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.
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.
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.
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.
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.
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, 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.
geez i got so busy measuring that i forgot to return here and look again, i want to thank everyone who helped me get this figured out, also think i am going to purchase a lumber smith portable bandmill..i have several hundred feet of old growth cedar tree on the property here and a friend in fla. is giving me a very large cedar tree,,about 24'' at base that came down last storm. guess i will be making a bunch of cedar boxes in about 3 months. i am going to try my hand at air drying.
This is all very interesting, it was somthing I did'nt have a clue about. great job everyone.
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