Grading Timbers

[mark davidson]

Hi Folks,
I'm currently looking at having some grading done(Ontario, Canada), and also looking at getting certified so I could do it myself. Are any of you doing your own grading? The reading I've done does not look promising, but most of the material I can find is coming out of the USA.
would be great to update myself on what other framers are doing about grading these days.
thanks,
-Mark.

[Jim_Rogers]

Grading information

All I can do to help you is tell you about several experience I've had.

My first meeting with a timber grader was when a client of mine needed his timbers graded for a barn he was constructing. He was making this barn out of recycled timbers.
He and his carpenter hired the traveling grader from the lumber manufacturer's association which covers our area. This is NELMA which stands for New England Lumber Manufacturers Association.

The grader arrived and wanted to view each timber on all four sides and both ends. So I had to use my fork lift and lay them out on the ground on blocks so that he could roll them to inspect them. He also wanted to know which timbers were labeled to be posts, and which ones would be beams or rafters.

As he inspected them, if they passed, he'd mark them by stamping the timber, on the end grain of the piece, with a grade stamp hammer.
If they failed inspection then they didn't get stamped. And the rejects were sorted out and cut up into other nonstructural pieces.

After he was done, he left and prepared a document saying that he had inspected the timbers and marked the ones that passed. I never saw the document but this was to my understanding sent to the client and shown to the building inspector of that town.

Years later, I had heard this grader speak at a TTRAG gathering and he stated at that time that his association would no longer grade stamp used timbers.

Some time after my first meeting with this grader the Sawmill and Woodlot magazine held couple of grading workshops. I attended both of them.
One was held in Maine and one in New York state.

The grader was the main speaker at the beginning of the first session. He told the group of about 60 portable sawmill sawyers that there was no way that their organization was ever going to give out grade stamp authorization to a portable sawmill. The reasons were that the organization wanted to know where the grade stamp was every day, of every week, all the time.
If a portable mill took off then they wouldn't know where the grade stamp was. The reason for this is that the lumberman's associations are self policed. The traveling grader also inspects mills and makes sure that the grades of lumber being shipped out meets the grade. And if they don't then the mill is in big trouble.

What he suggested we do is: buy a grade book and learn one grade rule at a time. Then once we have that grade rule deeply pressed into our brains, learn a second rule. And so on.

At both these grading events, only boards and 2by stock were inspected. And we were shown how to grade these. To get the samples used the graders just went down to the local big box store and bought some lumber.

I asked, after attending the second grading session, if it would be possible to have a session on grading timbers. The head grader told me that it would be difficult to do as they would need timbers to inspect.

My thoughts were that there were 60 sawyers there, and if only half of them had brought one timber each we'd have had 30 timbers to look at. Just about every sawyer there had a pickup truck and could have hauled one 8' timber in the back.

I personally would have brought 10 and I would have intentionally brought some really bad stuff to show them what is bad...... You learn from making mistakes....

A 2x4 isn't very strong with a 3" knot in it......

At the TTRAG event where I heard him say that they wouldn't inspect used timbers anymore, we traveled to a local mill and saw some timbers there. And he showed the group some of the many things you have to understand to grade timbers.

This session wasn't very long and with such a large group standing around one small pile of timbers it was hard for everyone to see and hear what he was explaining. And I came away from that thinking that it wasn't the best way to do it, and it didn't help me much at all.

I did purchase a grade rule book. And I've learned how to inspect timbers for meeting the grade 2 rule.

Most frames are required to have "grade 2 or better" timbers. If the grade 2 rule says a knot can be this size, and you're knots on your timbers are smaller than that, then your timbers are "or better"......

I try to make all my timbers for timber frames be the best they can be to be accepted by the "grade 2 rule" or better....

Since this happened, the government of New York state has adopted a new rule that says the sawyer can sign a document declaring that the timbers meet that "grade 2 rule" and that inspectors can accept this document instead of an official grade stamp.

I believe that New York is the only state that does this.....

Sorry for the long post....

[Raphael]

In CT there is no way to get large timbers 'graded', but a residence or public structure needs graded timbers and a barn does not.

