318
submitted 4 days ago by mko@slrpnk.net to c/woodworking@lemmy.ca

I hope it’s not against the rules here, just saw this woodworking related xkcd that I enjoyed and thought it might be appreciated here:)

https://xkcd.com/3138

you are viewing a single comment's thread
view the rest of the comments
[-] Zwiebel@feddit.org 50 points 4 days ago

Wait 2×4s are not 2×4?? What is wrong with americans??

[-] Eq0@literature.cafe 39 points 4 days ago

They were 2x4 before drying the wood (that’s what I heard)

[-] ironhydroxide@sh.itjust.works 50 points 4 days ago

Not only drying, but sanding and straightening.

But in reality anymore they aren't even cut to 2x4 initially.

[-] panda_abyss@lemmy.ca 61 points 4 days ago

The hardware stores seem to pre-twist the lumber for you.

[-] dohpaz42@lemmy.world 35 points 4 days ago* (last edited 4 days ago)

Nah, it’s just they buy wet wood and it twists as it dries. Also, places like Lowe’s likes to stack a lot of wood vertically, so they get that nice bow in them for all those rocking chairs people want to build.

[-] captain_aggravated@sh.itjust.works 28 points 4 days ago* (last edited 4 days ago)

It doesn't shrink by a half inch in each direction.

The board is rough sawn to 2x4, kiln dried, and then milled. That milling takes it down to 1.5x3.5 inches. Used to be, the carpenter bought rough boards and milled them himself, now they do it for you to save the weight when shipping.

Oh, also: 1 1/2 inches is 1/8th of a foot. 3/4" is 1/16th of a foot.

[-] BCsven@lemmy.ca 21 points 4 days ago* (last edited 4 days ago)

There have been a few sizing changes, old framing is 2x4, there was a phase when they were milled to 1 3/4 x 3 3/4 now down to 1 1/2 x 3 1/2...probably to get more boards from same tree.

I had an image showing these various eras somewhere...

The thing that gets me is you'll buy a 2x4 and it'll have pith and bark in the same gorram board!

[-] bluGill@fedia.io 3 points 3 days ago

Old framing was not 2x4. Some of it was, but everyone has their own size they sold as 2x4. You couldn't mix and match.

[-] BCsven@lemmy.ca 5 points 3 days ago

I used to do home renos. Pre sixties era homes in southern Ontario had actual 2x4s. They were all same dimensions, and using modern stuff meant making up this difference with plywood rips.

[-] bluGill@fedia.io 2 points 3 days ago

I've seen houses like that too. I saw other houses not far away (build in 1885) where the 2x4's matched modern dimensions. Still other houses I've seen the dimensions where something else. Anything since the standard the sizes are all the same.

This is about whatever was available where you happen to live at the time they built.

[-] BCsven@lemmy.ca 2 points 3 days ago

Most we demo'd and reno'd where sized equally and so drywall could go flush back over top, and pulling out a stud from a doorway you could reuse elsewhere to match.

There was only a few where it looked liked somebody had assembled their house from random scraps. Instead of full studs sometimes they were 3 vertical pieces nailed against 2 or 3 other pieces to make a Stud, and the dimensions were all over the map

[-] litchralee@sh.itjust.works 11 points 4 days ago

Oh, also: 1 1/2 inches is 1/8th of a foot. 3/4" is 1/16th of a foot.

It's not often that I'm surprised by some of the divisors that appear in US Customary or Imperial units, but I'm now shuddering to imagine what sort of horrific system of unit names have been built atop this fact of twos-powers fractions of a foot.

Knowing the English, they'll likely have invented a name during the medieval time for 1/8th of a foot (1.5 inches), like dozebarleycorn, since a barleycorn is already 1/3 of an inch. And then 3/4" might be a demidoze, or some such insanity. The horror, the horror.

Or they'd pull a Worcestershire and pronounce "Inch and a half" as a "chunnauff." Gotta get that unnecessary U in there somewheure.

2 weeks is a fortnight, so is 2 feet a fortinch?

[-] litchralee@sh.itjust.works 4 points 4 days ago* (last edited 4 days ago)

I'm informed the British do read the time 6:30 as "half six", a shortened form of "half past six". So "inch an a half" might become "incuax", pronounced as "in-cha" and containing the unnecessary U, and an X for that Norman/French faux lineage.

Naturally, Americans would instead pronounce it as "in-coh", which would destroy any understanding when also speaking about Incoterms.

[-] bizzle@lemmy.world 3 points 4 days ago

In Kentucky it's a "tuba-fur"

In the Carolinas it's a tew-bah-fower. It's made of yella pahn, bout ate feet lawng, they got a whole mess of em down at the Lowe's, most of em are sigogglin these days.

