Do you know the main hard woods? What about soft woods? Here you will find a hardness rating with some of the most common types
One of the usual criteria for classifying woods is according to their hardness, that is, whether they are hard or soft. And this time we want to go a little deeper into this topic.
Hardwoods generally belong to tree species whose growth is slow and the result is dense wood. A feature closely related to hardness. On the other hand, softwoods belong to fast-growing species and tend to have a much lower density.
To give you an idea, some species can be explored in 4 years, such as balsa wood. For others, such as eucalyptus, which is not exactly one of the densest species, it will take about 15 years, more or less the same as an oak.
How is wood hardness measured?
There are multiple techniques that help us to catalog and technically differentiate hard and soft woods. Although it is possible to differentiate between two very different woods, which is more difficult at first, when they are similar woods the classification is not so simple.
Classification of woods
Two of these techniques are the most widespread (3 classification of woods):
- Janka Scale: Designed specifically for wood. And it measures the force needed to embed a small 0.444-inch metal ball half its diameter in the wood.
- Brinell hardness test. This test is used to measure the hardness of any material, not just wood. It consists of applying a force to a steel ball and measuring the slack produced.
- Monnin (UNE 56-534). This test measures the depth of indentation caused by a steel cylinder 30 mm in diameter under certain load conditions. This method is the most used in Europe.
Types of wood hardness and examples
There is simply no differentiation between hard and soft woods. There are different intermediate degrees. According to the values obtained in the Monnin hardness test:
List of hard and soft woods
|Very soft||<1.5||Raft (0.25 – 0.3) / Samba (1.2)|
|Soft||1.5 – 3||Okume (1.6) / Pine (1.8 – 2.5) / Fir (2.5) / Poplar (2.6) / Mahogany (2.7) / Larch (2.7)|
|Semi-hard||3 – 6||birch (3.1) / Iroko (3.9) / Nut (3.8) / cherry (3.2 – 4.3) / Beech (4) / Teak (4.2) / Sapelli (4.2) / ash (4.2) / Board (4.5) / Oak (4.8 – 5.8)|
|Difficult||6 – 9||Holm oak (6) / Olive (6) / Merbau (6.4) / Talí or Elondo (8.5 – 9.2)|
|Very difficult||9-20||Wengue (9.1) / Bubinga (10.2) / Jatoba (10.5) / Cumaru (eleven) / Ipe (14.6)|
If what you are looking for is to satisfy your curiosity only with a classification of the hardest woods, Follow this link. To see a wider range, you can visit our wooden encyclopedia.
There are some types of wood that can be found in varying degrees of hardness. This is the case of pine wood, of which there are many subspecies, each with its own peculiarities.