Dundas blackbutt is a small to medium-sized tree scattered in two separate areas. One occurrence is from north-west of Norseman east to the Fraser Range and southwards, and the other north of Coolgardie.
Heartwood is light brown to reddish colour. Sapwood is paler. The timber has a moderate grain.
Green density is the density of wood in the living tree, defined as green mass divided by green volume, and useful for estimating transport costs. It varies with season and growing conditions.
Air-dry density is the average mass divided by volume at 12 per cent moisture content (this is the average environmental condition in the coastal capital cities around Australia).
Basic density is oven-dry mass divided by green volume. This measure has the advantage that moisture content variations in the tree during the year are avoided.
:Air-dry density is about 1100 kg/m3.
Tangential and radial shrinkage are estimated as about 6.0 and 4.5 per cent respectively.
Goldfields craftsmen rate Dundas blackbutt as good for turning, machinability, boring, screwholding, stability, sanding, gluing, and finishing.
Minimum values (MPa) for strength groups for green and seasoned timber come from Australian Standard AS2878-1986 'Timber - Classification of strength groups'. In grading structural timber, each species is allocated a ranking for green timber of S1 (strongest) to S7, and for seasoned timber SD1 (strongest) to SD8.
MOR is modulus of rupture or bending strength, MOE is modulus of elasticity or 'stiffness', and MCS is maximum crushing strength or compression strength. Hardness refers to the Janka hardness test and is a measure of resistance to indentation.
Minimum values (Mpa) for green timber
Strength Property | S1 | S2 | S3 | S4 | S5 | S6 | S7 |
---|---|---|---|---|---|---|---|
MOR | 103 | 86 | 73 | 62 | 52 | 43 | 36 |
MOE | 16300 | 14200 | 12400 | 10700 | 9100 | 7900 | 6900 |
MCS | 52 | 43 | 36 | 31 | 26 | 22 | 18 |
Minimum values (Mpa) for green timber
Strength Property | SD1 | SD2 | SD3 | SD4 | SD5 | SD6 | SD7 | SD8 |
---|---|---|---|---|---|---|---|---|
MOR | 150 | 130 | 110 | 94 | 78 | 65 | 55 | 45 |
MOE | 21500 | 18500 | 16000 | 14000 | 12500 | 10500 | 9100 | 7900 |
MCS | 80 | 70 | 61 | 54 | 47 | 41 | 36 | 30 |
Where test data were available, they are shown in bold print. Most values are from Bootle (1983), Wood in Australia. Types, properties and uses. (McGraw-Hill), or Julius (1906), 'Western Australian timber tests 1906: The physical characteristics of the woods of Western Australia'.
Where no strength data were available, air-dry density was used in accordance with the Australian Standard AS2878-1986 Timber - Classification of strength groups to predict the strength group. Consequently, the strength values quoted are from the above two tables.
:Green and dry strength groups are (S2) and (SD2). The brackets indicate conservative provisional ratings based on the air-dry density. The more important strength properties based on strength group are given in the table below.
Property | Units | Green | Dry |
---|---|---|---|
Modulus of Rupture | MPa | 86 | 130 |
Modulus of Elasticity | MPa | 14200 | 18500 |
Max Crushing Strength | MPa | 43 | 70 |
Hardness | KN | - | 17.6 |
Limited availability because of the scattered nature of the resource.
The timber has potential for most craft use.