swordmaster,
Where are you located? I have noticed that there may be a language difference in some of your posts. Since you haven't filled out your profile, no one knows this.
Reamers are a different tool than broaches. Reamers are to enlarge a round hole. Broaches are used to cut a hole to a specific shape. There is rotary broaching and linear broaching. A reamer may be used somewhat similarly to a rotary broach, but there are differences in how it cuts and the shape of the tool.
The knife making "broach" that we refer to in slotting a tang hole is a broaching saw, which is a hand held linear broach. It is a small saw with back facing chisel teeth. You drill a hole ( or holes) in the wood, insert the broach, and cut by pulling the tool outward. A well made broach can slot a tang hole in only a few dozen strokes.
A lot of makers cut the slot hole using a drill press with a sliding vise, and good quality woodworking bits. Don't use your metal drilling bits for this task. Brad point bits are good for the task. The drills used to drill the holes in pen making are also superb, and longer than many standard bits. Finally, you can get a carbide tipped brad point bit in 1/4" for less than $20 that will drill tang holes straight and smooth for years without any problem.
Mark the tang slot on the handle block, and clamp in the X-Y vise. Position a drill bit the size of the tang thickness at one end of the marked slot, and lock down the vise slides. Drill the first hole to the desired depth. Unlock the slide and move the block to position the drill on the other side of the desired tang slot. Drill this hole. Now, move the block as needed to drill out the wood between the two end holes.
A side cutting reamer drill bit ( very similar to a rotary broach or side milling tool ) is good to clean up the slot after the holes are drilled. Most woodworking suppliers sell these bits.
If you try and use your regular drill bits to side-ream the slot, you will likely break a lot of bits. Just insert the rotary reamer/broach in the end hole, lock down the quill, and very slowly back the slide down the axis, cutting away the webs between the holes until you reach the end of the slot. To keep the slot straight and smooth, it is best to take smaller bites on the slot, say 1" at a time, than to try and ream the whole slot at full depth in one cut.
It is a good idea to cut the tang slot in the block before shaping the handle. The block is nice and square at this stage. The desired tang hole can be marked on the outside for positioning, and then transfered to the end in pencil. After the hole is drilled and broached, the actual tang position in the block can be re-marked on the outside, and the block band sawed or ground to the desired shape....leaving the tang hole exactly centered and where you ant it. If you shape the handle first, it will be nearly impossible to get the hole centered perfectly.
My advise to new makers ( and old ones who haven't figured it out yet) is to make the tang hole first, and then remove everything from the block of handle material that doesn't look like the handle you want.
