There are 3 types of rivet type fasteners. Cutlery Rivets, which I see on a lot of machetes. They consist of a solid male and hollow female bolt. To fasten on a handle, you drill the proper sized hole for the bolt and then pound the male rivet into the female. They are soft, so the male spreads and locks inside the female to hold the scale on. The next two are the corby fasteners and the loveless bolts.
The corby's also consist of a male/female section; but in this case the two are screwed together. You need to drill a hole the size of the shafts, plus another counter sink hole for the fastener heads. The loveless bolts are similar to corby's but consist of a machine screw and two hollow nuts. The machine screw goes through both nuts(one on each side of the handle and is tightened down. It required a special step drill available from knife supply catalogs; in fact they carry step drills for both loveless and corbys. Once the bolts are in place they are ground down flush with the handle. Standard straight pins, i.e. 1/8" 1/4" etc can be fastened two ways. One way is to cut the pin slightly larger than the handle thickness, place it through the pin hole so a little of the pins shows on each side and then peen the bit of pin showing down. You have to be careful that you don't peen too much or that creates pressure on the handle material, which eventually crackes. In the other method the the handle slabs are epoxed to the tang and then pins can be held in place by further epoxy through the pin hole or by doing the peening thing...or both.