The first time I walked into my local hardwood dealer, I thought they were speaking a foreign language.
Terms like Board Feet, 4 quarter, 8 quarter, prime, rift sawn etc were unknown to me.
When I got home, I did some research and gradually over time I got to understand the trade terms you need to speek the language and make sure youre buying what you need.
A board foot is a volumetric measurement or quantity for the wood that you're buying. Hardwood isn't dimensioned into precisely measured pieces that you pay a set price or price per linear foot for.
A board foot is a cubic foot of wood. To put it another way, a piece of wood that's 1 inch thick, 12 inches wide and 12 inches deep/long would be 1 board foot.
To work out how many board feet a particular piece of wood is. first figure out the 3 dimentions (length x width x depth) = total square inches.
As there are 144 square inches in a board foot, divide that figure by 144 and that's your board foot measurement.
Example 60" x 3" x 2" = 1920 square inches
1920 / 144 = 12.33 board feet (12bf)
If you need to know how much wood to buy for a component you plan to make. Work out how many board feet the finished piece will be and double it. By the time you've trimmed, cut, jointed, thickness planed and sanded every part and glued them together to make the final component which you'll probably still finesse a little before you're done with it, you'll have around half of the original quantity left. this varies from project to project, sometimes you'll just have enough and sometimes you'll have stock you can put aside for the next project. The point is, you'll have enough.
Plain sawn/quarter sawn/rift sawn -
This is a reference to how a log is cut. You see, hard wood acts like a sponge, If it has more moisture content, it swell's, if it has less moisture content it contracts. If you want to understand how wood moves, imagine a tree trunk swelling as though someone was inflating it. That means that plain sawn wood will cup and bow as it moves whereas quarter sawn wood is much more stable.
In some species, like Oak for example, Quarter sawn will also show medullary ray flakes in the figure of the board. A popular feature in Oak furniture.
When you buy hardwood from a dealer, you're paying for nominal amounts, that is the size of the wood before any cleaning up needed to make it ready for sale to you. Yup that means you're paying for wood you aren't getting but you are actually paying for the clean up service required to make that wood marketable.
So a board has two sizes, nominal and actual. Nominal is the thickness of the board as it was when it was first sliced from the tree trunk.
Actual is the thickness of the board that you take home when you buy it.
So what's the difference and why is that important?
Well, you actually order and pay for the Nominal thickness even though you take home the Actual thickness. Don't worry, you're not being ripped off, you're actually paying for somebody to clean up (dress) the board for you. They are only doing a job you'd have to do anyway...
It's an industry standard.
Let's say you ask for 4/4. That means you are requesting a board that was 4/4" (1") thick at the saw mill. If you measure the board you'll probably find (depending on the hardwood dealers standard) that it's about 3/16" thinner after they skip planed the saw marks off both sides for you.
Here are the common board thicknesses:
4/4 (four quarter) Nominal was 1 inch - Actal typically around 13/16 inch thick
5/4 (five quarter) Nominal was 1-1/4 inch - Actal typically around 1-1/16 inch thick
6/4 (six quarter) Nominal was 1-1/2 inch - Actal typically around 1-5/16 inch thick
8/4 (eight quarter) Nominal was 2 inch - Actal typically around 1-13/16 inch thick
12/4 (twelve quarter) Nominal was 3 inch - Actal typically around 2-13/16 inch thick
Other terminologies you'll possibly hear.
S4S - Surfaced 4 Sides - This means that the board has been surface planed on all four sides so that you have less milling work to do yourself when you get back to your shop
SL, SL1 or SL1E - Straight Line 1 edge - This just means that they cut a straight edge on one side of the board for you to work from.
S3S - Surfaced on 3 sides - They left one edge rough and surfaced the two faces and the other edge.
Some hardwood dealers may ask for more information because they offer a more detailed service standard for example, I once asked for 20 board feet of 5 quarter black walnut s2s, sl1e and they asked me this question (s2s to what?).
They were asking me what ACTUAL thickness I'd like the board to be thicknessed to. So I may have said, s2s to 3/4" please.
Then there's the grade of the lumber.
There are a series of timber grades that let you know how clear the board is. That means how many knots and imperfections you should expect.
If you'd like to know more about the grading system here's a link to an illustrated guide to North American Lumber Grades
Essentially, there's FAS - Stands for First and Seconds which is basically the clearest, fine furniture board quality.
Then there's number 1 common - Often referred to as cabinet grade because it lends itself to the manufacture of standard cabinet components from the clear portions of the wood.
There's number 2a common - Often referred to as economy grade because there will be more imperfections yet this will be a cheaper board. That's not necessarily a bad thing if you tend to make smaller components.
When ordering your wood, normally you'd just go and hand select each board yourself - Remember it's considered bad etiquette to rifle through their stock of hardwood and not put everything back as you found it when you've selected the boards you want.
Don't be that guy!
If you're ordering by telephone before you go to collect it or have it delivered, in practice, you'll find that you can talk quite comfortably in most places. I used to let them know that I was still getting used to the lingo and they'd help me out. It's a great way to get to know the guys behind the counter.
If I go to my local hardwood supplier and I need 40 board feet of 5/4 FAS walnut and 22 board feet of 4/4 1 common White Oak, here's how I'd ask for it.
"Hi I need to order 40 board feet of five quarter s3s FAS walnut straight lined please and 22 board feet of four quarter 1 common white oak the same. Then I'd just answer any questions they have, if they ask.
I hope that helps, feel free to click the word 'comment' below to ask a question or start a conversation.