Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: Wood Grading Stamp

[Subject Prev][Subject Next][Thread Prev][Thread Next]
David,

I am not really familiar with Machine Graded Lumber rules or processes.  I
will say that to my knowledge, timbers are mostly (if not always) Visually
Graded.

I will point out that the company I work for generally does not like to
have to "officially" grade the timbers.  It is generally for cost reason.
It is quite expensive to have someone maintain grading certification and
generally does not make financial sense for the company that I do work
for.  We do have people that know the grading rules but are not certified.
As a result, we usually look to see if a requirement for a letter
certifying grade (or heaven forbid actual grade stamping) is really
required.  If it is, then we will hire a grader to come in to do the work.
The key thing to realize is that since we "fabricate" (i.e. cut the
timbers), if true grading is required then we have to have a grader at our
shop as grading at the mill means nothing.

Sounds as if your selection process at the Home Depot (or where ever) when
you select lumber for your own use is basically Visual Grading...just not
to the "formal" level (i.e. you are not counting knots in a certain
distance or determining slope of the wood grain, etc).  The Visual Grading
process is basically just a formalized method of what you are unformally
doing.

As to not know much about wood, one can always learn.  Prior to this job,
I was like you...could count the number of wood projects on one hand.  At
that point, I mainly know steel, concrete (although not many true concrete
projects - i.e. beams and columns - in my neck of the woods) and masonry.
But, one learns.

Regards,

Scott
Adrian, MI


On Thu, 8 Sep 2005, David Maynard wrote:

> Scott,
>
> Thank you for the enlightenment.
>
> " An example is that one difference between grades like No2 and Select
> Struct is the number and size of "permitted" knots in the middle 1/3 of the
> span (i.e. where the bending stresses would be greatest for flexural
> members).  Thus, if you bought a 20 ft 2x6 with a stamp for stay Select
> Struct and then cut it into 2 10ft beams, then the grade stamp that you have
> is potentially no longer valid (it might still be valid if the size and
> number of knots along the whole length meet the requirements for the middle
> 1/3 of the span for Select Struct)."
>
> This is why I always spec out #2 or better, and I try and utilize readily
> available wood species.
>
> "Another reason is that timber is generally not grade stamped is that is is
> generally left exposed for aesethic (as in the "rustic" look that was
> mentioned) and architectural reasons.  Now if you just paid a bunch of money
> to have a timber framed home with a lot of exposed timbers for aesethic
> reasons (i.e. want that "rustic" look), would you want a wonder, black ink
> grade stamp staring back at you while sitting in your "rustic"
> home in front of the fire?  Don't think so."
>
> 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"?
>
> "An example is that one difference between grades like No2 and Select Struct
> is the number and size of "permitted" knots in the middle 1/3 of the span
> (i.e. where the bending stresses would be greatest for flexural members).
> Thus, if you bought a 20 ft 2x6 with a stamp for stay Select Struct and then
> cut it into 2 10ft beams, then the grade stamp that you have is potentially
> no longer valid (it might still be valid if the size and number of knots
> along the whole length meet the requirements for the middle 1/3 of the span
> for Select Struct)."
>
> And this is why I hand pick all of my lumber at the yard, looking for both
> splits, checks, knots, twists, bowing, and any other "yuckys" I find
> undesirable.  But that's how I was taught, thus, how I roll.
>
> Again, thanks for the enlightenment, and I appreciate your, both, candid and
> intellegent responses to these issues.  It's nice to have a "professional
> perception" on issues like this.  Obviously, this is not my forte.  Of the 8
> years I've been doing this, I can count on one hand how many projects I have
> used wood on and still have fingers left over.
>
> Sincerely,
> David Maynard, PE
> Gillette, Wyoming
> --
> No virus found in this outgoing message.
> Checked by AVG Anti-Virus.
> Version: 7.0.344 / Virus Database: 267.10.19/92 - Release Date: 9/7/2005
>
>
> ******* ****** ******* ******** ******* ******* ******* ***
> *   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
> *
> *   This email was sent to you via Structural Engineers
> *   Association of Southern California (SEAOSC) server. To
> *   subscribe (no fee) or UnSubscribe, please go to:
> *
> *   http://www.seaint.org/sealist1.asp
> *
> *   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
> *   send to the list is public domain and may be re-posted
> *   without your permission. Make sure you visit our web
> *   site at: http://www.seaint.org
> ******* ****** ****** ****** ******* ****** ****** ********
>

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ********