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Figuring out approx Bd Ft from Logs

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Forum topic by Rob67 posted 05-13-2010 07:19 PM 1786 views 4 times favorited 18 replies Add to Favorites Watch
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Rob67

25 posts in 1749 days


05-13-2010 07:19 PM

I have the opportunity to get a bunch of logs but I need to figure out how to estimate the board feet per log so I know about what the logs are worth before I pursue them. I have access to a home saw mill but the guy is also new to the saw mill arena and he doesn’t know either eyt.


18 replies so far

View Nomad62's profile

Nomad62

726 posts in 1713 days


#1 posted 05-13-2010 07:28 PM

Check out “how to do stuff.com; there’s a couple of methods, do whichever works best for you.

-- Power tools put us ahead of the monkeys

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JAGWAH

929 posts in 1838 days


#2 posted 05-13-2010 07:29 PM

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TopamaxSurvivor

15090 posts in 2430 days


#3 posted 05-14-2010 04:11 AM

If you measure the diameter in inches at the butt and top, average them. OR Take the diameter in inches at breast height. Divide your diameter by 2 to get the radius. Multiply the radius x the radius x 3.14 = area of the circle x length in inches = volume in cubic inches divided by 144 = board feet in the tree. I’m sure there is some formula that allows for some waste, but I don’t know it. That is the basic math that will get you close.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View alaskan79's profile

alaskan79

74 posts in 2108 days


#4 posted 05-14-2010 06:07 AM

Do a google search for Doyle scale. You will find a chart that you can use to find BF in a log. You measure inside the bark on the small end and then need the length and it will show you the BF in the log and that is allowing for the saw cut.

Henry

-- alaskan79, Michigan

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TopamaxSurvivor

15090 posts in 2430 days


#5 posted 05-14-2010 07:00 AM

WOW!! That Doyle scale only gives about a third the bdft of calculating the mathamatical volume of a log.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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GFYS

711 posts in 2225 days


#6 posted 05-14-2010 07:10 AM

I use the Scribner scale

View Daren Nelson's profile

Daren Nelson

767 posts in 2660 days


#7 posted 05-14-2010 03:34 PM

Print this off and keep it with you. It’s a chart I made, doyle scale. If you have larger logs than are on the chart go to the one 1/2 the diameter and take that times 4.6 (say you are looking at a 32” log use the number for 16” x 4.6, make sense ?) The chart is close enough for what you are trying to do.

-- http://nelsonwoodworks.biz/

View Chris 's profile

Chris

1867 posts in 2746 days


#8 posted 05-14-2010 03:39 PM

Wow, that’s really useful Daren…

-- "Everything that is great and inspiring is created by the individual who labors in freedom" -- Albert Einstein

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PurpLev

8476 posts in 2403 days


#9 posted 05-14-2010 03:44 PM

very cool info from everyone – thanks for the links and tables

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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_Steve

85 posts in 1781 days


#10 posted 05-14-2010 04:10 PM

I owned a hardwood sawmill in northern Wisconsin for 20 years. The Scribner Decimal C scale is the standard today. You measure on the small end under the bark. Also you must deduct for crook, sweep, and other defects. Here is a link for reference. If scaled and sawn correctly, you should relize at least 5-8% overun.

THEORY AND PRINCIPLES OF SCALING

-- McMaker Woodworks, Where you can give directive for a pending antique.

View alaskan79's profile

alaskan79

74 posts in 2108 days


#11 posted 05-14-2010 06:00 PM

TopamaxSurvivor-You have to remember that you will have to take slabs off the log to get a cant and that is firewood. Plus the saw kerf. So you will not get out of the log what the true volume is. I have used the Doyle Scale on some of my logs I have milled and I get about 8% over what the chart says I should get.

Henry

-- alaskan79, Michigan

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TopamaxSurvivor

15090 posts in 2430 days


#12 posted 05-14-2010 06:42 PM

Henry, I thought there would be substanital waste, like maybe close to half, but not 2/3!! :-)

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View Daren Nelson's profile

Daren Nelson

767 posts in 2660 days


#13 posted 05-14-2010 07:32 PM

Henry, that is about my overrun too on the Doyle scale with my bandmill 5%-10%, depending on straightness/size etc. Around here we only use the Doyle scale.

-- http://nelsonwoodworks.biz/

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Daren Nelson

767 posts in 2660 days


#14 posted 05-14-2010 07:34 PM

TopamaxSurvivor here is the formula for Doyle:

(D-4)2 L
—————
16

(Small end diameter-4) squared then multiplied by the length of the log. Divide that number by 16.

Example 24”X8’ log:
24-4=20
20X20=400
400X8=3200
3200/16=200 bft

-- http://nelsonwoodworks.biz/

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TopamaxSurvivor

15090 posts in 2430 days


#15 posted 05-15-2010 02:21 AM

I think timber crusiers use breast height. Guess that is because they can’t get to the top.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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