Grade Application 201: Knots and Wane

In 201 you will learn about the maximum size Knots and amount of Wane permissible in each NELMA grade of Eastern White Pine.

Syllabus

Grade Application 201: Black Knots

This chart depicts the largest size Black Knots permissible in each grade according to nominal board width. To properly measure a knot, take a measurement of the width and a measurement of the length, add the two measurements together and divide the total by two to get the average diameter of the knot.

(Length + Width)/2 = Average Knot Diameter

To see a demonstration of a spike knot measurement, click on the instructional video segment below.

 

Black Knot Size by Nominal Width
Grade  Knot Quality 4” 6” 8” 10” 12”+
C Select Sound and Tight One pin knot (1/2″ or smaller) per 4 surface feet
D Select Sound and Tight     One pin knot (1/2″ or smaller) per 1 surface foot*
Finish Sound and Tight 5/8” 3/4” 3/4″ 7/8” 7/8”
Premium Generally Sound and Tight** 3/4” 1” 1-1/4” 1-1/2” 1-1/2”
Standard Any Quality 1-3/4” 2-3/4” 3-5/8” 4” 4”
Industrial Any Quality Not Limited by Grade

* In an occasional piece, one small (maximum 3/4″), sound, tight knot permitted. This knot will be counted as two pin-knots when determining the number of knots permitted in the piece.

** Further information regarding Knot Quality will  be discussed in Level 300.

 

Grade Application 201: Red Knots

This chart depicts the largest size Red Knots permissible in each grade according to nominal board width. Red Knots are measured by the same method as Black Knots, which you learned in the previous Black Knot course.

 

Grade Red Knot Size by Nominal Width
4” 6” 8” 10” 12”+
C Select In an occasional piece, one small Red Knot (3/4″)
D Select Pin Knot 1/2″ or Smaller
Finish 1-1/4” 1-1/2” 2” 2-1/4” 2-1/2”
Premium 2” 2-1/2” 3″ 3-1/4” 3-3/4”
Standard 2-3/8” 3-3/4” 4-7/8” 6” 6”
Industrial Not Limited by Grade

  

 

Grade Application 201: Wane

The presence of Wane automatically dictates the reverse face; the opposite face becomes the grade face.  Measurements of Wane on a board are based on actual size, not nominal.  The following chart demonstrates the limiting provisions for Wane across the various grades.  A visual representation of Wane limitations for each grade is provided in the image to the right (Click on the image to enlarge, then click anywhere outside the image to return to course page).   View the video below to learn how to measure Wane.

 

Grade Actual (not nominal) Size Limiting Provisions
Thickness Width Length
C Select 1/2 the thickness 1/8 the width ***1/4 the length on one edge on the reverse face only
D Select 1/2 the thickness 1/4 the width 1/4 the length on one edge or equivalent on two edges on the reverse face only
Finish 1/2 the thickness 1/4 the width 1/4 the length on one edge on the reverse face only
Premium 1/2 the thickness 1/4 the width 1/4 the length on one edge or equivalent on two edges on the reverse face only
Standard 2/3 the thickness 1/4 the width 1/2 the length on one edge or equivalent on two edges on the reverse face only
Industrial 3/4 the thickness 1/2 the width 1/2 the length Full width or thickness wane up to 1/2” scant is permitted for 1/4 of the length

***Tips from the Inspector: Two quick methods for determining 1/4 the length: 1.) Multiply the length of the board in feet by 3; this will give you 1/4 the length in inches (L’ x 3 = 1/4 L in inches) or  2.) Simply divide the length of the board by 4 to get your answer in feet (L’ / 4 = L in Feet). The first method will bring simplicity to determining lengths on pieces that do not divide evenly.  You’ll find that either method will work in any situation, and you can decide which works best for you.

Note:  Applying the wane limitations to a board that contains wane on opposing edges will be covered in Section 300.

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