Like this rivet that has tooling rings in it. [img]http://www.cox-internet.com/halberds/rivet.jpg[/img] I don't think the old ones had this industrial finger print in them, do you?
It's time for some grinder magic a light touch with the angle grinder and after that some very light hammer strokes, just to make it more handmade like.
Generally, I heat them to a red with a small propane torch, pop them in a header, tale a ball peen or high crowned hammer and whang them into a rose-head or other desired design. Other methods may be faster, but this feels GOOD!
There are rivets known as truss head rivets that have a smooth,low dome to the head. you may want to try those.
------------------ Captain Jamie-a marvellous valorous gentleman, that is certain Failure is the price of knowledge Changing the face of warfare one weapon at a time