Civil Engineering Today

  Defects in timber   Defect occurring in timber are grouped into the following five categories: ·  Defects due to conversion ·  Defects due to fungi ·  Detects due to insects. ·  Defects due to natural forces. ·  Defects due to seasoning.   1. Defects due to Conversion - During the process of converting Timber to the commercial form, the following defects may occur: a. Chip Mark: This defect is indicated by the marks or signs placed by chips on the finished surface of timber. b. Diagonal Grain: Formed due to improper sawing of Timber. It is indicated by diagonal mark on straight grained surface of Timber. c. Torn Grain: In the conversion, many tools are used. If any of the tools or any other heavy things are dropped accidentally on the finished surface of timber it will cause small depression, which is called torn grain. OR    -   Small depression formed due to falling of a tree. d. Wane: This def...