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RE: Wood Grading Stamp

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Buddy Showalter can probably give you a better explanation, but this is
from my understanding:

Machine Graded Lumber is a term that covers Machine Stress Rated Lumber
(MSR) and Machine Evaluated Lumber (MEL).  The NDS list design values
and appropriate factors for MSR and MEL graded lumber.

http://www.spib.org/mglumber.shtml?/lumberservices.

MSR graded lumber is typically done in a dynamic setting.  Lumber if
flexed at line speed with a set of rollers.  The force required to
deflect the piece a known displacement is related to MOE of the lumber.
The strength of wood correlates well with density and MOE, thus, the MSR
machine spits out an MSR grade.  (Sorry for this gross simplification
for MSR aficionados).

MEL lumber is also a nondestructive evaluation of the lumber.  I believe
it measures density, and perhaps some other properties, and related
these properties back to strength/stiffness (again, sorry for the gross
simplification for MEL aficionados).  Hopefully the SPIB website can
answer more of your questions.

The point of Machine Graded Lumber is trying to get a better prediction
of lumber properties than solely based on visual inspection.  The two
methods are using a machine to take some of the subjectivity out of
lumber grading.

Tom


-----Original Message-----
From: David Maynard [mailto:davemaynard(--nospam--at)ceincorp.com] 
Sent: Thursday, September 08, 2005 11:05
To: seaint(--nospam--at)seaint.org
Subject: RE: Wood Grading Stamp

This makes tons of sense, however, I was unsure as to how this type of
material would show up on site and if a contractor would actually use
"Visually Graded Lumber" as opposed to "Machine Graded Lumber" for this
type of practice.  Again, I don't mean to sound combative (which the
written text often times can come across), but rather, I am looking for
more information on the subject as well as a little bit of
enlightenment.  Also, would you care to explain the process of "Machine
Graded Lumber"?

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