[-] trolololol@lemmy.world 1 points 4 days ago

I'd say 14 inches is a fortinch duh

[-] bluGill@fedia.io 8 points 3 days ago

You heard wrong. They use excuses like that, but truth is they can make the final size anything they want, for many years every different sawmill decided their own final size. You start by cutting wet wood to a size, you might or might not dry it, then you plane it down to an exact size. Some sawmills started by cutting to 2x4 and then planning different amounts off. Others cut bigger so when they planed it down they finished with 2x4. Everyone did something different and so if you bought a 2x4 you better pray that sawmill remains open for when you want to remodel and need more. Eventually enough people got sick of this and decided to make a standard, the current measurements are what was decided, it was arbitrary, but at least everyone follows the same standard so you can buy from different sawmills. Exactly 2x4 is also arbitrary.

[-] ulterno@programming.dev 1 points 3 days ago

Or they could have just decided that "arbitrary" factor to be 1.
But oh well

[-] bluGill@fedia.io 3 points 3 days ago

I wish they had, but at least there is a standard, which is far more important.

[-] ArsonButCute@lemmy.dbzer0.com 15 points 4 days ago

They are until they're planed to smooth them, at which point they are approx 1.5" x3.5"

[-] Carvex@lemmy.world 16 points 4 days ago

Anything to fuck us out of our money and quality products a little bit harder.

[-] excursion22@piefed.ca 17 points 4 days ago

The American way.

[-] KingOfTheCouch@lemmy.ca 10 points 4 days ago

Just like 50x100's are usually more like 40x90's, or something even more insane - 39x86? Like I'm sorry, but the unit of measurement is NOT the problem, it's the centuries old "traditions" and "standards" to normalize dimensional lumber that are the problem.

At any rate, one should look at the names of boards as the ratio of their dimensions and leave the inches and mm out of it and it starts to make more sense.

[-] CompostMaterial@lemmy.world 7 points 4 days ago

2x4 is the rough cut not the finished cut that is sold in the store. If you shopped at a proper lumber yard, you can usually get rough cut lumber if you want to finish it yourself.

[-] Skullgrid@lemmy.world -2 points 4 days ago

you know what, fuck that name. how about you dicks call it something better?

[-] blarghly@lemmy.world 10 points 4 days ago

The 1/4 lb burger doesnt have a 1/4 lb of cooked beef, either. Its a 1/4 lb of uncooked beef.

[-] couldhavebeenyou@lemmy.zip 6 points 4 days ago

Sure but I don´t think anyone goes "well I have this project where I need to precision-fit a bunch of made-to-measure hamburgers together"

We're talking construction boards here; these boards are going to be cut to within 1/16th and then butt jointed with two 16d nails.

With precision end trimmed studs, you're probably not going to even touch them with a cutting tool, you'll pull it off the pallet and nail it in place.

[-] bluGill@fedia.io 1 points 3 days ago

They are cut to within 1/8th inch at best, and 1/4 was more likely. I was in construction for a while and this is what we did. Wood is not suitable for higher tolerance work: humidity and temperature change dimensions significantly, if you want something more accurate you need to use metals.

[-] blarghly@lemmy.world 1 points 3 days ago

No one is precision-fitting framing studs, lol.

The sawyer wants to be paid for how much tree it took to make that board. The woodworker wants to pay for how much wood is in that board. What does the lumber yard charge?

[-] Skullgrid@lemmy.world 2 points 4 days ago

And more for walnut.

[-] litchralee@sh.itjust.works 5 points 4 days ago* (last edited 4 days ago)

Although I suspect this particular quirk of dimensional lumber stems from the British, the result is not too unexpected for modern-day America. After all, we (insanely) deal with sales tax the same way, where the advertised price is pre-tax, and consumers have to do math if they want to compute the final bill before reaching the checkstand.

So having to measure the lumber to acquire its actual dimensions is entire above-board [pun intended] for anything beyond putting together a wood-frame structure.

[-] blarghly@lemmy.world -3 points 4 days ago

According to another commenter, 2x4 is the dimension of the rough-cut lumber. Traditionally, your carpenter would buy rough-cut, then mill it down himself and allow it to dry. Eventually we figured out that shipping already-finished lumber made more sense. So they sold "finished 2x4s", ie, 2x4s as they are after the finishing process. And because the actual dimensions of the sold lumber matter more than the name of the lumber, this just remains as an artifact. It would be very annoying if suddenly every 2x4 sold in stores was actually 2"x4", since now you have to shave off a half inch of every board if you are replacing a stud. And calling a piece of lumber a "inch and a half by three and a half" would be onerous. So the dimensions stay the same, and the name stays the same. At the end of the day, it's a thing that might trip you up once when you first get started in carpentry, and then you learn and it literally doesnt matter at all from a practical perspective.

Honestly, the one I want to see seppukus over is that very, very few sheets of plywood are their advertised thickness.

this post was submitted on 30 Sep 2025
318 points (97.3% liked)

Woodworking

7873 readers
4 users here now

A handmade home for woodworkers and admirers of woodworkers. Our community icon is submitted by @1985MustangCobra@lemmy.ca whose father was inspired to start woodworking by Norm and the New Yankee Workshop.

founded 2 years ago
MODERATORS