  My building inspector wants old timbers being repurposed inspected by a "trusted engineer", if they aren't being repurposed then they are considered an existing house and don't need inspection.  The only limitation on new timbers is they must come from a "known sawmill".  The sawyer I dealt with did a pretty good job, and I only rejected a few timbers.

I suspect your best bet is to check with the local building official.

[mark davidson]

Thanks Jim for the information, and yes, in the past I have always asked the building inspector about the project, and so far I have not needed to have anything graded. Seems like I'm getting into more projects, and more of it is residential, so I'm updating myself on grading. I've asked the mills that I work with about this, I'll get back and let you all know what they think.

[Brad_bb]

About a year ago, I believe Jim_Rogers pointed me to the following link for learning grading rules.  This is the website for the Northeastern Lumber Manufacturer's association.  Once at the site, under the "Reference" pull down, select the Grading Rules.
http://www.nelma.org/

[swampfox]

Jim, that sounds like a frustrating experience.  I would think that the sawyers who deal with the material on a daily basis would have the best insight into what is "stamped".  Would you agree with this?  Perhaps you can share with us what you see and interpret when turning butts into timbers.  In other words, are there any indicators when looking at a tree that can give you a glimpse of the value of the timber inside (its grade).  Or can you tell its "grade" by the way it behaves when it is sawn? 

Or is there no connection in these steps to its final grade?

I realize that asking you to do this could result in the longest post ever.  Maybe a link instead?

what do you mean by "would no longer grade state used timbers."

Thanks in advance for any feedback.

[Jim_Rogers]

what do you mean by "would no longer grade state used timbers."

swampfox: sorry typo it should have said, and now does "would no longer grade "stamp" used timbers.

The reason they said this is that they have no way of knowing how much stress each timber has had applied to it and how many of the internal fibers have been damaged by these stresses, and therefore weakening the timber....

[Jim_Rogers]

I would think that the sawyers who deal with the material on a daily basis would have the best insight into what is "stamped".  Would you agree with this? 

Maybe a better statement would be: "that the sawyers who deal with the material on a daily basis would have the best insight into what qualifies to be "stamped".....

As mentioned you can mill out a 2x4 with a three inch knot in it..... but will it be strong enough to hold up a roof in a wall?..... not likely.....

So you have to understand the grade rules....

And it's not rocket science.... you just have to start with the rules and read them and then watch your timbers and see how they apply....

When you have a butt log from an eastern white pine tree you have the best chance to make that log a "grade 2" or better log. As usually the bottom logs have the least amount of branches and therefore the least amount of defects...

When you get into milling the second log up on a tree and then the third log up you have to start watching for larger branch knots and how they will effect the grade.

Another thing after knot size you have to consider is "slope of grain".

It is hard to understand and see the actual "slope of grain" in a timber, but if you are milling timbers from logs that are the straightest you can find then the "slope of grain" shouldn't come into play.

can you tell its "grade" by the way it behaves when it is sawn?

When sawing a log, and it reacts to being sawn by moving on the mill, this is an indication that there is stress in the log. You need to reduce the stress evenly so that the timber ends up the size you want it. And that the lumber coming off the sides of the timber, hopefully, is usable lumber. You don't want to waste it, but sometime it is waste due to the thickness problems...

White pine usually doesn't have a lot of stress in it that will cause the timber to move while sawing. Hardwoods however do.

To reduce the stress evenly you don't cut to deep into one face when you see the timber/log moving on the mill. Or when the boards being cut move as you're cutting them.

If you're cutting an 8x8 timber and as you're cutting it you're making boards from the outside of the log, and one of the boards lifts up off the log as you're cutting it, then there is stress in the log.
If the board shifts right or left as you're cutting it then there is stress in the log.
As soon as I see this I may stop cutting this face and move to another face or the opposite face to release some stress over then and then come back to this face later on.

To do this you have to plan your cuts and understand "how" you're going to get a timber out of the log.

I'm not sure if I've ever said this here, but I would suspect I have, but you have to plan your last cut first.

Some people have a hard time understand this.
How can you plan your "last" cut first?

To explain this will take several posts and lots of pictures.
I don't have time today to do it, but I'll put it on my "to do" list and work on it...

Jim Rogers