Converting log volume scales
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When sellers and buyers want numbers in different scales, how do you come up with the calculations? July 22, 2003
Question
I have a problem on my hands. I have a seller that wants me to take logs in Doyle Scale. I have buyers that want everything laid out for them in International Scale or Scribner Scale. Can someone help with the conversion of Doyle Scale to both International and Scribner scales?
Answer
(Sawing and Drying Forum)
Buy on the Doyle rule, and sell on the Int'l 1/4". Your logs will yield more bd. ft. in the process.
From the original questioner:
I don't know what you mean by "sell on the Int'l 1/4"... is that another scale?
International scale is really called the International 1/4-inch scale. There is also the Int-1/8" scale.
As all the scales are represented by formulae, it is easy to convert one to the other.
I have never seen Scribner used except in the West and they do not use Doyle there. Please tell me where you find people using all three scales? In fact, using Int 1/4 is also not common. I will send you a conversion table, but it is dependent on diameter, so there is not a one number conversion.
Gene Wengert, forum technical advisor
I found that the
WOODWEB calculators work well for me. It takes awhile to put in all your logs and such, but you will get used to it. I too struggle with all the different ways that people use to measure logs and timber. Here we use good old cubic meters (424bft per m3).
Contact Wood-Mizer - they have a pocket slide ruler that has all three on it.
From the original questioner:
Sorry to confuse you. Here's the situation. I have a seller who is trying to sell logs to me by the Doyle scale. I have buyers overseas that are using what they call the "American MBF scale," which I assumed is the Scribner or International Scale.
The logs that I am interested in are 16", 17", 18" and 19" x 8', 9' and 10'.
I would make sure what scale they are talking about. We do a lot of export, and it's all Doyle scale. The price is relative to scale.
The Doyle scale is calculated as follows: (diameter-4)^2= board feet in a 16 foot log. To find the scale on other lengths, just divide that number by 16 and multiply the length.
If you look in the Knowledge Base here at WOODWEB (enter a keyword such as "scales" in the search box at the top of the page), you will find several good past articles.
Included in one article are volume tables for International and Scribner:
http://www.woodweb.com/knowledge_base/Log_Volume.html
Another includes the formula for all three log rules (given below). Formula (Doyle, Scribner, and International) for log volume:
http://www.woodweb.com/knowledge_base/Estimating_BF_yields.html
Gene Wengert, forum technical advisor
