H-2 Task 2 Flashcards
1) grain:
2 types of wood form annual growth rings?
Spring wood and summer wood
- Spring grows fast and is pourous
- Summer grows slower and is dense
Edge grain lumber:
What will edge grain produce, better than flat grain?
Edge grain will shrink how? Compared to flat grain
Resist wear better than lumber with flat grain
Shrink less across its width than flat grain lumber of the same width
What angle does the annual growth rings have to be for edge grain lumber?
What angle does the annual growth rings have to be for flat grain lumber?
Greater than 45 degrees
Less than 45 degrees
Flat or plain sawn: Quarter sawn
How is flat sawn cut a log?
How is quarter sawn cut a log?
Cut boards through the full width of the log, most of the boards will be flat grain
Cutting the log into quarters first and then cutting each quarter into boards that are all edge grain
Which is common sawing method for framing lumber?
Which is method is used to produce high end finishing lumber?
Flat plain sawn= flat grain most of the boards
Quarter sawn= edge grain all boards
Drying:
How much moisture content will freshly cut logs have?
What is freshly cut logs considered until its dried?
What moisture content for framing have to be?
45% for cut logs
Considered green until its dried
19% for framing
framing lumber is either kiln dried or air dried
What does s-dry mean?
What does s-grn mean?
Lumber is kiln-dried, dried in steam oven. Its surfaced after kiln drying (s-dry)
Lumber is air-dried, lumber surfaced green is surfaced to a slightly larger dimension than kiln-dried (s-grn)
What are these abbreviations? S1S S1S2E S2S S2S1E S1E S4S S2E
Surfaced 1 side surfaced 1 side 2 edge
Surfaced 2 side surfaced 3 side 1 edge
Surfaced 1 edge surfaced all 4 sides
Surfaced 2 edge
Re-sawn boards
What will S4S 2” re-sawn to 1” be?
Normally not much demand for 2x8 and 2x10 that is grade #3, what can be done to these boards for reuse?
S1S2E 1”
Resawn into 3/4” boards, used as sheathing or fencing
Why is lumber surface treated at the mill?
Why is lumber packed tightly at the mill?
To give cosmetic protection from mould and sap stains
Because moisture is usually present
Pressure treated:
What is used for treating lumber for outdoor uses?
What is no longer used?
What else does the treatment protect against?
ACQ (alkaline copper quaternary)
CCA (chromater copper arsenate)
Chemicals protect against fungi that cause rot and agaisnt wood eating insects (termites)
First and Second (FAS) Boards graded as FAS have: Minimum width? Minimum lenth? Clear cutting that is atleast? What percent free from defects? No knots wider than?
Minimum width of 6”
Minimum length of 8’
4” wide by 5’, or 3” wide and 7’ long
83% of the face free from defects
No knots wider than 1/3 of the width of the board
Who regulates lumber size and grades for wood frame construction?
NLGA (national lumber grades authority)
Surfaced dry:
What moisture content will it have leaving the mill?
When is s-dry lumber planed to dimension?
19% or less, however it can absorb moisture from damp conditions
After it has been through the kiln dried process
Needs to be keep dry when stored to stay within the moisture allowance (19%) for framing lumber
Surfaced dry nominal to actual 2” 4” 6” 8” 10” 12”
1 1/2”
3 1/2”
5 1/2”
7 1/4”
9 1/4”
11 1/4”
Surfaced green nominal to actual 2” 4” 6” 8” 10” 12”
1 9/16”
3 9/16”
5 5/8”
7 1/2”
9 1/2”
11 1/2”
*5 5/8” is the only different one
Why does s-green 2-4” have an extra 1/16” and 8, 10, 12” have an extra 1/4”?
Can you mix s-dry and s-grn for the same framing project?
Various sizes is in anticipation of shrinkage-wider boards will have greater shrinkage
No it will be problematic
Lumber sizes for:
Boards?
Light framing?
Joists and planking?
1” thickness by 2”-12” wide
2-4” thick by 2-4” wide
2-4” thick by 6”-12” wide
Lumber sizes for:
Beams and stringers?
Posts and timbers?
5” or more in thickness and more than 2” greater in width than in thickness
5” by 5” in cross sectional dimensions, they must not be 2” greater in width than in thickness
What are the 2 grading methods?
Structural light framing is divided into four grades. What is the percentage of strength of a clear defect free board Sel str? No.1? No.2? No.3?
Visual grading, machine stress rating
Sel str 67%
No 1 55%
No 2. 45%
No 3. 26%
What does a visual grading process require?
What are the three stamps for drying?
Inspect every board thats sawn and graded, checks for defects snd then stamps.
S-Grn, S-dry and sometimes KD (kiln dried)
What does a machine stress rating procedure require?
What framing members use machine stress rated lumber?
Lumber passes through a device that messures how much the actual piece of lumber will bend or flex under a given load
Engineered wood trusses
Light framing divided into four catagories What percent of clear defect free board Construction? Standard? Utility? Economy?
Const 34%
Stand 19%
Utility. 9%
Econ. (Not rated strength)
