I have a log 20” 8 ft long how do you figure board feet? I’ve googled a few things but not sue exactly what to do. ?x?X?

Google log scale
Doyle log scale
Scribner log scale

Look down the table for 8 feet,
20” scaling diameter

1 board foot equals the amount of wood in 1 inch by 12 inches by 12 inches.
Therefore a true 1"x12"x12" is one board foot. A 1x12x 8' would be 8 board feet.
A 2"x6"x12" would also be one board foot. As a 2x6x8' is 8 board feet.

Is this what you are asking, or are you trying to figure board feet based on a round, tapered log? If so, I've never needed that formula so...

About 120 BF if the 20” is the diameter of the small end.

Here ya go. 128 bf


https://i0.wp.com/wunderwoods.com/wp-content/uploads/2011/10/doyle-log-scale-wunderwoods1.jpg

A board foot is 12"x12" x 1" thick. Square your log and do the math

The Doyle log scale table estimates 128 board feet in a 20”, 8’ log
Scribner estimates 140 board feet in that log.

Thanks all I’m want a walnut log cut. seeing what it might have in it. I’d like it 1 to 1.5 inches thick.

The charts and math are very helpful.

The Doyle formula is scaling diameter minus 4 squared X length divided by 16

Pie aren’t square. Pie are round.

if'n it was me, I would pick a thickness, and have it sawn in live edge slabs. Rick for 1-2 years per inch of thickness, and then edge/plane after.

I don't understand the need for charts.

If a board foot is 12x12x1 then it's 144 cubic inches of wood.

Can't you just take: Pi x the radius (in inches) squared and get the cross sectional area of the log then multiply that by the length of the log in inches and then divide by 144?

Or is there some drop calculated in those charts?

Have to calculate for waste , slabs off the edge . Log usually sawed into a cant which means it’s squared then boards are sawed off that . Rest is waste . Sometime u can get couple boards off edge . Most of waste is toward butt of log because it’s bigger diameter.

In walnut - I would also make sure to eliminate the pith in the center of the log. Either with a cut right down the center of the log once it’s been leveled to do so or by taking a slab out of the middle with the pith in it and then rip that slab to to cut the pith out. Those two narrow slabs could then be used to cut bracing/ framing etc. Leaving the pith greatly increases probability of cracking starting in the pith.

Doesn't work that way. You have to slab it off and square it up. Then you have the kerf width of each cut. Lot of waste of the round log. There are the different cuts also, rift , quarter sawn and plain that come into play . There is also the factor that some Sawyers maximize the log better than others.

Maybe BrentM will chime in , he's a hardwood log buyer/ lumber broker. Or member TWinters, he's the best Sawyer in these parts.

Getting it sawed is $1.25 a board ft is this reasonable?

$.60 a ft around here by a portable bandsaw mill. Walnut is harder to saw maybe little more for that but still cheaper than buying it

.55 to .75 is more typical

Is the $1.25 reduced if you pay a membership fee? I couldnt help myself