I have a question that ought to fall into the dumb category, but I am getting "answers" to it that are inconsistent.
I have all the "US standard" drill bit sizes already. However, there used to be (at least) a "set of standard" metric drill bit sizes you could assume most machine shops had in stock. That is what I am looking to find.Why just metric? My Zeus pocket book includes imperial, letter and number sizes which will get you a better hole size match?
Ken -- None of the McMaster-Carr "sets" match what I am told by C;eve;and/Greenfield, American, or Cincinnati.Lew,
Maybe there is something you would call "Standard" here: https://www.mcmaster.com/metric-jobbers'-drill-bits
I have no leg to stand on to disagree with you. I know that whereas I can buy drill bits as large as 3.500 inches, few shops stock drill bits larger than 1.500 inches in diameter as it is simple to set up a boring bar for anything larger than (say) 1.375 inches in diameter. I would assume that a similar "judgement call" apples to the metric side of the universe, I am just unaware what that "judgement" is -- though I am willing to learn!Over time I have seen a lot of rationalisation of drill sizes and styles from manufacturers and with buy outs and acquisitions there have been significant changes to what drills are available.
Brands like Dormer and Guhring have changed significantly over the last few years.
Added to that the different machining methods and type of machines available has also had an influence on what
drills are available.
With that in mind i have not seen a drill bit or what we down here call a jobber drill over 20mm in dia from any supplier we have.
I shan't disagree about the (Factory of the Future) developments im drilling technplogy, bit sizes amaller than (say) .750 still tend towards more conventional Drill Bits.We used to have a wide range of large drills but these days we use tipped "cam" drills or "U" drills which blast through material in a fraction of the time that the old drills used to take. So basically the large drills are just not feasible any more.
It is not so much the material removal speed as it is the resulting accuracy of the hole size when using llarge diameter drill bits (as well as the cost to acquire and maintain them).Generally drilling is the lowest cost way to remove material from a hole. So large drills do make sense.
Any machinist worth their salt knows how to improve the accuracy and precision of twist drill created holes. The problem is that machinist's worth their salt are overseen by incompetent mis-managers at leat 90% of the time.Drilling is not generally famous for hole size accuracy. Nor location , roundness, or straightness either.
But drilling makes a cheap hole.