To get timber or flat boards you have to cut a round log. And to do so there are several methods to get the most of it on its grain appearance, best quality of timber or to get the best yield. Using bandsaw is quite common at larger sawmills, and smaller sawmill or logs normally using circle saw.
Some manufacturers prefer to buy sawn timber (dried or not dried), or not invest a sawmill facility in their factory. But larger manufacturers normally will install sawmill in-house for them to have better control on their yield and material cost and to have timber dimension just as they need.
There are mainly 3 ways to cut logs:
Plain Sawn
The most commonly used by sawmills and the best yield can be achieved. It is the most efficient way and works for any shape of logs (round or oval). The cutting is just one or two direction along the log from one end to another. And it can be done by a vertical or horizontal bandsaw machine.
The timber grain mostly from tangential side, less straight and more curvy (U-shape) and the wood shrinkage is bigger on its width side.
Quarter Sawn
This method produces less yield and less efficient. The log is sawn into 4 quarter in the middle, and cut into boards several ways along the logs (see the figure). The grain appearance is a mix between radial and tangential. You can have more straight grain timber using this method.
Rift Sawn
The least yield and the most inefficient sawing method. It produce a lot of waste but the quality of the timber is the best among other methods. Riftsawn cutting angle are mostly around 40-60 degree direction, aiming only radial cuts. It results straight grain timber and very low wood shrinkage ratio.
Some people find straight grain more attractive. And as it is less efficient, it becomes more expensive compared to timber with curvy (U-shape) grain.
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