How many types of timber defects are there?
The defects occurring in the timber are grouped into the following five divisions: (1) Defects due to Conversion (2) Defects due to Fungi (3) Defects due to Insects (4) Defects due to Natural Forces (5) Defects due to Seasoning.
The various types of defects under each category will now be briefly discussed..
What are the natural defects in wood?
Natural Wood Defects. During its lifetime, a tree is subjected to many natural forces that cause defects in the wood. Woodworkers are quite familiar with these defects – knots, splits, ugly dark streaks or stains, worm holes, even decay.
What are defects and blemishes in wood?
A defect in lumber is any flaw that tends to affect the strength, durability, or utility value of the lumber. A blemish is a flaw that mars only the appearance of lumber.
What does checking of wood mean?
Due to the innate characteristics of wood, it shrinks and swells differently. This is best explained in the image below. … A check is separation in wood fibers across the annual rings of a piece of wood and a split is a separation of wood fibers across the annual rings but through a piece wood.
Why is wood dust dangerous?
Wood dust is also associated with toxic effects, irritation of the eyes, nose and throat, dermatitis, and respiratory system effects which include decreased lung capacity and allergic reactions. … Wood dust is also a safety concern because it can cause a fire or explosion.
What is the cause for twisting defect in timber?
Twist: Twist in timber rotates the ends of the timber in opposite directions. The main reason behind this defect is twisting of the trees by the strong wind. … The main reasons behind star shakes are extreme heat or frosting during the growth of the trees and rapid or uneven seasoning after cutting off the timber.
What are the artificial defects in timber?
Secondary (Artificial) Defects of Timber.CHECKS. These are cracks or clefts developing longitudinally in the logs after their felling. These cracks or checks are often cutting across the annual rings of the log. … WARPS. Warping is defined as a deformation in the original plane surface of a board cut from the timber.
What are the defects of wood?
The following are a list of the most common wood defects.Bow (Bowing) The curvature of a piece of sawn timber in the direction of its length, cf. … Boxed Heart. … Checks. … Compression Fanures. … Cup (Cupping) … Diamond (Diamonding) … Honeycomb. … Split (also known as a Shake)More items…