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Board Foot Calculation

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Forum topic by JKVWood posted 01-17-2017 04:12 PM 1896 views 0 times favorited 14 replies Add to Favorites Watch
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JKVWood

4 posts in 1786 days


01-17-2017 04:12 PM

Howdy.

I need help calculating this butcher block island. It’s going to be made with edge grain, 55” long, 54” wide, 1-1/4” thick. I know BF is LxWxH, but flipping the wood for edge grain is throwing me off. I’m just looking for an exact measurement, no need to count for waste, kerf, etc.

Thanks!


14 replies so far

View buckbuster31's profile

buckbuster31

256 posts in 1568 days


#1 posted 01-17-2017 04:18 PM

should still be the same board feet I would think

View splintergroup's profile

splintergroup

4972 posts in 2275 days


#2 posted 01-17-2017 04:37 PM

BF is measured for rough cut. That is, a board described as 2bf would be 6” wide by 4 feet long by 1” thick.

If finished (planed) on both sides the thickness would be more like 7/8” or 3/4” so you need to adjust your order for that difference if it applies. If the board has straight cut sides, this makes the 6” wide rough board often as little as 5-1/2”

Butcher blocks have a lot of waste with the cuts and final flattening, getting close to 2x the actual wood volume in the final product.

View AlaskaGuy's profile

AlaskaGuy

6480 posts in 3362 days


#3 posted 01-17-2017 05:35 PM

You keep saying “edge” grain. Do you mean “end” grain?

-- Alaskan's for Global warming!

View bondogaposis's profile

bondogaposis

5976 posts in 3404 days


#4 posted 01-17-2017 05:58 PM

25.8 bf.

-- Bondo Gaposis

View RogerM's profile

RogerM

807 posts in 3452 days


#5 posted 01-17-2017 07:49 PM

Board feet is a measurement of volume. I BF always equals 144 cubic inches. Therefore, Width (inches) X Length (incles) X thickness (inches) divided by 144 will give you board feet.

-- Roger M, Aiken, SC

View ScottM's profile

ScottM

756 posts in 3199 days


#6 posted 01-17-2017 08:46 PM

Try this site.

View William Shelley's profile

William Shelley

609 posts in 2522 days


#7 posted 01-17-2017 10:02 PM

An end-grain butcher block will probably have a LOT of waste. I’d factor in +20% to +40% to the actual volume.

-- Woodworking from an engineer's perspective

View MT_Stringer's profile

MT_Stringer

3183 posts in 4284 days


#8 posted 01-17-2017 10:10 PM



Howdy.

I need help calculating this butcher block island. It s going to be made with edge grain, 55” long, 54” wide, 1-1/4” thick. I know BF is LxWxH, but flipping the wood for edge grain is throwing me off. I m just looking for an exact measurement, no need to count for waste, kerf, etc.

Thanks!

- JKVWood

Got clamps? :-)

That is going to be a heck of a glue up. Good luck.
Assuming no loss for waste – 25.8bd ft. But there will be waste…quiet a bit for sure.

-- Handcrafted by Mike Henderson - Channelview, Texas

View JBrow's profile

JBrow

1368 posts in 1973 days


#9 posted 01-18-2017 12:47 PM

JKVWood,

Board feet can be calculated by first defining a surface (that has width and length) whose area in square feet is calculated. The area of the surface is then multiplied by the thickness, in inches. Re-orienting the boards effect the surface for which the area is calculated as well as the thickness measurement. The calculated result should be the same no matter how the volume of wood is defined.

If length is 55 inches = 4.6 feet and width is 54 inches = 4.5 feet, the surface area is 4.6 feet X 4.5 feet = 20.7 square feet and board Feet is 20.7 square feet x 1.25 inches = 25.9 board feet

On the other hand if length is 55 inches = 4.6 feet and width is 1-1/4 inches = .1 feet, the surface area is 4.6 feet X .1 feet = .48 square feet and board feet is .48 square feet X 54 inches = 25.9 board feet.

View ScottM's profile

ScottM

756 posts in 3199 days


#10 posted 01-18-2017 12:51 PM



JKVWood,

Board feet can be calculated by first defining a surface (that has width and length) whose area in square feet is calculated. The area of the surface is then multiplied by the thickness, in inches. Re-orienting the boards effect the surface for which the area is calculated as well as the thickness measurement. The calculated result should be the same no matter how the volume of wood is defined.

If length is 55 inches = 4.6 feet and width is 54 inches = 4.5 feet, the surface area is 4.6 feet X 4.5 feet = 20.7 square feet and board Feet is 20.7 square feet x 1.25 inches = 25.9 board feet

On the other hand if length is 55 inches = 4.6 feet and width is 1-1/4 inches = .1 feet, the surface area is 4.6 feet X .1 feet = .48 square feet and board feet is .48 square feet X 54 inches = 25.9 board feet.

- JBrow

Exactly what this site says it is….

View Robert's profile

Robert

4520 posts in 2533 days


#11 posted 01-18-2017 03:49 PM

Board feet is a volume measurement to it doesn’t matter.

The number Bondo gave is correct.

Best to always go 10-20% over to allow for imperfections in wood and the “oops” factor.

-- Everything is a prototype thats why its one of a kind!!

View RandyinFlorida's profile

RandyinFlorida

257 posts in 3120 days


#12 posted 01-19-2017 03:26 PM

For what it’s worth my downloaded APP says 24.7 BF. Several different apps available at the APP store.

-- Randy in Crestview Florida, Wood Rocks!

View GR8HUNTER's profile

GR8HUNTER

8337 posts in 1765 days


#13 posted 01-19-2017 04:35 PM



Try this site.

- ScottM

DITTO ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

-- Tony---- Reinholds,Pa.------ REMEMBER TO ALWAYS HAVE FUN :<))

View JayT's profile

JayT

6419 posts in 3264 days


#14 posted 01-19-2017 04:48 PM

There’s a different issue here that splintergroup touched on, but I don’t see where it’s been factored into any of the calculations. While board feed is a volume calculation and should not change, the reality is that it’s not a true measurement, because nominal 4/4 stock is only ~3/4in thick once planed, but calculated as if it is 1in thick.

So what I see is that while the shape that is being built is 24.8 bd ft in volume, turning the pieces on edge means that it would take 72 sticks that are 3/4in thick to get the 54in desired width. Running the calculation with that many pieces means that 34.375 bd feet of 4/4 stock will be needed to complete the project, plus waste.

If the final thickness of the planed nominal 4/4 stock is 7/8in, then it would take 29.6 bd ft of stock, plus waste.

I think that is what the OP was referring to when he said the edge grain aspect was throwing him off.

-- https://www.jtplaneworks.com - In theory, there is no difference between theory and practice. In practice, there is.

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