Question for those familiar with the Log scale

[Back40x2]

  I know I should probably know this question, but I honestly do not:-[ :-[ :-[  I had a discussion with a gent that told me a log scaled with the International rule, will saw out greater then scaled.

  I don't buy logs, and scale my production at the end of each day for totals.  Is he right about this, and if so why????? 

  Thanks in advance!!!!!

[Tom]

The log scales take into consideration the shape, diameter and length of the log as well as make an effort to include the kerf of the saw mill blade.  When generalities like this are entered into an equiation, the answer will not be accurate for every situation.  Some log scales are more accurate than others.  Some favor large logs.  Some favor smaller logs.  Most will be conservative  when compared with the actual Board Footage that a sawyer may be able to get from the log.

International is probably the most accurate when used to determine footage from a band saw mill, I've been told.

[wiam]

The International Rule is based on a 1/4" saw kerf.  This will give overrun with a bandsaw.

Will

[ARKANSAWYER]

  If you are buying logs by the International 1/4 scale then on the logs less then 18 inches you will have a good overrun.  On logs larger to 28 inches you will come out about even.  After 28 to what ever size you can saw with out splitting you should start picking up more overrun again.
  Now there is a differance between hardwood and softwood and it effects the overrun count.  Since hardwood is sawn 1/8 thicker most of the time you will loose a board after 9 cuts as compared to softwood.
  I count any board from 1 3/8 and down as 1 inch and any 1 1/2 to 2 3/8 as 2 inch.  So what I saw out of the log will differ with the tally of logs to lumber sold.  Scale what you saw out and do not worry about scales unless you are buying logs.
ARKANSAWYER

[maple flats]

Arkey, sure hope that variation you mention is just for figerin and not how much wander you get when sawing 8) 8) 8)

[Ron Wenrich]

I'd say it depends.  There are a lot of variables that have to be considered.

One thing is cutting patterns.  Are you sawing boards all the way through or are you cutting big chunks of blocking.  For example, a RR tie will yield 44 bf, but cut it down into boards and you'll only get 28-30 bf.

As noted, softwoods vs hardwoods.  Cut a piece a plump 1 1/2" and in softwoods it is counted as 2".  For hardwoods, its a piece of 6/4.  The softwoods will yield 25% more for the same piece of wood.

Another factor is the thickness of the boards you're sawing.  Saw all 4/4 and you won't end up with as much if you sawed heavier stock.

International scale will give a good ballpark for how much is in a log for hardwoods. 

[Dan_Shade]

I think I got the formulas correct, I have an excel sheet if someone is interested, due to how the formulas work, sometimes people will calculate slightly different numbers, but this gives you an idea of comparison of the differnt scale

Diameter is inside bark, small end, in inches, Length is in feet            
Diameter (in)   Length (ft.)   Doyle   Scribner   International
8   8   8   15   17
9   8   13   21   22
10   8   18   28   29
11   8   25   35   36
12   8   32   43   44
13   8   41   52   53
14   8   50   61   63
15   8   61   72   73
16   8   72   83   84
17   8   85   95   96
18   8   98   108   109
19   8   113   122   123
20   8   128   136   137
21   8   145   151   152
22   8   162   167   169
23   8   181   184   185
24   8   200   202   203
25   8   221   220   221
26   8   242   239   241
27   8   265   259   261
28   8   288   280   281
29   8   313   301   303
30   8   338   324   325
31   8   365   347   349
32   8   392   370   373
33   8   421   395   397
34   8   450   421   423
35   8   481   447   449
36   8   512   474   477
37   8   545   502   505
38   8   578   530   533
39   8   613   560   563
40   8   648   590   593
41   8   685   621   624

[Ron Wenrich]

Or you can use our calculators.  Hit Forum Extras at the top right on the toolbar.  You'll come up with a log volume calculator.  We even have one to scale a whack of logs.