How do I figure a board foot?

[Haligan]

I understand that a board foot is a piece of wood 12"x12"x13/16". So, to figure how much wood I need for a given panel all I should have to do I figure the sq-ft of that panel, right? If that is true how much extra should I add for trueing the rough cut edge of the boards. I suppose that would depend on the general rough cut widths of the boards, but I didn't know if there was a rule of thumb. Plaese help I almost have a handle on this board foot thing...I think...

[Lou_williams]

You have it in general. A board foot is 4/4 stock 12 inches by 12 inches. 4/4 stock is a nominal 1 inch which after planning is more like 12/16 to 14/16 thick.

The general rule of thumb for an experienced woodworker is about 20% more stock than you need. That also depends on what kind of stock you are using. The 20% figure is for stock that is s4s (smooth 4 sides) and relatively clear. No major defects. As you move to rough stock with some defects you might need 40 to 50% over the final quantity. The advantage of buying more than you need is that you will not have to go back and find that there is not matching stock, and over time you build an inventory of wood that comes in handy for lots of things.

[dareese]

hi.... if you really want to figure bf there is an easy formula i teach the kids in my class.... #of pcs. (the same size) X thickness (if more than 1" less just drop the number) X w" X l" X .007 equals bf......

thats..... # X T" X W" X L" X .007.....

[rrich]

dareese ,
Interesting formula. Only off by eight tehths of a precent. A really good way to keep it all in multiplication and avoid long division.
Rich