Faults in Woods

Question	Answer
Cupping	When timber bends across the grain. Annual rings can be clearly seen on the end of the wood and the varying length of them means the wood dries at different speeds. This means the wood shrinks at different rates and cups.
Twisting	Can twist as it dries if the wood has come from the centre of a tree and has a spiral grain. Normally unusable.
Splitting	Where the grain separates at the end of a piece of wood - only thing to do is cut the affected ends off.
Knots	Natural by-product of where branches were attached to the tree. Can become loose and drop out if dead - which is very dangerous if the wood is being machined. Can be tight however, and even then are still a nuisance in terms of working the wood. Softwoods like pine tend to have many more knots.

Resource summary

	Created by Alec Stevens over 11 years ago