The problem with the metric system is the millimeter is the wrong size. It's too big for cabinet work, and .1 mm is too small to see, and measure with a scale. But 1/64 inch is ~15 thou of an inch, and I can do cabinet work with the unmagnified eye, and scale marked in 64ths. Really, why would anyone think that using the distance between the north and south pole of a oscillating prolate sphere, should form any sort of reference. Didn't these same "thinkers" try to make a 10 hour day. Ya, what thinkers came up with 12in/ft and 3ft/yd. But take any random distance, divide it into 10 equal parts using no measuring scales. Do it in base two, by fold it in half, or use your eye, which is good at splitting things in half. There's a reason for base2 fractions.For bigger distance measurement, the whole country was founded on miles, and land measurement is based on square miles. There's no farmer/rancher in the US that's going to change to hectors. Every abstract land description (the legal description) is in feet and inches, and references a corner of a township square mile indices. This is why we started and then abandoned the metric system.I also work in both systems in the metal shop, and use the system of the item I'm fixing. And I have both metric and SAE measurement tools, as I really don't like converting, mainly as ball bearings are metric. It's so much easier to keep a whole number in your head then a 5 digit decimal.For on subject, look at eBay, or Enco for import drill bits that are affordable. If you want stuff that can drill steel, they must be marked HSS (high speed steel). Inspect the drill bit, and verify it's stamped HSS on the shank. There are ebay vendors that put this in their title, (tap and die) and they are retreading only tooling. The other gimmic is TIN coating on drills. Again if they are not marked HSS, they will be "soft as butter". However I have a 115 piece set from Horrible Freight that is marked HSS on each bit, and they randomly meet this quality.