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Using log scale

Started by brendonv, May 19, 2013, 05:49:49 PM

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brendonv

I am an arborist, not a logger, so bear with me.  I have people approach me asking about buying certain logs I have, and how much board feet is in them.  How do you use a log scale?  What are the markings on them?  The test I just took for my supervisory forest products harvester license says use international scale.  So base off that.
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beenthere

Measure the small end average diameter inside the bark and the length in feet. Either use a scale stick or look up the board footage in a table.

For a more accurate scale of a log, then deduct portions of any log that has rot, or that has sweep such that the gross estimate of board footage can't be obtained.

That is the short answer. :)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

terrifictimbersllc

The log scale stick has actual ruler on both sides, usually 36" long, with inches across the top. You measure log diameter with it, and then look across from the length of that log at the scale, which is the number of board feet in the log.   The "scales" on it usually are for 8, 10 and 12 foot logs on one side and 14, 16, 18 on the other.   So for a 10 foot log 30" in diameter,  you look down from 30" and across from the 10 to see the board foot content.  As said above one usually measures the narrow end of the log, inside the bark.  If the log is not round for example oval, one takes both measurements and approximates with an average of the two scale numbers (if it says 300 one way and 320 another, then call it 310).

Or you can just put your average diameter and length into an online calculator like this one: 

http://forestry.about.com/gi/dynamic/offsite.htm?zi=1/XJ&sdn=forestry&cdn=education&tm=17&f=10&tt=2&bt=1&bts=1&zu=http%3A//www.timberbuyer.net/sawlogbf.htm
DJ Hoover, Terrific Timbers LLC,  Mystic CT Woodmizer Million Board Foot Club member. 2019 LT70 Super Wide 55 Yanmar,  LogRite fetching arch, WM BMS250 sharpener/BMT250 setter.  2001 F350 7.3L PSD 6 spd manual ZF 4x4 Crew Cab Long Bed

brendonv

Ahh I see.  So the lengths are per determined.  So for nine foot your best bet would be to average the two.  Interesting, thanks!
"Trees live a secret life only revealed to those that climb them"

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Ed_K

Your 9' log would be scaled as a 8' and if you are selling to a mill they will require 4" or 6" trim,so they can cut some off the ends for the checking that will happen.So you cut them 8'6",10'6" ect.Most mills buy in even numbers,but a few hardwood mills will buy odd footage if it's veneer.Then they'll want 9'6" or 9'10".
Ed K

mad murdock

Baileys sells  the scribner scaling and grading book, which is used here in the PNW. Spencer makes a log scaling tape which is handy for estimates. You can purchase those through Bailey's as well. I have both. You might look up the local scaling bureau for your region or talk to a log buyer from a mill in your area, back east they use international or Doyle. The mills I used to sell to in the upper Midwest used scribner back in the day.
Turbosawmill M6 (now M8) Warrior Ultra liteweight, Granberg Alaskan III, lots of saws-gas powered and human powered :D

Dave Shepard

One important thing is to make sure both you and the buyer agree on a scale before you strike a deal. Some scales favor larger logs, and some you make out better on the smaller diameters. International 1/4" is the most common scale around here, but some bigger outfits buying around here come from out in New York aways, and they might want to use Doyle. I suspect Int. 1/4" is prevalent in your area as well. I bought one of the nice aluminum sticks from LogRite.

Softwood I always buck to even feet, with 6" of trim. Cherry, I cut to any foot plus 6" trim. It's too valuable to leave a foot in the woods, especially the way it doesn't like to grow straight around here.
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Jeff

Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

terrifictimbersllc

Quote from: brendonv on May 19, 2013, 08:04:29 PM
Ahh I see.  So the lengths are per determined.  So for nine foot your best bet would be to average the two.  Interesting, thanks!

Yes on averaging between 8 and 10', or instead you can look at the 18' number and divide by two.  Not talking about what the rules are just about the closest volume estimate.
DJ Hoover, Terrific Timbers LLC,  Mystic CT Woodmizer Million Board Foot Club member. 2019 LT70 Super Wide 55 Yanmar,  LogRite fetching arch, WM BMS250 sharpener/BMT250 setter.  2001 F350 7.3L PSD 6 spd manual ZF 4x4 Crew Cab Long Bed

bill m

Quote from: terrifictimbersllc on May 20, 2013, 10:23:48 AM

Yes on averaging between 8 and 10', or instead you can look at the 18' number and divide by two.  Not talking about what the rules are just about the closest volume estimate.
[/quote]
It really doesn't work that way. The log scales take into account for a given amount of taper in a log. Using the example of an 18 ft. log the first 10 ft. may only have 1 inch of taper but the second 8 ft. log could have 2 or 3 inches of taper. So if took the bf. for an 18 ft. log and divided by 2 someone will be cheated.
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Jeff

Quote from: bill m on May 20, 2013, 08:19:22 PM
It really doesn't work that way. The log scales take into account for a given amount of taper in a log. Using the example of an 18 ft. log the first 10 ft. may only have 1 inch of taper but the second 8 ft. log could have 2 or 3 inches of taper. So if took the bf. for an 18 ft. log and divided by 2 someone will be cheated.

