Among the most often-asked questions we get are about buying lumber for a project. Although it seems to be a very basic question, and knowledgeable folks like us should have a quick answer, it isn’t as simple as going to the grocery store for ingredients for a meal. When you buy hardwood lumber, you’re not buying the steak you want to have for dinner. You’re buying the part of the cow that the steak comes from.
How much lumber you need, and how you go about buying it, depends on a lot of things that can’t always be calculated or predicted. You can (and should) calculate the sizes of the finished parts for a project. For our August issue (which should start shipping to subscribers in a couple weeks) I built this Craftsman-style bookcase.
Some quick number crunching reveals that the finished parts will require a little less than 40 board feet (bf) of material. That’s good information, and if I were pouring a liquid into a mold, that amount of raw material would work. The problem with wood is that until you see the raw material, you have little idea how much to allow for waste.
For this bookcase, I used lumber-buying method number 1; I went to the lumber yard with my cutlist and drawing in hand and selected each piece. I was fortunate that wide material was available for most of the parts and that the stuff on hand was long enough that I could cut one 5′-long side and a shelf, or three shelves from each available 9′-long plank. That accounted for three planks, and the others would yield the the remaining parts.
I spent some time, and examined about 200 bf of material before purchasing 49 bf. I have just enough material left over to make a frame for my new poster that all the other editors are coveting. We shot some video of this process, and you can view it by clicking here.
For the October issue, I’m knee-deep in milling rough lumber and making parts for the workbench seen in the exploded view below.
This is made from 8/4 (2″-thick) material. The top sections and the legs are laminated to make thicker parts. Each top section will be 3″ thick, 12″ wide and a little more than 7′ long. The legs will be 3-1/2″ square. I called some mills to get prices, and found a good deal on ash. For this project, I used lumber buying-strategy number 2. I wasn’t that concerned about the appearance of the wood, I knew I needed a bunch, and I didn’t want to drive half a day to go get it and bring it home. I wanted to order “X” amount and have it delivered.
The finished parts calculate to be about 80 bf, so my experience with the bookcase tells me I need about 20 percent more than that for waste. If I had ordered 100 bf, I would have had to make a second phone call, and here’s why.
Cherry-picking (actually sapele-picking) the wood for the bookcase kept me away from the biggest factor that can’t be controlled , random lengths and widths. The guys at the mill loading the truck weren’t about to look at my cutlist and send me the most usable pieces out of what they had. They were going to pull “X” amount of the top of the stack and send it on its way. So instead of adding 20 percent to what I calculated, I added 50 percent. Then a little voice in my head said, “take the order up to 150 bf; the price is good and it won’t hurt to have some extra around the shop.”
This morning I glued up the last piece to be laminated, and was grateful that I listened to the little voice. Most of the parts I needed finish at 3″ or 3-1/2″ wide. Most of the lumber that arrived was slightly over 6″ wide , not quite wide enough to get two pieces from each board. I ended up with just enough material, even though I thought I was buying a lot more than I needed.
Buying lumber is more art than science, and you have to be willing to risk having extra material around to avoid the worst that can happen. The worst isn’t having extra material kicking around the shop. The worst thing is stopping in the middle of a project to go get one more board. I did end up with a sizable amount of extra material from the bench, but it all looks like this. This appears to be just about a lifetime supply of stock for baseball bats, billy clubs and hoe handles. But I have all the parts for the bench on hand, and I’m ready to start putting it together.