OG help us if somebody started selling a piece of lumber that measured 2" X 4"
Can you imagine trying to do a remodel project (what most homeowner’s do) using lumber that is 1/2" wider, and a 1/2" thicker than what is already in his house?
Say you are going to remove a very large window, and put in a smaller one. (I just did this project)
The new lumber would either have to be ripped to the size of the lumber in the building, or the sheetrock around the framing would look like shit and not lay flat.
2X4 don’t measure 2" X 4" haven’t for maybe 50 years. Deal with it.
It gets worse? Where would you buy friction fit insulation that would fit? Door frames, window bucks, etc. etc.
If you want maddening, go to some rough lumber sellers, they will calculate a board that measures 4’9" x 8 1/4" (3.26 board feet) as being 5’ by 9" (3.75 board feet) even if one edge is bad. Which, for walnut in my area, can be a $7.00 difference just for that one board! But they tell you up front because they are not selling dimensional lumber.
Rick, here is New England we have the same problem - but in reverse. Many of the homes here are framed with 2 x 4’s that actually measure 2 x 4. So when you try and fix something you either need to shim with 1/2 inch plywood strips or rip down a 2 x 6. Always interesting.
And 16 inch spacing is only found in houses less than 75 years old (you know, New Construction). Before that it was whatever the carpenter felt like.
But I’m not talking about 2 x 4s, as my post made clear. I’m talking about an entire range of products – dimensional lumber, framing lumber, cinderblocks, and God knows what-all else. Some of it conforms to the nominal measurements, some of it doesn’t. Sure, if you’re careful, you’ll bring a tape measure and measure every single blessed thing you intend to buy. But gee, wouldn’t it be great if things were actually called by what they were? This business of nominal sizes is basically bogus. Just because 50 years ago there was a rationale based on the difference between rough and planed dimensions doesn’t mean we should keep using a system that calls stuff by what it isn’t, and hope no one gets confused.
(And the phenomenon mentioned by Fir na tineis basically the problem I’m usually confronting, not the reverse – though I realize those of us with old houses are a minority.)
Let me ask you again specifically what problems are cause for you by this (apparently) chaotic measuring system. I ask because nobody else in the building trades (me, for example) has this problem. I am sure that I, as well as others who have posted to this thread, can help you with some workarounds for your projects.
Look, let me give you (and any others who may be interested) a little quiz. For which of the following are the nominal dimensions the same as the actual dimensions:
Clapboards
Stair treads
Insulation
Sheetrock
Vinyl siding
Newel posts
MDF
Plywood
Hardboard
Cement block
Hinges
Pavers
Strair stringers
If you’re in the trades, you can probably get most of these right, but as I keep saying, it’s not only tradespeople who buy hinges, or plywood, or dimensional lumber, or concrete block. Where’s the rational reason for calling stuff by dimensions that it isn’t? This reminds me of a practice of my wife’s that drives me nuts, that of setting the clock forward by X minutes, to help us be on time.
I realize this is not the most earth-shattering problem out there, but it still is a minor (and occasionally major) aggravation that is totally unnecessary, if you ask me. Why the strenuous objection to calling stuff by its real size?
If you want a real-world example of where this causes a problem, imagine the poor schmuck who goes to build a bookcase with 3/4" plywood, and buys himself a 3/4" router bit to cut the dadoes. Sure, he’ll only make that mistake once, and maybe he should have known better in the first place, but still, the guy could burn through $100 worth of plywood to make a bookcase with sloppy joints.
When I learned about lumber sizes I was maybe 6. Back then a 2X4 was 1-5/8 X 3-5/8.
So what is easier asking for a two by four or asking for a One and five eights by three and five eights?
Get a grip, and deal with it.
Fir na tine I too have delt with this, I find it easier to shim than it is to rip an 8’ 2 X with a skillsaw.
Or better yet, just ask for a stud – saves you two syllables over “two by four.”
