I dont know why they have to lie about it. At $5/8ft board you’d think I paid for the full 1.5. Edit: I mixed up nominal with actual.
I dont know why they have to lie about it. At $5/8ft board you’d think I paid for the full 1.5. Edit: I mixed up nominal with actual.
No its not Maybe in the US? At least here, it is and has to be, very precise especially when it comes to industry quality. It is precise down to the mm!
That’s crazy, how can you make a profit if you give the customer the exact measurement? You have to saw a bit off and pad your earnings!
That’s not why there’s a nominal size vs actual size.
How does that work when wood varies due to moisture content? If they give precise mm measurements, only 20% of boards will meet those criteria.
All they are giving is the planned dimensions instead of nominal in mm form, it’s still not precise, it can’t be.
Construction lumber, especially pressure treated lumber, is sold so wet I don’t think it really matters. I’ve actually never tried to calculate wood movement for construction lumber because who the fuck cares? But for furniture lumber which is dried to between 6 and 14% moisture, there is a formula:
width of the board in inches x percentage of moisture change * expansion coefficient for a particular species.
Yellow pine (extremely common construction lumber) has an expansion coefficient of .00263. A 2x4 (actual dimension 1.5" by 3.5") that undergoes a 4% moisture content change will grow/shrink 3.54.00263 = 0.03682 inches, or just over 1/32". That’s in width; it’ll vary by less than half that in thickness. Wood basically doesn’t move along the grain; the board won’t get appreciably longer or shorter.
Maybe they mill, store, and sell under the same moisture conditions?
Also, how big is the difference in size and moisture for the same piece of wood? I would expect that moisture is usually not higher than 90% and not lower than 10% or something like that, but don’t know how it really is
Once it leaves the mill they go to various stores and regions with different conditions. Some places store them inside, others outside.
Once I buy it at the store and take it the site, it’s now different from the store. You should acclimate all lumber for 48 hours before using it as well, this is so the wood doesn’t swell or shrink more after installing it.
A 2x10 can be anywhere from 9-1/2 to almost 8-1/2 depending on final site conditions.
A yellow pine 2x10 might move a tenth of an inch, not a full inch.
These were bought at the same time and are both 2x10 installed a couple days ago. You can even see the difference in the connection in the picture.
Over 3/8 of an inch and they both still need to dry.
I think if I was you I’d go have a talk with your sawyer, talk about “man if I wanted my wood this wet I wouldn’t have broken up with Meagan. Is your kiln in working order?”
9-3/8 is spec, the hell you talking about?
You are just off on the amount that the wood can shrink from being rough sawn at 2” to final delivery. If one board came from a mill on a humid area, it would shrink less before milling meaning it will shrink more onsite, if the board comes from an arid region, it’s already shrunk lots before being milled. So won’t continue to shrink more.
This is the reason why you can’t predict the milled measurements and they use nominal sizes…. Not to mention the group is SPF, so it can be multiple species that shrink differently.
The difference between just basic book knowledge and actually using the material for a living mate.
Also, the hell is a sawyer? Wood comes from mills.
Okay, are we talking about “boards sold as 2x10s might vary in width from board to board?” Because I took you to mean that a given dried and milled 2x10 might move up to an inch, which it had better fucking not. Because yeah, the likes of Georgia Pacific are going to be a bit sloppy with the final dimensions of 2x10s, because it rarely matters that much for what that board is going to be used for.
I’m a woodworker, I buy rough sawn lumber dried over a period of months, I shop dry it for a couple weeks then mill it myself. I can predict with a fair degree of accuracy how much it will move.
A sawyer is an occupational term for a person who operates a sawmill. My sawyer’s name is Bill.
So, more than 10% difference, that’s enough to be a problem, indeed
Yeah but they measure in feet and cheesburgers.
And lies, don’t forget the lies
In bullshit, which is itself an imprecise metric.
Alternative facts, thank you very much
Bullshit. Wood expands and contracts so ther is no way you can be precious down to the mm.
I’ve not really encountered this wood expanding and contracting thing. Are you sure?
Absolutely sure. It’s not really a factor in construction because of how the structure is engineered, but woodworkers have to constantly think about it.
Wood expands and contracts across the grain, but not so much along it. If you take a board that has been in a dry environment, put it in a humid environment, and allow it to acclimate, it will increase in width and thickness but not in length. At the microscopic level, wood is kind of like a bunch of ropes glued together with sponge, as it soaks up water the sponge wants to expand but the ropes don’t let it expand along their length.
Us woodworkers have to think about that when building things like doors, which might fit fine in the winter and then stick in the summer. It’s why we build frame and panel doors like this:
The large panel in the middle can expand and contract so much that it might be a problem, so we literally put it in a box. The outer dimensions of the frame are made mostly of the length of boards so it won’t expand and contract much, and the panel rests in a groove in the frame, not nailed or glued in place so that it can safely expand and contract as it wants to.
Attaching wide boards end-to-face can even present a situation where the boards want to move in different directions and they’ll eventually break each other.
You can even calculate the amount of wood movement given the species, of the wood, the dimension of the board and the amount of moisture change, you can read about it here.
You aren’t serious are you…?
Exaggeration
Realistic answer
Boards can shrink and grow due to moisture.
True, but the amount they shrink and grow across the grain tends to be proportional. A 2x4 is very rarely measurably different from 1.5"x3.5", but a 2x10 (like you’ve shown) is 1.5"x9 1/4" but is often anywhere between 9 1/8" to 9 3/8"
That’s why the standards specify the moisture content of the wood as well as the dimensions. This is even the case for US standards.