In one of the "Blacksmithing with Hershel House" dvds he demonstrates forging and assembling one of his "backwoods" style antler handled knives.
He drilled the antler with a hand held electric drill from each end until he felt the holes meet, then he bent the knife's tang cold in his hands, to fit the antler's curve.
I think,if i remember right , he said the tang length 1/8" above the washer. He picked a drill bit slightly smaller than the tip of the tang and drilled the cap, kind of a washer looking styled one in this case, then filed a square or rectangular hole that fit the tang tip VERY snuggly, he stressed a nice perfect fit here. (he had already, after forging, fully annealed the entire blade and tang so it would be as soft as possible)Then, after filing to refine the blade shape, hardening and tempering the blade but with the tang still fully annealed, the knife with handle and cap in place, held in a vise, and a medium sized ballpein hammer, using the ball pein he lightly peined the tang, while it was cold, not heated.
The thing that impressed me though, was the amount of drawing out of the steel to make this thing. He took a piece of antique buggy spring that looked like maybe 1/4 to 3/8" thick and, while hot, hardied and chiseled it to a kinda stubby triangle, then chiseled two cuts out of one corner to make a stubby tang, then with a 2 pound cross pein hammer drew out, way out, the blade and tang to length.
I think i'd do a trial mock-up in a vise for peining practice on a tang like piece of steel and cap to be sure the 1/8" was enough or not too much length though.
john