Part 5 - Inspection and Grading

by Bill Tindall

Grading Lumber

After the log has been converted to boards they are inspected by a lumber grader. The grader has two tools, a lumber rule in his left hand and a crayon on the end of a stick in his right hand. The lumber grader’s first job is to determine if the value of the board can be improved by cross cutting it into a shorter length. For example, the log may have been 12' 6" long yielding boards 12' 6" long. (note: logs are cut 6" longer than their nominal even foot length. This extra length enables the boards to be double end trimmed to 1" over the nominal foot length to remove end checks which may have occurred during storage of the logs on the log yard). Suppose one of these boards had a large knot at 11' 6". By trimming the board at 11' 1" the value of the board would be improved because it would now become a higher grade board and worth more, even though a foot of this board has been scrapped. The lumber grader would make a trim mark with his crayon to indicate to the trimming operation to trim this board at 11' 1" length.

The next task is to determine the lumber grade of the board after trimming, or as is, if the board is not to be trimmed. The grader uses his lumber rule to turn the board and to make measurements of the board to assist in determining grade. The grade is indicated on the board with a mark from the crayon—“O” for top grade, “\” for the next lower grade and “X” for next lowest. The final task of the grader is to measure the bd ft of the board and enter it and the board grade on a tally sheet described below.

This picture shows the least sophisticated lumber inspection I have seen. Boards come from the mill, get dumped at the head of the green chain, and move past the grader for inspection. After he makes his marks, one of the helpers trims as needed with a chain saw. Finally lumber is pulled from the chain and stacked into shipping packs by length and grade. When about 1000 bd ft has accumulated of one grade and length, the pack is banded and loaded onto a truck for a trip to the dry kiln.

In the largest mills everything except the grading is automated. Once the grader makes his marks the board passes under automated cross cut saws which drop to trim to the marks. Robots remove the lumber from the green chain and stack it by grade and length. It is likely that scanners and a computer will become common for inspection in the most automated mills of the future.

We saw how turning the log to saw for best yield results in lumber of random width. The trimming operation then results in lumber in lengths ranging from 6' to 16' in one foot increments. For this reason hardwood lumber is most frequently sold as random lengths and widths. However, lumber is assembled into packs of nearly the same lengths. So, for example, a pack of 12 foot lumber will contain 11 and 12 foot long lumber, or maybe even 9, 10, 11, and 12 foot long lumber.

Tallying Lumber

The process of measuring grade and quantity of lumber in a pack is called tallying. The bd ft in the board is determined with the lumber rule, shown at right. This process always fascinated our customers. The rule is hooked over the edge of the board and the bd ft in the board is read from the rule.

The scale used to determine bd ft depends on the length of the board. The top scale of this rule is for 16' lumber, the next for 14', 10', and 12'. These length values are stamped on the other end of the rule next to the handle. Odd lengths are on the other side of the rule. The dots next to or between digits are located at that bd ft value and the vertical marks are located at the ½ bd ft values.

If the board falls less than half way to the next increment one rounds down its measure, or rounds up if it is greater than half way to the next value. If it falls at exactly half, one alternates rounding up and down. For example, if this board was 16' long it would contain 10 bd ft of 4/4 lumber, if it was 14' long it would contain 9 bd ft, if it was 10' long it would contain 6 bd ft and 12' long it would contain either 7 or 8 bd ft because the edge of the board falls on the ½ mark between 7 and 8.

The values stamped in the top metal part of the rule are for determining thickness, by quarters. Lumber sawn as 4/4 is actually cut about 11⁄8" thick such that it winds up 1" after shrinking in the drying operation. Lumber sawn as 8/4 is actually cut 2¼" thick for this same reason.

For each board the grader makes a mark in the tally sheet next to the corresponding bd ft value. There are ten boards per box—nine dots and a slash complete the box of ten. A filled out tally sheet is shown at right. I don’t have an official printed sheet any more but they are easy to make, as shown. This pack of 5/4 red oak has 27 pieces that are 6 bd ft as measured by the rule, 22 pieces that are 7 bd ft, etc., for a total tallied as 4/4 lumber of 867 bdft. This tally is then multiplied by 5/4 to get the tally as 5/4 lumber. If this was kiln dried lumber it is common to then have this tally multiplied by 1.07. All the wholesale packs of lumber we ever bought had this 7% added to the actual tally.

Why? It all goes back to grading convention, I think. Lumber grade is typically determined before drying. Defects which occur or show up after drying are charged off to whomever is buying the lumber. Because grade is determined before drying, I suppose it became convention to also determine bd ft before drying. Since lumber shrinks about 7% during drying there should be no mystery as to where the tariff originated.

Retail customers go crazy if the seller adds 7% to a tally, so we never did it in a way the customer saw it. It never bothered me because I expected it and I just adjusted our cost of the lumber up 10% to cover this 7% shrinkage and a bit of down grade from drying. We then billed on actual measured bd ft.

The National Hardwood Lumber Association (NHLA) instruction book for grading lumber is more than 100 pages in length. I considered, but gave up on, the daunting task of trying to summarize its Byzantine rules. But there is one point I want to make as a result of trying to occasionally sell hardwood lumber to retail customers. First, some background for this point.

Hardwood lumber grades are set by the NHLA in cooperation with producers (sawmills) and buyers (furniture factories). I don’t know the actual number, but I suspect that retail hardwood lumber sales are not even 1% of total sales. It follows that the small volume furniture makers’ needs and concerns have little influence on how lumber is graded or marketed on the wholesale scale.

Furniture factories historically have been the main customers for hardwood lumber. They build furniture by ripping and cross cutting boards into smaller pieces and then gluing them back to make parts sized to fit their needs. Because the factories break lumber down into cuttings, lumber is graded by what fraction of the board will yield these clear cuttings and how big these cuttings will be. The better grade board will yield a larger fraction of clear cuttings and these cuttings will be larger in size.

There are numerous possible lumber grades. In decreasing order of yield of clear cuttings they are: Firsts, Seconds, First & Seconds 1 Face, Selects, #1 Common, #2A Common, #2B Common, #3 Common, etc. In spite of these possible grades I have never seen a pack of Firsts for sale. The highest grade of lumber actually available in a wholesale pack is a combination of the first three grades and this grade is abbreviated FAS1F and Better, which translates firsts & seconds, 1 face and better. When small logs are all that is available—for example in cherry and maple—it is common that the best grade that can be bought wholesale is Selects and Better (Selects allows more narrow lumber than the higher grades). Pallet lumber is #3 Common, and #2 Common looks like knotty pine.

And now to the point of all this. A factory making end table tops would get essentially the same yield from a clear board 12" x 12' as they would from a 12" x 12' with a small knot or two. Hence, it matters not to the furniture factory that these two boards would fall in the same top grade. However, these two examples would not be valued the same by a retail customer.

The best grade of lumber that can be bought in commercial quantities is a far cry from the clear lumber most retail customers expect to get for their $6/bd ft retail sale price. I will leave it to the reader to imagine the difficulty a retail operation has buying Sel & Btr cherry and trying to sell it retail. Further, imagine what would be left in this pack after retail customers were allowed to pick half the lumber out of it.