African Blackwood
African Blackwood or Grenadilla (botanical name Dalbergia melanoxylon) has been traditionally used in instrument making for many years. In the manufacture of woodwind instruments its use is second to none.
The timber has a very good grain structure and is a very dense. This means that it is possible for the wood to accept pillars for mechanism without the inherent weakness of some softer materials.
This density also gives the instrument a clarity of sound which is unrivalled.
African Blackwood comes from the dry regions of Africa. The musical instrument trade sources mainly from Kenya, Tanzania and Mozambique. The tree typically takes 60 years to mature.
Once felled the tree is cut into billets and the ends are sealed with wax ready to be sold and shipped around the world.
The wax slows the release of moisture ensuring that the wood does not split.
I try to buy pre-seasoned wood or part seasoned timber.
This wood is then left to season for as long as possible in the cooler climate of my storage shed.
The first stage of the wood turning is to turn the square billets into parallel round billets.
The wood is cut slightly over length and a pilot hole is bored into the billet.
This allows the air to get to the inside of the wood as well as the outside.
The wood is left to season between operations to allow the stress that has been in the timber to be relieved.
Heat is also generated in the machining process which can also cause cracking.
The wood is periodically checked for cracks and flaws.
The final turning takes place up to 3 to 6 months later.
The finished joints are then immersed in linseed oil and left.
Whilst the oil does not penetrate very deeply into the dense timber I feel it has a positive effect, reducing the possibility of cracking in the early period of the instruments life.
Final shaping takes place after the wood has been drained and the linseed oil wiped from the external surface.
After the final turning, the wood is yet again immersed in linseed oil and only extracted when the body is polished and set out ready to accept keywork.