaded, solid nuts that leave a solid appearance when ground. You need a step drill of the proper size when using any of these type bolts. All the major knife catalogs carry them(bolt and drills) such as Sheffields Knifemaker's supply or Texas knifemaker's supply, K&G etc. If you're talking about some other kind of fastener, I can't quite picture it from your description.
