2x4 in the rough is 1.5 x 3.5 inch when milled square. Depending on the moisture content when milled and how it is stored/dryed there could be considerable stray from the full, nominal size.
I thought the radii was a feature because right angles are more difficult to slip into place and tend to splinter more. You're probably right that it's a cost-saving measure though.
The wood in the radii is lost to sawdust. Perhaps they sell this sawdust as a product, but it’s more likely just to make it easier to handle and less likely to get damaged or damage something else.
It’s a “coproduct”, the value of which is roughly inverse to the price of lumber and other finished manufactured end products.
It goes into things pulp and paper, pellet stove fuel, cogen plants and if useless for anything else, the “hog” in the basement of the mill.
Fun fact: any contamination of chips with plastic or metal makes the value of a load as large as a rail car worth zero, so QC are super anal about keeping it out
I don't see this as a cost saving - the radius isn't material that would make it onto another piece of lumber, it'd be the waste between rectangles. In addition, keeping a machine tuned and sharp to cut the radius costs money.
I would assume two possible reasons: the radius reduces stress concentration, and facilitating handling and packaging (think splinter fall-off debris, and likelyhood to bind up on a sharp edge)
I had intended to point out the minimal amount of this material; I'd be surprised if you could offset the cost of additional milling just to recover it
I worked in a retail lumber yard in the mid-1970s and learned to be very patient with crochety old pharts who complained that "a 2x4 used to be a full 2"x4" dagnabbit..." Am now a somewhat crochety old phart myself, and was surprised to find that 1.5" x 2.5" actual (2"x3" nominal) is considered adequate for some studs. Source: https://www.homedepot.com/p/2-in-x-3-in-x-96-in-Select-White...
Am pleased to see that effective hacking has a long history:
> Dimension was fitted into place by the carpenter, more often than not with his hatchet.
> Am now a somewhat crochety old phart myself, and was surprised to find that 1.5" x 2.5" actual (2"x3" nominal) is considered adequate for some studs.
You can frame a wall with 2x3s 16" on center as long as it's not load bearing. That seems pretty reasonable to me, since it doesn't need to do more than hold up the drywall, partition the space, and stand up to people bonking into it.
In Fire Walk With Me, there was a deleted scene, now available on The Missing Pieces, involving a confused man who believed he had been shafted out of some wood versus the lumber yard. I had never given it much thought but the scene more or less goes over the why.
> The 2x4 you purchase at the Amish sawmill is considered wet lumber and is full size but will shrink while drying. The 2x4 from an Amish sawmill will measure a true 2 inch x 4 inch measurement on a tape measure.
> Size standards, maximum moisture content, and nomenclature were agreed upon only as recently as 1964. The nominal 2x4 thus became the actual 1½ x 3½, imperceptibly, a fraction of an inch at a time. It was a 34 percent reduction in actual volume; as those in the trade would say, it’s “selling air.”
> Today, everyone in the construction industry knows that nominal size is not actual size—despite the fact that the 2x4 designation persists in the marketplace. So, why does the awareness about the “slimming” of its actual size matter? For one, we must dispel any notion that the current size is a perfect utility equation of structural performance in terms of strength-to-size ratio.
> Instead, let’s recognize that the evolution of the 2x4 resulted from economic compromise based on simplifying differences and creating a nationwide standard for customers. It is utility optimized for construction speed—speed in shooting together single-family light-stick stud homes which represent more than 90 percent of the residential housing market.
That source was so much clearer and succinct a read than the long PDF with every historical anecdote. I mean, maybe if you're a wood enthusiast you could muster up the enthusiasm to read the 60 page dissertation ...
The text quoted above is a short essay on the same topic from Harvard. Here's the Forest Service PDF summary:
> Lumber size standards came into being almost a century ago to meet the need for a common understanding between the mill and markets that were separated by increasing distances of rail or water transportation. Early concepts called for rough lumber to be of full nominal size, often in the dry condition. After World War I, the increasing demand for construction lumber led to the first national size standard in 1924. This was revised in 1926, 1928, 1939, and 1953, while still another revision is proposed for adoption in 1964.
