Log Rules

[John S]

I have never used one and was wondering which one is the best for me (if i need one at all).  Doyle, Scribner or any of the International ones.  I am portable milling with an LT40H.  Thanks!

[Jim_Rogers]

I would try and find out which one is most commonly used in your area. And use that one.

In New England it is mostly International, I believe. You could contact your county forester and ask him. He would know, most likely.

Good luck with your research.

Jim Rogers

[thecfarm]

Jim is right with the International Rule around here. I have only sold by International Rule.
What is the reason to scale logs?

[Brian_Rhoad]

Woodmizer has them in a pocket sized scale with International, Doyle and Scribner scales.

[clearcut]

Virginia Cooperative Extension has a clear and concise description and comparison of the Doyle, Scribner, and International rules.

     http://pubs.ext.vt.edu/420/420-085/420-085.html

[Ron Wenrich]

Are you looking at a way of estimating the lumber you'll saw out of a log?   Best one generally is to use International.  If you're looking at scaling logs to buy them, Doyle is the most prevalent scale in SE PA, so I imagine it would work well in NJ.

[NMFP]

A little about the log rules:
Doyle--
**Greatly under scales small logs and greatly overscales large logs.  change at approx. 26-28" diameter
**no classification on taper allowance
**assumes a 4" slab allowance with 5/16" saw kerf
**mathematical formula is algebraically incorrect and does not work[/li][/list]

Scriber--
**1" boards are drawn in circles of different diameters
**1/4" saw kerf
**its assumed that 4" is narrowest board produced
** no allowance for log taper

International 1/4"--
**Based on true mathematical formula
**Based on 1/2 taper in 4' so 16' log would have 2" taper allowance
**1/4" saw kerf
**Based on sawing 100% 4/4 lumber from each log

Here in Northeast and central PA, we use Scribner as its the most accurate depending on form class of the trees and scaling diamaters

[drobertson]

I agree with the presumption that whatever is used in the area, but an international scale will, or should suit all involved.   davdi

[NMFP]

I have generated numerous exercises for my students to grade and saw logs based on diameter, scale and deductions and consistently, Scribner has been the most consistent of the 3 major log rules.

To each their own and to the area they are in.  You just need to use the scale that you and the seller agree on and go from there.

[woodyone.john]

Log buyers down here, who are selling into international markets use J A S [japanese agricultural standard] .If you are in the business of buying logs its very good.cheers john

[SwampDonkey]

Then there again are state or provincial log rules. Here in New Brunswick we have sold to Maine on the Bangor log rule and in New Brunswick it is regulated under the Scaler's Act and NB log rule is used. So everyone is on the same page. They are both close to International, but Bangor rule scales slightly better for the seller.

[GeneWengert-WoodDoc]

I wrote an article about these log rules in Feb. 2011 SAWMILL & WOODLOT.  Check it out.  It does include formulas for the rules; most formulas are estimates...that is, the formulas came after the rules were developed.

Here is a table from that article for 16 ft logs.  (The table looks great when I click on "Preview" but when posted, it is skewed...sorry.


Log Rule                           Small End Diameter, inches
                                  6      10      14      18      22      26
- - - - - - - - - - - - - ||- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Doyle                          4      36      100      196      324      484
Int. 1/8"                     20      70      150      255      390      555
Int. 1/4"                      20      65      135      230      355      500
Scribner C                     18      54      114      213      334      500
Scribner Decimal C           2        5        11        21        33        50

For most small band mills, the International 1/8" will be right on when the log is sawn totally into lumber.  Note that Doyle and Scribner are quite close.  Both rules are trying to get a constant price per BF, rather than have a varying price with log diameter...that is, the processing cost per BF of logs for the sawmill is actually higher per BF for small logs, so the Int 1/8 rule should pay less for smaller logs as they cost more to saw per BF.

If it is assumed that the log buyer wants to pay the same amount for a log, no matter how it is scaled, it is possible to figure out the price that needs to be paid.  For example, assume that the going price for a log is $400 per BF Doyle.  Then when scaling International 1/4", which will give the correct footage for the seller and buyer and not underestimate, the log buyer must have a sliding rate pay scale to accommodate the extra handling and sawing costs for smaller logs.  The buyer should pay $80 per MBF for 6" logs; $220 for 10"; $296 for 14"; $340 for 18"; $364 for 22"; and $388 for 26".

[SquareG]

Every sawmill I use is buying my logs by doyle here, and they still prefer big logs.  And slide pay at 12", or don't take them at all.

