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I have been led to believe that it is very important to the performance of the job and the life of the bit to use the appropriate speeds, etc., when drilling various materials.

I was about to purchase an expensive drill-bit set -- which also advised a very simple (and I need simple) guide for drilling. Problem is that when I looked at reviews it is clear the bits I was going to buy are absolute crap. This makes me question the guide, although I'm hopeful I can still use it (i.e., put it in my "workshop" as a reference for when I do drilling).

Is the following table reasonable -

Material Pressure Speed Coolant
Glass Light Medium Water
Brick Medium Medium-low Water or Air
Concrete Medium Medium-Low Water or Air
Steel Heavy Medium Air or Oil
Aluminum med-Heavy High Oil
Wood Med-Heavy High Air
Ceramic Light Medium Water
Plastics Med-Heavy Medium-Low Water or Air

(Ignoring purchasing the most appropriate bit for the material), does the above guide only apply to all bits, or only the bit in question which is described as "Chrome Vanadium Shank, Titanium and Tungsten Tip".

Relatedly, there is a disclaimer that the bits I'm not going to buy are not designed to work with the drill's hammer function and should be used in regular mode even for masonry and concrete. Assuming I get a separate set of concrete bits, does the pressure, speed, and coolant apply to those bits as well?

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  • missing column ... type of bit ... bit material
    – jsotola
    Oct 13, 2021 at 4:48
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    For most, it makes little sense to invest in expensive bits where half the set has never been used 5 years later. Buy a cheap set and after a while replace the worn ones (your popular sizes) with better bits. Otherwise you'll end up babying them and taking longer than you need to get the job done.
    – dandavis
    Oct 13, 2021 at 6:58
  • @dandavis I more-or-less agree, but I have identified 6 bits I use regularly (and blunted 2 of them in the space of 3 holes, because they were the wrong tool, and I likely drilled them wrong) - so there is not much difference between getting a good set and the individual sizes I need. The question is do the techniques work across all bits (of-course, more appropriate bits will last better), and are the techniques roughly as per the above chart?
    – davidgo
    Oct 13, 2021 at 7:09
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    These seem like fairly universal recommendations; however, I would add that because "pressure" and "speed" are subjective, keep these thoughts from a mentor of mine in mind: "if you are trying to push your way through the material, throw away the drill bit now and get a jackhammer", and "high speed does not mean light-speed..."
    – Jimmy Fix-it
    Mar 13, 2022 at 2:18
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    Air cooling when drilling through steel with heavy pressure and medium speed sounds like a recipe for dulled bits and no holes. Some sort of fluid (oil or water), applied regularly, to cool the bit and lubricate the hole, plus slow speed is what I was taught and is on the inside cover of my Delta drill press. Puts the whole chart in question.
    – FreeMan
    Jul 11, 2022 at 17:45

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If you can buy only drill bits "made in America" to usually get the best quality steel. One good tip is that when you are drilling a hole in metal, start with a smaller bit for a pilot hole since the tip of the drill wears out the fastest. For example; if I want to drill out a 1/2" hole in metal I would start with an 1/8" bit, then a 1/4" bit and then the 1/2" bit. This will save the tip of the most expensive 1/2" bit. Also use a moderate amount of pressure, lubricant, and drill speed. Any lubricant is better than none.

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    You think US-made bits have better steel than Japanese or German ones?
    – bubba
    Oct 13, 2021 at 9:46
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    Most likely better than Chinese made ones, @bubba. However, if they're Chinese made, but for a known quality brand, then they're probably OK because a known brand has a reputation to maintain.
    – FreeMan
    Jul 11, 2022 at 17:46
  • So this is more a matter of sticking to respectable brands then of sticking to US made. Gods know a lot of the European tools use better steel than most cheap US tools do. So do some of the Asian tools. And some don't, from either source. The best probably coming from brands that most folks have never heard of, but at least if you go with a brand that has gotten good reviews you should avoid the worst of the junk. In any case, drill bits are, by their nature, either disposable or in need of periodic resharpening. Most Americans choose the former.
    – keshlam
    Mar 8 at 4:26
  • I read once that in USA, the importer is allowed to say "Made in USA" if they repackage the goods. Is this still true? The Chinese and Indian manufacturers will put in "Made in xxx" as required. I go by the brand, because even when they are made in China, they are supervised and/or tested.
    – Rohit Gupta
    Jul 6 at 3:00

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