Janka hardness test
The Janka hardness test measures the resistance of a sample of wood to denting and wear. It measures the force required to embed an 11.28mm (.444 in) steel ball into wood to half the ball's diameter. This method leaves an indentation. A common use of Janka hardness ratings is to determine whether a species is suitable for use as flooring.
The hardness of wood varies with the direction of the wood grain. Testing on the surface of a plank, perpendicular to the grain, is said to be of "side hardness". Testing the cut surface of a stump is called a test of "end hardness".
The results are stated in various ways, which can lead to confusion, especially when the name of the actual units employed is often not attached. In the United States, the measurement is in pounds-force (lbf). In Sweden it is in kilograms-force (kgf), and in Australia, either in newtons (N) or kilonewtons (kN). Sometimes the results are treated as units, for example "660 Janka".
The Janka Hardness test results tabulated below were done in accordance with ASTM D 1037-12 testing methods. Lumber stocks tested ranges from 1" to 2" thick. The tabulated Janka Hardness numbers are an average. There is a standard deviation associated with each species, but these values are not given. It is important to note no testing was done on actual flooring. Other factors affect how flooring performs: the type of core for engineered flooring such as pine, HDF, poplar, oak, birch; grain direction and thickness; floor or top wear surface, etc. The chart is not to be considered an absolute; it is meant to help people understand which woods are harder than others.
| Species | Janka Hardness (pounds-force) |
|---|---|
| Australian Buloke | 5060[1] |
| Lignum vitae / Guayacan / Pockenholz | 4500 |
| Patagonian Rosewood / Curupay / Angico Preto / Piptadenia Macrocarpa / Brazilian Tiger Mahogany | 3840 |
| Brazilian Olivewood | 3700 |
| Brazilian Ebony | 3692 |
| Ipê / "Brazilian Walnut" / Lapacho | 3684 |
| African Pearlwood / Moabi Sometimes: Brazilian Cherry "Lite" | 3680 |
| Grey Ironbark | 3664 |
| Bolivian Cherry | 3650 |
| Lapacho | 3640 |
| Cumaru / "Brazilian Teak" sometimes: "Brazilian Chestnut," "Tiete Chestnut," "South American Chestnut," "Southern Chestnut" | 3540 |
| Ebony | 3220 |
| Brazilian Redwood / Paraju / Massaranduba | 3190 |
| Yvyraro | 3040 |
| Stranded/woven bamboo | 3000 |
| Bloodwood | 2900 |
| Red Mahogany, Turpentine | 2697 |
| "Southern Chestnut" | 2670 |
| Spotted Gum | 2473 |
| Brazilian Cherry / Jatoba | 2350 |
| Mesquite | 2345 |
| "Golden Teak" | 2330 |
| Santos Mahogany, Bocote, Cabreuva, Honduran Rosewood | 2200 |
| Pradoo | 2170 |
| Brazilian Koa | 2160 |
| Sucupira sometimes "Brazilian Chestnut" or "Tiete Chestnut" | 2140 |
| Brushbox | 2135 |
| Osage Orange[2] | 2040 |
| Karri | 2030 |
| Sydney Blue Gum | 2023 |
| Bubinga | 1980 |
| Cameron | 1940 |
| Tallowwood | 1933 |
| Merbau | 1925 |
| Amendoim | 1912 |
| Jarrah | 1910 |
| Purpleheart | 1860 |
| Goncalo Alves / Tigerwood | 1850 |
| Hickory / Pecan, Satinwood | 1820 |
| Afzelia / Doussie / Australian Wormy Chestnut | 1810 |
| Bangkirai | 1798 |
| Rosewood | 1780 |
| African Padauk | 1725 |
| Blackwood | 1720 |
| Merbau | 1712 |
| Kempas | 1710 |
| Black Locust | 1700 |
| Highland Beech | 1686 |
| Wenge, Red Pine, Hornbeam | 1630 |
| Tualang | 1624 |
| Zebrawood | 1575 |
| True Pine, Timborana | 1570 |
| Peroba | 1557 |
| Sapele / Sapelli, Kupa'y | 1510 |
| Curupixa | 1490 |
| Sweet Birch | 1470 |
| Hard Maple / Sugar Maple | 1450 |
| Caribbean Walnut | 1390 |
| Coffee Bean | 1390 |
| Natural Bamboo (represents one species) | 1380 |
| Australian Cypress | 1375 |
| White Oak | 1360 |
| Tasmanian Oak | 1350 |
| Ribbon Gum | 1349 |
| Ash (White) | 1320 |
| American Beech | 1300 |
| Red Oak (Northern) | 1290 |
| Caribbean Heart Pine | 1280 |
| Yellow Birch, Iroko | 1260 |
| Movingui | 1230 |
| Heart Pine | 1225 |
| "Brazilian Mesquite" / Carapa Guianensis | 1220 |
| Larch | 1200 |
| Carbonized Bamboo (represents one species) | 1180 |
| Teak | 1155 |
| Cocobolo | 1136 |
| Brazilian Eucalyptus / Rose Gum | 1125 |
| Makore | 1100 |
| Siberian Larch | 1100 |
| Peruvian Walnut | 1080 |
| Boreal | 1023 |
| Black Walnut/North American Walnut | 1010 |
| Cherry | 995 |
| Black Cherry, Imbuia | 950 |
| Red Maple | 950[3] |
| Boire | 940 |
| Paper Birch | 910 |
| Eastern Red Cedar | 900 |
| Southern Yellow Pine (Longleaf) | 870 |
| Lacewood, Leopardwood | 840 |
| African Mahogany | 830 |
| Mahogany, Honduran Mahogany | 800 |
| Parana | 780 |
| Sycamore | 770 |
| Shedua | 710 |
| Silver Maple | 700[4] |
| Southern Yellow Pine (Loblolly and Shortleaf) | 690 |
| Douglas Fir | 660 |
| Western Juniper | 626 |
| Alder (Red) | 590 |
| Larch | 590 |
| Chestnut | 540 |
| Hemlock | 500 |
| Western White Pine | 420 |
| Basswood | 410 |
| Eastern White Pine | 380 |
| Balsa | 100 |
| Cuipo | 22[1] |
References
- ↑ 1.0 1.1 Johnny W. Morlan. "Wood Species Janka Hardness Scale/Chart By Common/Trade Name A - J". The World's Top 125 Known Softest/Hardest Woods. Retrieved 20 December 2011.
- ↑ http://www.customworkshop.biz/wood_charts.html
- ↑ "Red Maple". The Wood Database.
- ↑ "Silver Maple". The Wood Database.
External links
- Janka Hardness Scale For Wood Flooring Species
- Janka Hardness Scale For Wood - Side Hardness Chart of Some Woods
- The World's Top 125 Known Softest/Hardest Woods
- USDA - Wood Handbook - Wood as an Engineering Material
- USDA - Janka Hardness Using Nonstandard Specimens
- Janka Hardness Scale For Hardwood Flooring
