Hi, I think in metric units, so almost everything is some form of a power of 10, like a kilogram is a 1000 grams, etc.
Sometimes I will think of an hour and half as 150 minutes before remembering that it is 90 minutes.
Does something similar happen to imperial units users? Because as far as I understand you don’t have obvious patterns that would cause you to make these mistakes, right?
I have a rather wide technical background and ended up pretty comfortable in both systems. I do have to do conversions in my head from km/h to mph because I’ve rarely used km/h (I’ve spent more of my time reading vehicle speed in knots).
Speaking of which, American aviation gives altitude in feet, runway lengths in feet, distance to travel in nautical miles, aircraft speed in knots, wind speeds in knots, visibility in statute miles, and temperature and dewpoint in Celsius. One of my favorite mixed unit expressions is the standard adiabatic lapse rate given as 2°C per 1000 feet.
When you’re as concerned about freezing and icing conditions as pilots are, Celsius makes sense. I prefer Fahrenheit for “what the ambient air feels like.” The scale from 0 to 100 degrees lines up pretty well with the range of temperatures found in most places people live, better than Celsius does anyway.
I learned chemistry and physics in metric. I can make technical drawings in either system, I have an intuitive grasp on what liters, meters and grams are as much as I have an intuitive grasp on what quarts, yards and ounces are.
I do carpentry and woodworking in inches though, mostly because the stock, tools and supplies available to me are designed in inches. On the peg at Lowe’s or Home Depot you might find a measuring tape with both units, most will just be inches. I do own a purely metric tape measure. So I can cut you a board 50cm long if you really want me to. It’s going to be a bigger pain in the ass to mill that stock to 20mm thick on my thickness planer, but trivial to mill to 3/4". My dado set is in fractional inches. I’ve never seen a metric router bit in person, and I’ve never seen a router collet that wasn’t 1/4" or 1/2". No I really can’t put a 6mm roundover on a board, you’re getting a quarter inch. Metric drill bits aren’t difficult to find but they’re usually for metal, so I can pretty much drill an 8mm hole in a board (split-point metal bits tend to drill holes that are a little out of round in wood). Metric brad-point bits are a little bit more specialty items, and for forstner bits, 35mm fortsner bits are specifically easy to find for installing cup hinges, otherwise they’re usually in inches.
If you were to put me in a wood shop full of metric tools and stock, it might take me awhile to get used to conventions. I’m used to thinking in terms of stock that’s 3/4" or 1 1/2" thick, for example. I’m used to talking to a sawyer in standard; what’s the metric equivalent of ordering “four-quarter” boards?
We have a lot of standard sizes that seem to be based on imperial - 12mm (1/2inch), 16mm (5/8inch), 19mm (3/4inch), 32mm (5/4inch) etc.
If you’re actually interested in taking a look, here’s a link to the dressed timber section of Australia’s hardware capital - Bunnings.
I think you just made my point for me. Are those finished milled boards or rough sawn?
In America we refer to rough sawn and finished boards differently; a rough milled board 1 inch thick and 4 inches wide is 4:4x4 “four-quarter by four”. This board will be milled to 3/4" by 3 1/2" and called a 1x4 or a “one-by-four.” If I tell a sawyer “I’m looking for some six-quarter oak” he knows I’m looking for thicker than usual rough cut stock. “I’m looking for some two-by-sixes” implies I’m looking for pre-milled construction lumber. I can say a lot about the wood I want and the condition I want it in with not many words…to an American sawyer, anyway.
Oh, and then there’s board feet! Pre-milled boards bought from retailers like Home Depot or Lowe’s are sold price-per-each because retail, but you go to a lumber yard or sawmill you’re going to pay by volume in units of “board feet.” A board foot is a 12 inch wide, 12 inch long and 1 inch thick board, or 144 cubic inches. Which sounds like a bigger pain in the ass than it is.
That’s ‘dressed all round’ what I’m assuming is finished milled. I’m a very amateur diyer - I’d imagine that if you went to a timber yard here they’d probably have a good idea what you were after. Just read online that most bulk wood is bought by the cubic metre, but all dimensioned wood is by the linear metre.
Yeah, put through the jointer/planer to make the board straight, square and true. Sometimes called “surfaced 4 sides” or S4S.