WD40 has for decades, been considered to be a 'toolkit in a can' to do lots of things, not of them particularly well, (notably as a penetrant and lubricant), but WD40 (The company) does have a 'specialist' range, which includes cutting oil:
I'm well aware that there is now a 'range' of products but there is a tendency for too many people quoting 'WD-40' as a panacea without referencing the specific product which usually means that they are talking about the original.
Yes we really never do stop learning and it is for me very enjoyable. Only last year on a speed awareness course I learnt what a dual carriageway is after forty plus years of driving, amazing. I had always thought of them as anywhere you have two or more lanes in the same direction, not the case and for those not in the know there needs to be some form of central barrier between the two directions of traffic to keep them apart. The tutors way of remembering this was just to think if you could roll a ball from one side to the other without obstruction, yes some smart rear ends will just say what if it passes under the armco but the tutor pointed out it was a large ball !
odd that he felt to patronise with the example of a ball, how about 'is there a barrier and more than one lane'?
so if you were to remove the need for accuracy (for a rough project say), you'd just go straight in with a big bit, no pilot, no punch?
I think he was amazed when he realised how few of us could define a dual carriageway, few got the speed limit right and some even stated it was where you can go fast and overtake the slow coaches. The idea of rolling a ball did hammer home the true definition and another one is NSL, no street lights or national speed limit and it must have worked as I now remember them. Perhaps it was much easier forty plus years ago to pass the test !
The reason for pilot drilling is to be large enough to cover the web of a large drill bit making it easier to drill through/into material. The web is the part between the two cutting edges, and is right in the centre of the drill bit and does not cut the same as the two cutting edges meaning more force is needed to push the bit through
I would always use a centre punch or something to make an indent. The rest depends what you are drilling and the size. For thin sheet metal then a hole saw or flycutter and you could just drill a hole without a pilot if you are not looking for accuracy, as I said for precise location use an optical punch.
Easy way is to use a rod with an angled tip on it the same size as your pilot drill, transfer punches are good. Drill pilot hole, lower table, insert rod of a similar length to your next drill in chuck then lower into your hole and position the table so the rod enters the hole cleanly without deflection, then tighten the table. By moving the quill up and down you can easily see if the rod is going straight in or slightly off. With a bit of practice you can do the same using the tip of the larger drill. This of course assumes that the work is secured to the table in a vice, so it is only the side to side positioning you have to worry about. I generally use a 6mm pilot drill and have a 6mm rod about twice it's length. Not of course super accurate, but good enough for most purposes. If you want super accurate then you need a mill.
What's the benefits of stubby drills?
They're shorter, so less likely to wander.
That's a very important consideration for @bertterbo