You have been given the reasons over and over again. You object, obviously. But the reason HD does it is that it is the industry standard, and if it did not, the professionals would not shop there. Feel free to start a campaign to convert everyone else to your way of thinking.
Anyone who is routing out dadoes to build bookselves out of plywood is probably using cabinet grade plywood. Otherwise, simple ledgers would suffice. That means is out the raw edges, countersinking the screws, and/or plugging the fastener voids, etc. That guy understands about nominal vs. actual dimensions, as well as the axiom measure twice, cut once
I notice you are no longer claiming that HD cheats, only that it perpetuates what is to you an irrational measuring system. Your time would be much better spent tackling metric vs. SAE, as well as metric vs. English measurements.
I just cannot believe that the group of people put out by the current lumber reference system is large enough to matter.
It isn’t, obviously, but that doesn’t meant the present system is the best possible system. The only justification for it is that many people are used to it – as am I.
And I’m not backing off my assertion that HD is cheating, either. For professionals and well-informed DIYers alike, a 1 x 10 is 3/4 by 9 1/4. And yet, you will find, not infrequently in my experience, that the 1 x 10 is more like 9 1/8 wide. The problem with “nominal” sizes is that they introduce a certain amount of squishiness that HD is exploiting, as it seems to me.
By the way, how did you do on the quiz?
Got it. Any system that is not the best possible system must be scrapped, even if it inconveniences virtually no one at all. You have a HUGE row to hoe, my friend.
Exploiting? To what advantage? What problems have you encountered that result from a 1 x 10 being an eighth of an inch shy? (I’ve asked you this before.) Is it a fascia board? A trim peice on a deck? A big-ass corner board? What kind of project do you have that uses construction grade lumber, but does not allow for trim molding or cauljking?
How does this “cheating” feather HD’s nest? You do understand that HD and every other home improvement center, as well as professional building suppliers, use the same vendors? Why is it that HD is the cheater?
Just fine, thanks.
I tried that at Home Depot…I was then introduced to “Rocky” at the customer service counter who was wearing a taupe leisure suit, gold chains, and aviator sunglasses.
“Got wood?”, I asked…
…and so my walk on the wild side began.
Believe it or not, I had this exact problem once – making a chase to enclose some water pipes. The face of it needed to be exactly 9 1/4. Now, I’m well enough versed to know to measure, but if I had been pressed for time and figured, “Okay, all 1 x 10s are 9 1/4,” I’d have been pissed. Sure, you can caulk, as you say, but I like to work with tolerances a little closer than 1/8".
The fact is, mistakes happen because the nominal and actual sizes differ – that’s what the OP is about, right? Ditto with my example about the the guy building a bookshelf. Your answer to that is basically, “Well, he should have known better.”
As to the quiz, can you give me the answers? Because I’ll frankly admit that I don’t know for many of those.
I didn’t know that, and I am an adult. I just don’t work with wood much.
Someone called? 
It’s obvious, dammit. Home Depot takes all those eighth-inches that they shave off the wood and MAKE NEW LUMBER -* for free!!!* - that they sell to unsuspecting n00bs.
It’s scandalous.
UD, I know you’re just being funny, but you’re kind of missing the point all the same. It’s not that HD is shaving that 1/8 of an inch off to supply their clandestine toothpick factory, it’s that they’re selling substandard goods, for the same price as non-substandard goods. If I’m buying a plank on the supposition that’s it’s 9 1/4, that’s what I want – just as when I buy a gallon of gasoline, I want the whole gallon, not .973 of a gallon.
Thats funny. You never complained before about getting 80% of a gallon of gas. The US gallon is a rip off !
Are the metric equivalents of 2X4’s actually 50 X 100 mm, or do they run 38 X 89?
Actually, there’s a serious question there – I believe in Europe, lumber is denominated in millimeters, and that there’s none of this game of difference between nominal and actual sizes. Can anyone confirm?