Board Foot Uselessness

[todd]

Too bad you didn't bother to demonstrate it. I'm looking at a price list for Cherry right now. There's a price for 3/4, 4/4, 5/4, 6/4, 8/4, 12/4, and 16/4. Guess what all those measurements are? They're thickness. That means the price varies by thickness. On my price list, it's the only thing that price varies by. Looks like it's the only variable to me.

Can't argue with that logic. By the same token, I guess square feet is essence cubic feet. Interesting that you decided not to comment on one of my points. Do you want a price list with a matrix of thicknesses and widths?

todd

[BUB 209]

The whole system would make such sweet music if they didn't keep pinch- ing off the width of boards; as in the old fascia you're trying to match up with new lumber that's nominally the same but actually a quarter inch narrower, etc.

[Doug Miller]

Maybe if you're making veneer. Not if you're making lumber.

Draw a circle to represent the cross-section of a log. Say it's 24" in diameter. For the sake of simplicity, let's assume that the bark is removed, the log is a perfectly smooth and straight cylinder ten feet long, and the saw removes a 1/8" kerf.

Now cut it into 16/4 boards. If my math is right, this log will yield one board 23-5/8 wide, two boards 20-3/4, and two boards 13-1/4 (to the nearest eighth inch). That's 305 board feet, roughly. About 76 square feet at 3-7/8" thick makes 24.5 cubic feet.

Cut the same log into 8/4 boards. It yields one board 23-7/8 wide, two boards

23-1/4, two 21-3/4, two 19-1/2, two 15-7/8, and two 9-1/2 (again, to the nearest eighth inch). That's 340 board feet. About 170 square feet at 1-7/8" thick makes 26.5 cubic feet.

Cut it into 4/4 boards. Yield is one board just under 24 wide, two boards

23-3/4, two 23-1/2, two 23, two 22-1/4, two 21-1/4, two 20-1/8, two 18-3/4, two 17, two 14-5/8, two 11-5/8, and two 6-7/8. That's 358 board feet, at 7/8" thick, or 26.1 cubic feet.

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

[Edwin Pawlowski]

You mean the price (per board foot) of 3/4 is different from 4/4 that is different from 5/4? That is not logical as most price by the bd. ft. and only vary for say, 12/4 and up, if at all. Ed

[Andy Dingley]

Doesn't matter. Your main thickness loss is in the boards cupping during drying, then you lose timber when you machine them flat afterwards. If you have the time and the log is big enough, then a thicker board can be dried and resawn afterwards, which means you're only losing curvature off two surfaces, not four.

-- Die Gotterspammerung - Junkmail of the Gods

[Leon]

If you choose to pay for surfaced wood, you have to pay for the waste also. If you were to buy rough cut wood, you would be charged for only the wood that you leave with.

[Upscale]

For most projects, you'd surface the wood before use. So, isn't that the same as paying for the waste anyway?

[Leon]

"Dave Balderstone" If the BF pricing is variale based on width and thickness, why does it

Because there would be a different price for every width of each board also if all was sold by the linear foot. Normally wood sold by the board foot is not uniform in width as it is normally sold with rough edges. If the wood that is sold in BF was sold by the foot, you would need a price for all widths, 2", 2-1/8", 2-1/4", 2-3/8", 2-1/2", 2-5/8", 2-3/4", 2-7/8" and so on. That is 8 different prices for 1 thickness of wood that is between 2 and 3" wide. Now multiply that times the boards that are 3", 4", 5", 6",

7", 8", 9", 10", 11", 12" and so on. There would be 96 different prices for 1 thickness of wood ranging from 2 to 13" wide. Measuring in BF is simply easier to price with 3 or 4 different prices depending on thickness.

Wood sold in linear feet is milled to specific widths and normally there are only 6 different widths sold between 2 and 12" wide for each thickness.

[Leon]

What is your point? You pay for all waste associated with the board you buy including the waste that every tool creates when used on the board. Sawing, sanding, planing, jointing, drilling, they all create waste.

[George]

Took a lot of posts to get this far, which is to say, to the right answer.

A foot is a convenient measurement, as is a meter, a cubit, or anything else. You've got to have a standard reference. All you decimal freaks can stow your arguments, we're talking two marks on a stick; how you divide or multiply after that is not germane. As the whole thing starts at the log, we find three common measurements depending on use in the USA.

