Janka Hardness Ratings
The Janka hardness test measures the hardness of wood. It involves measuring the force required to embed an 11.28 mm (0.444 in) steel ball into wood to half its diameter. This method was chosen so that the result would leave an indention 100 mm² (0.16 sq in) in size.
It is one of the best measures of the ability of a wood species to withstand denting and wear.
The higher the Janka Rating, the harder the timber is.
| Species | Janka (kN) |
| Bamboo (strand woven) | 16.1 |
| Grey Box | 15.0 |
| Ironbark | 14.0 |
| Red Mahogany | 12.0 |
| Turpentine | 12.0 |
| Spotted Gum | 11.0 |
| Brushbox | 9.5 |
| Blackbutt | 9.1 |
| Forest Reds | 9.1 |
| Sydney Blue Gum | 9.0 |
| Karri | 9.0 |
| Tallowwood | 8.6 |
| Merbau | 8.6 |
| Jarrah | 8.5 |
| Stringybark | 8.1 |
| Australian Beech | 7.5 |
| Flooded / Rose Gum | 7.5 |
| Northern Beech | 7.5 |
| Messmate | 7.1 |
| Bamboo (vertical) | 6.6 |
| Cypress Pine | 6.1 |
| New England Oak | 6.1 |
| American Oak | 6.0 |
| Bamboo (horizontal) | 5.9 |
| Tasmanian Oak | 5.5 |
| Victorian Ash | 4.5 |
| Baltic Pine | 2.9 |