Archimedes drill

[bustagasket]

omg this site deteriorates so much!

[Coco]

I found an old mini rotary tool in our garage and that takes ages to drill through copper too. I've tried it with various drill bits and they all take ages. Do you think one that does more rpm would cut quicker or do I just need better quality/sharper drill bits?

[Boo]

I saw this earlier and wanted to reply, but dinner was ready and I also wanted to actually try drilling a hole before commenting.

It really depends on how thick your copper is, you haven't said what you're drilling and what you hope to achieve, so it makes it hard sometimes to give a precise answer - the answer ends up in general terms.

When I'm drilling holes in hammered bits that are something like 0.5 - 0.7mm thick, a rotary tool goes through in a couple of seconds. I tend to clamp the metal against some scrap mdf and drill into it - for safety and a better quality hole. I stop when I see sawdust.

You need to punch a mark with a centre punch first so that your drill doesn't scoot over the surface and it gets a good start and drill perpendicular to the surface, not at an angle.

Your drill bit needs to be sharp (and the right sort/shape) and as already mentioned, a hole started smaller and working with a progressively larger bit is better than trying to make one large hole with one single bit the right size. Metal drilling needs lubrication ideally, but for the modest holes I've done in thin metal it just hasn't been necessary - I'm through before the bit gets too warm.

I have several rotary tools and the one I prefer for drilling, because I prefer the shape of it in my hand, is the slowest, I actually prefer it not to go too fast. But I suspect if I want to go through thicker metal I'll need to use something with more muscle - or work in short bursts with lubricant. Steady on Geti.

I just tried a couple of 1.5mm holes (the size I'd do to thread earwires etc.) in some 0.5mm thick copper and used my favourite little rotary tool with a 1.5mm high speed bit. I did 2 holes, one at the slowest speed of the tool and another at the fastest. The slow one was through in about 3 seconds (by which time, I'd gone 3mm into the timber too) and the fast one in half that. You're through the hole and realise that you are and stop the drill in a flash. I don't think I could actually start and stop it again any faster than that.

So if you're only drilling thin sheet and not getting through straight away, maybe your drill is either wrong on blunt. This same rotary tool has a habit of the drill not always running true - it spins with an elliptical axis - so I always look at it spinning against the light to check it's straight - tonight it was spot on first tightening - other times I might need to undo and re-fasten the chuck several times to get it truly running straight. If it isn't straight, it won't make a good hole at all.

I've only done a modest amount of drilling in metal - so not terribly experienced, so others may be able to offer more help. I've just stuck with what has worked for me.