Read through this whole thread swinging back and forth between amusement and cringing. I was going a bit nuts after seeing mention of the dimensional lumber sizes in the customary system and it was only just short of the last post when we finally got near the actual reason for the absurd sizes the lumber is marked vs the size it actually is when purchase.
I dislike the metric system, but use what system needed to get the job done.
as for the " building materials , when was the last time you measured a "2x4" ? it hasnt been a 2x4 for a long time , also a sheet of 1/2" plywood is no longer 1/2" thick its sized metric in thickness only the 4x8 still applys so like it or not the metrics are sneaking up on us!
I'm not old enough , I'm 68, to remember when a 2x4 was 2" x 4" . They say it was before planeing. I don't know about that,we cut as close to 3 1/2" x 1 1/2" as we could, when I worked in a sawmill. I do remember 1 5/8" x 3 5/8" . In fact I'm able to get something of a date on a shop built shaper by it's 2x4 and angle iron stand.
These left me going a bit nuts. I may have looked into woodworking a biiiiit too much for it to be healthy...
2 x 4 boards were once rough cut 2" by 4". They were brought to finished size from there. I have measured old stock 2" boards that were finished at 1 3/4", five decades ago. Later, I saw 1 5/8", and now 1 1/2" on a good day, with green wood. None of those numbers were exact, and no two boards seem to dry to exactly the same size even if they were cut to identical sizes. What you measure is what you have. Work with it!
Thankfully Bob saved what little sanity I came here with.
Rough cut at the size it's marked in the store, but finishing work and drying shrink them down at a relatively predictable rate. However, Downwind2 is right in that the sizes have gotten smaller for the post-processed, post-dried state, but only when it's green is it the actual nominal size. Traditional Japanese length measurements, still used for some of their current construction, and definitely used for all of their temple maintenance, is almost as insane as our customary measurement system. The base unit is the Shaku. For smaller units, it's fine where you divide by ten for each smaller unit, but going the other way ... next size up is 6 shaku, after that, the next unit is 10 shaku, after that is 360, and after that is 12,960 ...
The customary system drives me nuts, but at least we're not measuring things as stones, chains, or butts for the most part. Although you can still ask someone how many furlongs to the hogshead their car gets ... although I'm not sure if that volume would be that used for claret, port, sherry, madeira, or beer, as they are all different... So uh, it could be worse, I guess...
