Characteristics 105: Manufacturing Defects

In Characteristics 105 you will learn about defects that can occur during the manufacturing process that affect the grade of lumber.

Syllabus

105: Torn Grain

Torn Grain – an irregularity in the surface of a piece where wood has been torn or broken out by surfacing.  Torn grain is defined based on the depth of the tear.  [Standard Grading Rules for Northeastern Lumber para. 720.0 (b)]

Very light torn grain – not over 1/64” deep

Light torn grain – not over 1/32” deep

Medium torn grain – not over 1/16” deep

Heavy torn grain – not over 1/8” deep

Very heavy torn grain – over 1/8” deep

105: Raised Grain

A roughened condition of the surface of dressed lumber in which the hard summerwood is raised above the softer springwood, but not torn loose from it. Raised grain is described based on the height of the raised portion. [Standard Grading Rules for Northeastern Lumber para. 720.0 (c)]

Very light raised grain – not over 1/64”

Light raised grain – not over 1/32”

Medium raised grain – not over 1/16”

Heavy raised grain – not over 1/8”

105: Mismatch

Mismatch – an uneven fit in worked lumber when adjoining pieces do not meet tightly at all points of contact or when the surface of adjoining pieces are not in the same plane.  [Standard Grading Rules for Northeastern Lumber para. 720.0 (h)].

Slight mismatch – barely evident trace of mismatch

Very light mismatch – not over 1/64”

Light mismatch – not over 1/32”

Medium mismatch – not over 1/16”

Heavy mismatch – not over 1/8”

105: Machine Burn

The darkening of the wood due to overheating by machine knives or rolls when pieces are stopped in the machine. [Standard Grading Rules for Northeastern Lumber para. 720.0 (i)].

 

105: Machine Bite

A depressed cut of the machine knives at the end of the piece. [Standard Grading Rules for Northeastern Lumber para. 720.0 (j)].

Very light machine bite – not over 1/64”

Light machine bite – not over 1/32”

Medium machine bite – not over 1/16”

Heavy machine bite – not over 1/8”

105: Machine Gouge

A Machine Gouge – a groove cut by the machine below the desired line. [Standard Grading Rules for Northeastern Lumber para. 720.0 (k)]. 

Very light machine gouge – not over 1/64”

Light machine gouge – not over 1/32”

Medium machine gouge – not over 1/16”

Heavy machine gouge – not over 1/8”

Very heavy machine gouge – over 1/8”

 

 

105: Machine Offset

Machine Offset – an abrupt dressing variation in the edge surface which usually occurs near the end of a piece and without reducing the width or without changing the plane of the wide surface. [Standard Grading Rules for Northeastern Lumber para. 720.00 (i)]. It is described as:

Very light machine offset – not over 1/64”

Light machine offset – not over 1/32”

Medium machine offset – not over 1/16”

Heavy machine offset – not over 1/8”

Very heavy machine offset – over 1/8”

105: Marks : Knife

Knife Marks – the imprints or markings of the machine knives on the surface of 

dressed lumber. [Standard Grading Rules for Northeastern Lumber para. 720.0 (n)]. They are described as:

Very light knife marks – visible only from a favorable angle and are perfectly smooth to the touch.  

Slight knife marks – readily visible, but evident; no unevenness to the touch.

105: Marks: Wavy Dressing

Marks that are more uneven dressing than knife marks. [Standard Grading Rules for Northeastern Lumber para. 720.0 (o)].

Very light wavy dressing – not over 1/64”

Light wavy dressing – not over 1/32”

Medium wavy dressing– not over 1/16”

Heavy wavy dressing – not over 1/8”

Very heavy wavy dressing – over 1/8”

105: Saw Cuts

A cut in the lumber caused by a trim saw catching the edge of a board on the lug chain of a double end trimmer.  In many cases, the cut may not go all the way through the depth and width of the piece. [General Definitions & Instructions for Grading Eastern White Pine Boards para. 826.0]

105: Skips

Skips are areas on a piece that failed to surface clean.

Skip allowances are defined as follows:

Very light skip – not over 1/64”

Light skip – not over 1/32”

Medium skip – not over 1/16”

Heavy skip – not over 1/8”

Hit and Miss – a series of skips not over 1/16”

Hit or Miss – partially surfaced (scantness can’t be over 1/16″) or entirely rough

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