Woodworking
108 flashcards by MentisLibrary
Furniture-scale woodworking: reading wood and its movement, hand planes and chisels, sharpening, jointer and planer milling, table saw and router safety, the classic joints, glue-ups and finishing.
- What actually separates a hardwood from a softwood?
- Hardwoods come from broadleaf, flowering trees and softwoods from conifers. The label describes the tree, not the density of the wood.
- What does the Janka hardness test measure?
- The force, in pounds-force, needed to press a steel ball halfway into the wood.
- Order red oak, hard maple, black walnut, cherry and poplar from hardest to softest.
- Hard maple near 1450, red oak near 1290, black walnut near 1010, cherry near 950, poplar near 540 on the Janka scale.
- What is the difference between a ring-porous and a diffuse-porous hardwood?
- A ring-porous species puts large vessels in the earlywood, giving a strong grain pattern; a diffuse-porous species spreads small vessels evenly, giving a subtle one.
- What is the difference between heartwood and sapwood?
- Heartwood is the dead inner wood, usually darker and more decay resistant; sapwood is the living outer wood that carried sap.
- What is quartersawn lumber?
- Lumber cut so the growth rings meet the face at roughly 60 to 90 degrees, giving straight grain and, in oak, ray fleck.
- How does a flatsawn board tend to distort as it dries?
- It cups away from the heart, so the face that lay nearer the bark becomes hollow.
- In which direction does wood move most, and in which does it move least?
- Most tangentially, around the growth rings; about half that radially, across them; and almost none along the length of the grain.
- What is equilibrium moisture content?
- The moisture content wood settles at for a given temperature and humidity. It keeps shifting as the seasons do.
- Why do you sticker and acclimate lumber before milling it?
- So the boards reach the shop's moisture content and release their internal stress before you cut any joinery.
- What do the hardwood markings 4/4, 5/4 and 8/4 mean?
- Rough thickness in quarter inches: 4/4 is one inch, 5/4 is one and a quarter, 8/4 is two inches, all measured before surfacing.
- What does the hardwood grade FAS mean?
- Firsts and Seconds, the top NHLA grade: boards at least 6 inches wide and 8 feet long that yield at least 83 percent clear cuttings.
- What causes figure such as curl, quilt and birdseye?
- Local distortions in the grain that catch and release light differently as you move around the board.
- What are checks, shakes and wane in a board?
- A check is a split along the grain, usually at an end; a shake is a separation between growth rings; wane is bark or missing wood along an edge.
- Why does a board sometimes pinch the blade or bow the instant you rip it?
- Internal stress left from drying is released by the cut, and the two halves move.
- How do MDF, particleboard and plywood differ?
- MDF is fine wood fibre pressed with resin, particleboard is coarser chips, and plywood is thin veneers glued in alternating grain directions.
- What makes Baltic birch plywood different from ordinary plywood?
- It is built from thin birch plies of even thickness with very few voids, so the edge is clean enough to leave exposed.
- What do the bench plane numbers 4, 5 and 7 tell you?
- Size and role: a No. 4 is a 9 inch smoothing plane, a No. 5 a 14 inch jack, and a No. 7 a 22 inch jointer.
- Why does a jointer plane have such a long sole?
- The long sole rides on the high spots and cannot drop into the hollows, so it shaves the peaks down until the surface is flat.
- What sets the cutting angle of a standard bevel-down bench plane?
- The frog, at about 45 degrees. The iron sits bevel down, so the bevel angle does not change the cutting angle.
- What does the chipbreaker on a bench plane actually do?
- Set close behind the edge, it bends the shaving upward as it forms so the shaving cannot lift and split the wood ahead of the cut.
- How does a low angle block plane differ from a standard one?
- Its iron beds at about 12 degrees rather than about 20, giving a lower overall cutting angle.
- How does a card scraper cut?
- A burnished hook rolled along its edge takes a fine shaving, exactly as a very small plane iron would.
- What is the difference between a Western and a Japanese handsaw?
- A Western saw cuts on the push stroke with a thicker, stiffer plate; a Japanese saw cuts on the pull stroke, which allows a very thin plate.
- How do rip teeth differ from crosscut teeth?
- Rip teeth are filed straight across like tiny chisels to pare along the fibres; crosscut teeth are filed at an angle so their points sever fibres like knives.
- Why is a dovetail saw filed rip?
- Because dovetail cuts run mostly along the grain, down the length of the board, which is what a rip pattern is for.
- What is the difference between a bevel-edge chisel and a mortise chisel?
- A bevel-edge chisel has thin angled sides for reaching into corners; a mortise chisel is thick and square in section so it can take levering and mallet blows.
- Why mark joinery with a knife instead of a pencil?
- A knife severs the surface fibres, so the line sits exactly where the joint ends and a chisel or saw can register in it.
- What does a marking gauge do that a rule cannot?
- It scribes a line a fixed distance from a reference edge, identically on every part, with no number to read.
- What is a mortise gauge?
- A marking gauge with two pins that scribes both walls of a mortise, or both cheeks of a tenon, in one pass.