Exactly.
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

SwampDonkey

terriffictimbers, if you think about what your suggesting and how scale works it will come to you. ;)
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brendonv

Anyone know of an app, say for an iPad?
"Trees live a secret life only revealed to those that climb them"

www.VorioTree.com

https://www.facebook.com/pages/Vorio-Tree-Experts-LLC/598083593556636

mad murdock

If you want to be on the same page as the mill or mills in your area as far as scale is concerned, contact the scaling bureau or state forester in your area, get the scaling book that they use. The scaling books have tables for log lengths and diameters and may even be species specific as to some of the tables. The best 30 bucks I spent was getting the scaling book I did from Baileys, it is the same book that the scalers in this region use if you sell raw logs to a mill, no guess work involved. The handy dandy "tool" in the forum toolbox gets you a good estimate, but the tables in the scaling book are dead "nuts" to the "T".
Turbosawmill M6 (now M8) Warrior Ultra liteweight, Granberg Alaskan III, lots of saws-gas powered and human powered :D

bill m

mad murdock, are you saying that the mills in your area use something other then Scribner, Doyle, or International? I checked the forum calculator against my stick ( international ) and it was spot on. Most of the mills in the north east use International.
NH tc55da Metavic 4x4 trailer Stihl and Husky saws

beenthere

About all the scaling handbook could add (and I don't mean to negate it) is to show how cull is calculated to subtract from gross scale and come up with net scale for a log. Gross scale should be shown for diameter small end inside bark and log length, as found in the tool box.
Unless I'm missing something.  ;) entirely possible too.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Peter Drouin

Sweep is a big thing in logs. that will kill your scale  :)
A&P saw Mill LLC.
45' of Wood Mizer, cutting since 1987.
License NH softwood grader.

beenthere

Right Peter, and there is a deduction procedure to deduct for sweep.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Peter Drouin

A&P saw Mill LLC.
45' of Wood Mizer, cutting since 1987.
License NH softwood grader.

thenorthman

I made up a card once so I could keep it in my pocket and get a rough Idea... then realized I was calculating for a cylinder down the middle instead of a square... redid the stupid thing... one side has weight guestimations, (round log) the other is international scale for the square chunk down the middle... it doesn't account for saw kerf so its a little off vs scribner or doyle, but serve me well for ball parking it.  I'll see if I can get a pic of it or something
well that didn't work

thenorthman

Heres a pdf of it (the wifey made this up for me) reproduce it at your own risk...

The weight side is a multiplier for multiplying board feet by x number gives you y pounds per log... sorry its only for PNW timber green and dry.

Print em up and fold it in half fits in yer wallet... like I said though its only for dead reckoning.
well that didn't work

bill m

Quote from: thenorthman on May 27, 2013, 10:41:57 PM
I made up a card once so I could keep it in my pocket and get a rough Idea... then realized I was calculating for a cylinder down the middle instead of a square... redid the stupid thing... one side has weight guestimations, (round log) the other is international scale for the square chunk down the middle... it doesn't account for saw kerf so its a little off vs scribner or doyle, but serve me well for ball parking it.  I'll see if I can get a pic of it or something
I'm not sure I understand this log scale you created. Why did you use a square instead of a cylinder. Seems like you could be loosing a lot of side lumber on some logs. Also the International scale takes into account a 1/4 inch saw kerf so how did you take that out of your estimations?
NH tc55da Metavic 4x4 trailer Stihl and Husky saws

thenorthman

I didn't account for saw kerf at the time, not sure how to do that math accurately...

I usually just subtract 20-30% depending on the size of the tree, and whether or not using Doyle or Scribner (mostly Scribner here)  Like I said its ball park only.

Last I checked the mills out here don't pay for the side slabs, you only get paid for the square down the middle, and not all of it usually.
well that didn't work

Jeff

Quote from: brendonv on May 27, 2013, 05:29:28 PM
Anyone know of an app, say for an iPad?

The forum mobile view has several of our tool box calcs formated to work on a mobile.
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

beenthere

Why try to improve on the Scribner scale which is used in your area almost exclusively.
Much easier to work with others who would be familiar with what that scale predicts, seems to me.
Not to deny you the joy of working out your own tables ;)

As an example, on a 16" sm. end, 16' long log,  your square log table gives 171 bd. ft.
The FF tool box gives 166 bd ft
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

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