Applied Lumber Technical Properties
This is kind of a review of episode 5 but ideally a bit more applied look at what all those number mean when it comes to actually working with wood. In this episode I look at what I find are the most important numbers to consider and the tests that give us these numbers. Just remember wood is orthotropic which means its strength properties are not the same in all directions. Its is also anisometric (or anisotropic) which means it moves differently in all directions. That second term is just to impress people at dinner parties.
- Hardness (check out episode 29 on Janka Hardness)
- Density/Specific Gravity
- Weight
- MOR/MOE (check out episode 35 on MOR/MOE)
- T/R ratio
- Shearing Strength (check out episode 30 on Shearing Strength)
- Crushing Strength
More information on these properties, what they mean, and the tests performed to get the actual data can be obtained in the Wood Handbook published by the Forest Products Laboratory. Download your copy today for outstanding bedtime reading! You will find that many other countries have developed a similar "handbook" with a bit of creative Googling.
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Stephen A Malcom says
Shannon, could you comment or perhaps do an episode on how a wood may deviate significantly from the technical properties we see on Wood Database? Specifically, I’m thinking like how plantation teak differs from true Myanmar teak, or how a piece of old growth pine will have really dense growth rings vs a 2×4 that has really widely spaced rings?
shannon says
Sure but I don’t know that there will be many generalizations in this line of thought. I can definitely speak to your two specific examples. But let me think about some “trends” that could effect the working properties that might apply across many species and growth environments. Soil Chemistry has a major role to play in this and I talk about that particular episode. But growth rate is a good topic to discuss as there is a distinct difference between hardwoods and softwoods that isn’t widely understood.