> Demand for lumber in World War II led to the shipment and use of large quantities of lumber dressed green to standard sizes. That use has continued to the present time, while experience has accumulated on how to deal with the seasoning and shrinkage of lumber in place in a structure. The proposed new lumber standard recognizes both green and dry lumber, requiring the former to be of larger size so that both will be of the same size when they reach the same moisture content in use.
> Economic pressures among the regional areas of lumber production have resulted in a decrease of standard lumber sizes over the period covered by this history.
I used to really admire the forest service, before I learned that they are basically the harbingers of destruction for old growth forests. They have butchered far more than they protect, and primary forest is being harvested to this day with their blessing.
The mission of the USFS is to provide forest products to Americans in perpetuity. If you imagined they were a conservation agency, that was just your imagination. The only conservation mission of the USFS is to operate forests in a long-term steady state of growing and harvesting.
I believe most carpenters in the UK would still say '2 by 4' and '2 by 1'. Odd, as those values are pretty much meaningless, as they refer to the original size of the timber before it was planed down. In this sense, those dimensions have now become terms.
GlueLam is fantastic, in the right context. I've seen large church spans in it which were modernist takes on old craft, beautiful both as wood and engineering. I still like massive Oak beams, but I like GlueLam too.
Plywood is fantastic. Look at the Mosquito! But more seriously, it was a designers dream from the day they got it "right" for tensile strength and glue/moisture issues.
MDF is kind of meh. It weighs a tonne, and it sucks paint up like a builder in the bar after work. But it has it's place. Damp.. nightmare.
(had work done on a wooden house in Qld, it made extensive use of GlueLam for structural support, Plywood for rigidity and wind shear load bearing, and MDF for routed patterns: walls and ceilings in Qld used (and still often are) made of (vertically joined, in the case of walls) Tongue-and-Groove or "vee-jay" and is very hard to get at old dimensions, and lumber from a "restoration station" (recycling centre) is very exy now. So for mixing new build with old build, MDF+router == same width pattern of VJ grooves.
If its structural and hidden (or not, if you like it's look) then manufactured wood is really great stuff.
Covered wooden bridges last hundreds of years and they are very beautiful. Maintenance is required (as with everything) but life cycle cost is really good especially for shorter spans.
GlueLam hasn't existed long enough for the glue-lamination aspect to be understood for climate, the way solid timbers are. I wanted to believe composites of all kinds had better lifecycle but it turns out Nature has some tricks up its sleeve which we don't yet entirely emulate, when it comes to longevity.
Down in Tasmania there are thousands of tonnes of flooded forest woods, which are being dredged up 50 or 60 years down in the cold dark dam-water, and being turned into exquisite furniture and musical instruments. I'm told almost petrified Kauri Pine can be the same, other woods turn into something magical when left alone for a long time. Put GluLam to the same test, It's probably not happy outcome.
Agree! The wet dry cycle at some point seems almost certain it would cause delamination. I'm surprised those failed bridges aren't more protected, it does seems risky, it seems they should be kept out of direct weather. Also agree glulams dont have a 100+ year track record, but it's getting there. They solve so many other issues such as efficient utilization of low grade and sustainable wood...so count me a cautious but excited proponent.
Good story about the Kauri Pine, that looks like a pretty cool tree!
Front page of the .pdf shows a neat lumber gauge in action. It's designed to fit on your finger and allow rapid checking of common dimensions. You can still buy these...or, in this case, an excellent reproduction here: https://www.leevalley.com/en-ca/shop/tools/hand-tools/markin...
46 comments
[ 2.9 ms ] story [ 102 ms ] threadconsidering the inputs, modern lumber is a stunningly consistent and reliable product.
Except now they've found a new way to cheat by putting excessively large radii on the corners of construction grade lumber.