[dboyt]

Since you're portable milling (like me), I assume that you want to be able to estimate how many board feet you'll get out of a customer's logs.  International 1/8" comes closest (assumes 1/8" kerf), but International 1/4" + 15% comes very close, if you don't have access to the 1/8" scale.  Measures for all scales base diameter on small end, inside the bark.  There are standard formulas for sweep and crook.

If you are buying or selling logs, you need to go with whatever is conventional in your area.

[NMFP]

With all of the band mills out there and operating every day, why is it almost impossible to find an international 1/8" stick for sale?  They are out there but found from very odd suppliers many times.

I have actually had my students calculate and construct an international 1/8" scale and they work great, providing you saw all lumber to 4/4 thickness.

[Jim_Rogers]

Actually this is the first time I've ever heard of a 1/8" scale.

Jim Rogers

[Peter Drouin]

Actually this is the first time I've ever heard of a 1/8" scale.

Jim Rogers

x2

[Magicman]

I have never used one and was wondering which one is the best for me (if i need one at all).  Doyle, Scribner or any of the International ones.  I am portable milling with an LT40H.  Thanks! 

Since I am portable and only saw customer's logs, I have never needed a log scale.  Occasionally we might wonder how many bf are in a particular log and measure the DIB/small end and look at the charts printed on the sawmill blade cover.  I also have a WM sliding chart that works.

My billing is either scaled lumber or hourly rate.  I neither buy logs nor sell lumber.

[landscraper]

"Actually this is the first time I've ever heard of a 1/8" scale."

International 1/8" predates 1/4" by 11 years, 1906 vs 1917, but 1/4" scale was more accepted because Clark wrote the 1/8" scale with bandsaws in mind, and of course there were lots of circle saws in operation in that eras with wider kerfs.  So, 1/4" became more prevalent as it was more applicable, and 1/8" took the back seat, or so I've read.

All the hardwood buyers I have dealt with here (Central Va.) scale Doyle, and are happy to do so, in that most of the logs around here are under the 26-28" break-over point where Doyle becomes generous rather than stingy.  I did sell paulownia logs one time to a small exporter/buyer who scaled differently, maybe International, can't remember. 

Tree length SYP goes by the ton, and cut pine sawlogs can go either ton or BF depending on who is buying.

Did you know that between the U.S. and Canada there have been over 70 different log scales in use over the last 150 years?  Many were regional scales only used in a particular area.  I had an old forestry book that told me that.  The list of scale names was as foreign to me as greek. 

[GeneWengert-WoodDoc]

An interesting 68 page booklet is "A Collection of Log Rules" which is at
http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr01.pdf

Just in case someone has missed it, the 1/4 or 1/8 in the previous discussion is the saw kerf.  So, in today's thin kerf bands, maybe we need an International 1/16  rule?

But, I do agree with the previous comments that when buying logs, the logger often has a value in mind for his logs.  When you scale them and figure a price that is too low, you should work with (i.e., talk to) the logger carefully (and raise your price) to assure that he will bring you more logs in the future and not drop them off at a different sawmill down the road--if they are good logs.  But if you are scaling for your own estimate of what you should get and then plan to compare your estimate with the actual footage you get when sawing, the International Log Rule is best.  But, after scaling, you also need to take the appropriate scaling deductions for sweep, decay, seams, etc; such deductions are given ion many texts on scaling.  If you want to beat the International scale, saw thicker than 4/4 and / or saw a large can't pout of the center.  This reduces the amount of sawdust and increases the footage.

[WoodenHead]

I use the Ontario log rule in my neck of the woods.  It scales less than International by about 10-15% depending on diameter.  Generally it seems to track my actual output from the saw very well.

For those of you who like formulas here it is:
Bdft = (0.55D*D - 1.2D) x L/12
Where D = diameter at the small end in inches
L = the length of the log in feet

There are allowances for defects, but I have yet to see a logger who applies them as they are written (particularly when it comes to sweep) .   :D  Usually the 10-15% below International covers me.

In comment to Gene, I would not suggest a 1/16 International, since most band saws typically have 1/8" kerf (maybe 3/32").

[Chuck White]

I don't scale very often, but sometimes I'll have a customer ask "how many bf in that log", so I'll have to figure it out!

I use the International ¼ inch scale and add 20% and it comes out pretty close to actual board feet sawn!

[dablack]

I really don't have anything to add except when I read the title to this thread, I read it as, "Logs Rule".  As in "LOGS RULE!"

I thought, well, this guy sure is excited about sawing!  Then I opened up the thread and realized I had read it wrong.

HA!

Austin

[Magicman]

Austin, my mind has read it the same way several times.  I have clicked on the topic several times before realizing again that it is about rules, not logs.   ;D