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The Woodshop Machines page has machine specific information including controls, usage and safety PDF's for each machine. This page is for any general woodworking topics.

Wood Movement

Wood MovementWood moves with changes in relative humidity. Wood expands/contracts, even changes shape, as the relative humidity increases/decreases. Most of the change is tangential to the growth rings (width and/or thickness), the lengthwise change is insignificant. Flat sawn wood (typical) moves mostly in width, e.g. a 3% increase/decrease in relative humidity will cause a 24" wide flat-sawn pine board to grow/shrink 3/16".

Moisture Content and Movement (image source)
How to Calculate Wood Shrinkage and Expansion (pine example source)
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9 Steps to Sizing Rough Lumber
9 Steps to Sizing Rough LumberThe article applies to any board processing done to clean, straighten and square the faces and edges. The primary steps start at number four:
  • Joint the most concave face of the board flat
  • Plane the other face (parallel faces)
  • Joint the most concave edge
  • Rip the other edge (parallel edges)
  • Joint the ripped edge clean
The Makerspace jointer can only flatten boards up to 6" wide. Wider boards can be edge jointed and ripped to fit (steps 2 and 3) or surfaced using other means. Using a hand plane or router for surfacing is a time consuming task. Using a jointer and planer t-square has possibilities. Image is from a lumber sizes article
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Wood Lumber Cuts
Wood Lumber Cuts "Logs are cut into boards in a few different ways, which produce different characteristics and amounts of waste. This article covers the different types of cuts for wood boards."

In a nutshell, most lumber is plain/flat sawn - the log is simply sliced into planks. Plain sawn boards are the least expensive and the most likely to warp. The straight linear grain of quarter sawn lumber is more stable and more expensive. Rift sawn is the only way to achieve a quarter sawn appearance when the wood has pronounced medullary rays (slide 14).

Image is from another article about lumber cuts.
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Reading Grain Direction
Reading Grain DirectionGetting a good surface finish on wood depends on grain direction. To minimize tearout, feed lumber into the jointer or planer with the grain angling away from the cutterhead. Determining grain direction can be tricky and the linked Popular Woodworking article covers the topic in depth.

Wood is a bit like fur, run wood into a cutterhead against the grain and the knives will try to lift the grain. Not being able to lift the grain, the knives will have a tendency to grab and tear out bits of wood (tearout).

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Wood warping
Wood warping"The types of wood warping include:
  • bow: a warp along the length of the face of the wood
  • crook: (also called wain) a warp along the length of the edge of the wood
  • kink: a localized crook, often due to a knot
  • cup: a warp across the width of the face, in which the edges are higher or lower than the center of the wood
  • twist or wind: a distortion in which the two ends do not lie on the same plane. Winding sticks assist in viewing this defect."
When processing lumber on the jointer; the face is flattened with the concave face of the bow, cup or twist against the bed. The edge is easiest to straighten with the concave edge of the crook, kink or twist against the bed. To help prevent binding and kickbacks when cross cutting warped boards, the concave face and edge should always face away from the table and fence of the saw. Ripping to width is also done concave face up, but requires a straight (jointed) edge against the fence. With sheet goods, a slight concave against the fence is fine (better than a convex edge).
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