1. Cords. A convenient way of figuring how much wood you have to cut to fill a cart or a railroad car, and the numbers don't get as big when your basic unit is already 128 cubic feet. Of course there's a lot of air in a cord, depending on who stacks it, and the logs themselves. Not a reliable measurement for other wood usage.

1. Pounds. If you have a lot of air in your stack, it doesn't make as much pulp, and though in the rough and ready days of abundance a general equivalence between cords and pounds was good enough, this age of reduced cutting and narrow profit margins makes the weight of the stack the basis for payment. BTW, species and moisture content of the load determine prices on equal poundage here.

2. Board feet. Back to a volumetric measure, because the real value is once again in the cartage and kiln operation. A truck or car is of fixed volume, as is a kiln, and the number of boards per cord is anything but precise. How can one chisel at this level? well, the days of unedged boards are gone, so the new subdivision is "grade" of board. Softwood is graded differently than hardwood, taking into account its primary use is presumed functional rather than aesthetic, though display grades are available. Frequency of occurrence of a length/width "cutting" is the primary criterion in hardwood.

Now to value added, which is a result of the high end and hobby market, where thicker and wider boards are sold more dearly. Industry buys in such quantities and requires such a variety of "cuts" that they can buy a relatively lower grade (skip planed for optical evaluation) and by gluing/glazing for a finish, make great use of everything but, as they used to say in the slaughterhouse - the squeal. Hobbyists and the high end custom business want wide boards and greater thicknesses, and since the cost of material is much less than the labor cost of the piece, they're willing to pay more for this super display grade lumber.

I guess this last should endear the sellers to the socially conscious members of the group, as it soaks the rich for the privilege of supporting their silverware on an 18 inch wide single board borne on 2x2" solid legs rather than four 4.5" wide boards borne on glued-up and glazed-to-hide-the-fact legs.

[Leon]

LOL.... ;~) And I never even felt the hook...

[Rumpty]

Leon,

I can't believe you got suckered into this useless argument... ;-)

[George]

Within that "circle" are also many grades of lumber. If the sawyer doesn't rotate it at the proper time, regardless of the width of the next board, or the average width, he can lose more money than the difference between a band and circular kerf.

He could also, given the market, end up with a bunch of thick stock and no place to sell it.

[Chris]

You are making this too complicated. Ignore thickness, width, length when comparing price.

You are looking at 3 different pieces of lumber. They are priced at $15, $20, $25. The $20 one is about 1/3 longer than the one priced at $15 and they are both 1" thick. The $25 board is shorter than either of the other 2 but it is 2" thick. Assuming you need 1" stock for your project, which is the better buy? To tell you would have to measure the length, width, and thickness of each board to arrive at the volume, then divide by 144 to get the b.f. OR if they were marked in price per b.f. you could just compare the price per bf.

2" and 1" stock of the same wood are two different animals. If you need 2" stock you can't buy 1" and if you need 1" and you get 2" instead you have to resaw it first before surfacing it, so why would you even bother unless it was significantly less expensive? And how could you tell if it was cheaper unless it was marked in b.f?

-Chris

[Dave Balderstone]

Sorry todd. Here you go:

Board feet is a measure of volume. Thickness (one dimension) is not the only variable as we also have to take width (a second dimension) and length (the third dimension) into account.

So the assertion that "with board feet pricing, there is one variable - thickness" is demonstrably false.

djb

[todd]

I don't know where you buy your lumber, but here in the Chicago area, there a only a few decent places to purchase hardwood lumber. I have two price lists in front of me. Owl Hardwood charges $4.67/BF for 3/4 cherry, $6.47 for 4/4, $6.74 for 5/4 and ... well you get the idea. Same for The Hardwood Connection. I don't know what's illogical about it. I think it's been pretty well discusses that documented that it's more expensive to finish thicker lumber. There may also be a supply/demand thing happening too.

todd

[todd]

The board foot price builds in the length and width for a particular thickness. You keep avoiding the question of how you are gonna make a price list. You want to have a matrix or what?

todd

[Tom Kohlman]

huh?

Of course you know that thickness plays into the board foot calculation so not sure where you're going with the linear foot suggestion.

I think they charge more per board/ft of 8" wide stock than they do 4" wide stock too. Simple economics caused solely by the fact that trees are round. Higher yield with narrow vs. wide and same for thinner vs fatter.