Carbide drill bits

[monty]

For drilling out your air holes, I haven't got these yet so I can't vouch for them but carbide is a deal harder than cobalt and doesn't blunt so quickly with heat. From Ali Express

[thatguy]

Have you checked the angle of these drill bits? PCB drills tend to be ground at 130-135 degrees whereas drillbits for steel are ground at 118 degrees. 130-135 degree angles are fine for cutting sheet metal but can shatter when faced with thicker sections, and the higher angle also makes centering harder.

These drills can get the job done, and done well, but a 118 degree angle would be easier to use for the inexperienced, or those using a cordless/hand drill rather than a drill press due to centring issues and the increased risk of the drill bit catching as it breaks through the material.

[GeoffUK]

Cobalts should last for ages. The trick is to drill very slowly, the heat build up tempers them and they go soft.
The trouble with carbides is they are very brittle and can easily shatter if you are not careful.

[Bobsbeer]

Having built my brewery out of stainless steel pots that needed about 5-10 holes in each pot plus other stuff, I can tell you, the best advice is to get the best quality drill bits for what you intend to drill. Buy cheap and you need loads of them, and you end up being very frustrated as they very quickly lose their edge. I have lost count of how many 2mm carbide bits I have snapped, using my hand drill.

[thatguy]

As a footnote, please avoid those drill bits you see advertised as Titanium, as it is merely a coating that will be lost after a little use. They are only good for a short time then they need replacing. As they rely on a surface coating they cannot be resharpened without a loss of performance. High speed steel drill bits are fine for occasional use, tungsten carbide drills, even better.

[tez]

Dormer for me

[decoy]

plasma cutter

[mart166]

With me it's bit one or other, I make clocks as hobby, for everyday stuff under 5ml tend to use cheap as chips generic bits, if they break no loss, for better jobs, eg a pair of hands that took 12 hours filling (my friend who gave me metal did not tell me it was HSS,) I invested in good colbalt bits, could not have faced a failure and all that work again.

MP