View Full Version : How to calculate cubic feet of kerfed box?

kfx450r

08-28-2013, 10:54 PM

Not your typical kerfed ports. Front side of box will be one gradual kerf, will be kerfed in the middle and there will be a 10 mounted on the bottom front and top of the box with a slot port either at the top or bottom.

So imagine a square with 2 sides forming a curve connecting them instead of joining at a 90 degree angle, thats what I'm planning.

bbeljefe

09-01-2013, 02:03 PM

Figure the area of a circle that would be the same size as the rounds you're making and then deduct 25% (for each 90° kerf) of that area from the square area the box would have if it were not rounded.

For example:

1' * 1' * 1' square box = 1728 cubic inches (net volume).

Now lets kerf two corners of that box based on 4" circles.

Pi*Rē or, 3.14159 * 2 * 2 = 12.56

circle surface area * height or, 12.56 * 12 = 150.72 inⁿ ←This is the total volume of a 4" cylinder that's 12" tall.

Divide that volume by 4... 150.72 / 4 = 37.68 inⁿ for each kerfed corner.

Take your total 1728 inⁿ and subtract each rounded corner volume.... 1728 - 37.68 - 37.68 = 1652 inⁿ or, .956 ftⁿ.

R34P3R

09-01-2013, 02:09 PM

Figure the area of a circle that would be the same size as the rounds you're making and then deduct 25% (for each 90° kerf) of that area from the square area the box would have if it were not rounded.

For example:

1' * 1' * 1' square box = 1728 cubic inches (net volume).

Now lets kerf two corners of that box based on 4" circles.

Pi*Rē or, 3.14159 * 2 * 2 = 12.56

circle surface area * height or, 12.56 * 12 = 150.72 inⁿ ←This is the total volume of a 4" cylinder that's 12" tall.

Divide that volume by 4... 150.72 / 4 = 37.68 inⁿ for each kerfed corner.

Take your total 1728 inⁿ and subtract each rounded corner volume.... 1728 - 37.68 - 37.68 = 1652 inⁿ or, .956 ftⁿ.

Where on earth did you come from? I didn't think knowledgeable people joined this forum anymore. Everytime I see you post, it is actually valuable, helpful information which is very few and far between here.

bbeljefe

09-01-2013, 02:53 PM

Thanks for the kind words. But don't speak too soon... I'm liable to go on a bender at any time and live right up to your low expectations of members... :naughty: