I have done a few but find it a lot easier, quicker and less troublesome to buy predrilled handles.
Cut the handle a little longer and wider than you need, I think I used 20 X 2, make sure it is square, mark the center of both ends with a center punch.
Now make a second handle out of some scrap hard wood the same dimensions as your handle blank, this will be the guide for your bit. Cut the guide in half lengthwise, cut a groove half the diameter of your bit in each half, I used a table saw and the groove was square but I guess you could use a router or shaper. Anyway the bit should fit snugly between the two and be right in the center.
Clamp, the blank in a piece of angle iron. I used a piece of aluminum angle that was square on the inside so the blank fit it perfectly and four clamps at right angles to each other. Now clamp both pieces of the guide to the angle about an inch or so from the blank. Lock the whole thing in a vice.
When the bit is inserted the point should hit right in the center mark. Drill very slowly, back the bit out after each 3/8 to ½”, keep the chips cleaned out. You can try drilling the entire length or you can drill half way, turn the blank around and drill the other half, just make sure you keep the same faces against the iron.
I made a bit out of drill rod, it was shaped like a standard spade bit. Only make it as long as you need.
I did a few but not all were successful.
Tim C.
Notes:
Things Have to be square, Not just almost but Square.
There can be no play between the bit and the Grove in the guide.
Run the drill slowly, let the bit do the work, Do Not force it, back it out and blow the dust out often.
The bit should be polished smooth use some bees wax as a lubricant and put more on during the drilling.
Lube the groove in the guide also.
You may be able to get by with a guide that is shorter than the blank, I just felt more comfortable with it being
long. Also if it is shorter you will not need as long a bit.