I would assume two possible reasons: the radius reduces stress concentration, and facilitating handling and packaging (think splinter fall-off debris, and likelyhood to bind up on a sharp edge)
Am pleased to see that effective hacking has a long history:
> Dimension was fitted into place by the carpenter, more often than not with his hatchet.
You can frame a wall with 2x3s 16" on center as long as it's not load bearing. That seems pretty reasonable to me, since it doesn't need to do more than hold up the drywall, partition the space, and stand up to people bonking into it.
> The 2x4 you purchase at the Amish sawmill is considered wet lumber and is full size but will shrink while drying. The 2x4 from an Amish sawmill will measure a true 2 inch x 4 inch measurement on a tape measure.
L. W. SMITH, Wood Technologist and
L. W. WOOD, Engineer
Forest Service, U.S. Department of Agriculture
Strangely appropriate.
> Size standards, maximum moisture content, and nomenclature were agreed upon only as recently as 1964. The nominal 2x4 thus became the actual 1½ x 3½, imperceptibly, a fraction of an inch at a time. It was a 34 percent reduction in actual volume; as those in the trade would say, it’s “selling air.”
> Today, everyone in the construction industry knows that nominal size is not actual size—despite the fact that the 2x4 designation persists in the marketplace. So, why does the awareness about the “slimming” of its actual size matter? For one, we must dispel any notion that the current size is a perfect utility equation of structural performance in terms of strength-to-size ratio.
> Instead, let’s recognize that the evolution of the 2x4 resulted from economic compromise based on simplifying differences and creating a nationwide standard for customers. It is utility optimized for construction speed—speed in shooting together single-family light-stick stud homes which represent more than 90 percent of the residential housing market.
I don't know why HN even permits the linking of pdf's if they can be a vector for arbitrary execution and privilege escalation.
> Lumber size standards came into being almost a century ago to meet the need for a common understanding between the mill and markets that were separated by increasing distances of rail or water transportation. Early concepts called for rough lumber to be of full nominal size, often in the dry condition. After World War I, the increasing demand for construction lumber led to the first national size standard in 1924. This was revised in 1926, 1928, 1939, and 1953, while still another revision is proposed for adoption in 1964.
> Demand for lumber in World War II led to the shipment and use of large quantities of lumber dressed green to standard sizes. That use has continued to the present time, while experience has accumulated on how to deal with the seasoning and shrinkage of lumber in place in a structure. The proposed new lumber standard recognizes both green and dry lumber, requiring the former to be of larger size so that both will be of the same size when they reach the same moisture content in use.
> Economic pressures among the regional areas of lumber production have resulted in a decrease of standard lumber sizes over the period covered by this history.
I have heard it, but only in the way of inferring that it was being used in an abnormal or "flat" orientation, such as for a floor truss assembly
https://www.buildingmaterials.co.uk/nuts-and-bolts/guides/4x...
Plywood is fantastic. Look at the Mosquito! But more seriously, it was a designers dream from the day they got it "right" for tensile strength and glue/moisture issues.
MDF is kind of meh. It weighs a tonne, and it sucks paint up like a builder in the bar after work. But it has it's place. Damp.. nightmare.
(had work done on a wooden house in Qld, it made extensive use of GlueLam for structural support, Plywood for rigidity and wind shear load bearing, and MDF for routed patterns: walls and ceilings in Qld used (and still often are) made of (vertically joined, in the case of walls) Tongue-and-Groove or "vee-jay" and is very hard to get at old dimensions, and lumber from a "restoration station" (recycling centre) is very exy now. So for mixing new build with old build, MDF+router == same width pattern of VJ grooves.
If its structural and hidden (or not, if you like it's look) then manufactured wood is really great stuff.
Down in Tasmania there are thousands of tonnes of flooded forest woods, which are being dredged up 50 or 60 years down in the cold dark dam-water, and being turned into exquisite furniture and musical instruments. I'm told almost petrified Kauri Pine can be the same, other woods turn into something magical when left alone for a long time. Put GluLam to the same test, It's probably not happy outcome.
Good story about the Kauri Pine, that looks like a pretty cool tree!