Third video - perfect.
A centre-punch hasn't been mentioned yet, but is important, especially when drilling metal by hand. The tip of a drill bit isn't pointed, it has a tiny flat spot left behind in sharpening. This can cause the bit to skate over the surface when you're trying to start your hole. The answer is to centre-punch your spot so that the flat tip of the bit can locate itself in the dimple and stay there. On metal, you need a proper hard punch that can take a hammer hit like this:
On wood, the same punch will work, but i prefer to use an awl and press it in by hand:
Soft plastics can benefit from either of the above. On hard plastics the metal punch could crack the plastic and the awl might not go in far enough, but starting with a small drill or centre-drill should be pretty easy without a punch mark.
~ Centre punches are really a lathe tool, but they can make life easier for drill press or hand drill users. The reason the short, rigid centre drill is so important on a lathe is that you can't centre-punch the exact spot, so you go with the super rigid bit that can't be flexed and pushed off-centre by the tiny bumps and ridges in the work piece. You just need it to "spot-drill" as in Video 3.
~ Then you can go with a small pilot drill - I usually use 3mm or 1/8" - followed by your final size.
~ If you're drilling bigger than 3/8" or 10mm, the flat tip may be bigger than your pilot hole, so an intermediate hole half-way between your pilot and final sizes would be a good idea.
~ Don't forget to peck-drill as per Video 3. This is the key to clean holes.
~ If you're drilling right through your piece, have it pressed flat against another sacrificial piece of wood, which you can drill right into. This will help avoid the underside of your workpiece from chipping out.
NB, these tips are with regard to normal conical tip twist drills. Brad point drill bits and Forstner bits don't need pilot holes in most cases.
Edited by ash, 22 June 2013 - 01:46 AM.