No we want to use NSW Blackbutt.
But I wouldn't saw WA Blackbutt has a life expectancy of 5-10 years.
Tas Oak is softer and that lasts 10+
Good
Based on a publication form National Association of Forest Industries:
WA Blackbutt (bot. name Eucaluptus Patens) has Janka of 6.9, belongs to the SD5 strength group and "L" for toughness. Tangential Shrinkage = 10
Blackbutt (bot. name Eucaliptus Pilularis) has Janka of 8.9, belongs to the SD2 strength group and "M" for toughness. Tangential Shrinkage = 7.3
Blackbutt New England (bot. name Eucaliptus Andrewsii) has Janka of 9.2, belongs to the SD3 strength group and "M" for toughness. Tangential Shrinkage = 11.4
All of them have average density between 850 and 900. All belong to the durability class 2.
The publication explains these parameters as:
Janka (the higher, the better) is resistance to indentation - i.e. jumping while wearing heels or dropping a hummer. Quite often this number is used to describe the overall strength and toughness of the timber which is a mistake. Ability of a car to withstand the heal storm does not guarantee a less impact of a collision accident.
Strength is the measure of stiffness. SD5 = load of up to 11 MPa, SD3 up to 17 MPa, SD2 up to 27MPa ( I believe concrete class "H" is 25 MPa)
Toughness is a synonym to the impact strength - ability to resist shocks and blows. L = up to 15 Nm, M = between 15 and 25, H = 25 and above
Durability 2 means 15-25 years of life (so yeah, I was wrong in my initial post )
Tangetnial Shrinkage is the rate of movement what timber responds to the changes in moisture.