End grain
As grain wood or forehead wood are in wood is transverse to the longitudinal axis ( machine direction ) denoted cut surfaces that the annual rings as circles or segments of circles show. A saw cut at an angle of 90 ° to the grain is called a brain or cross section.
Since the brain cut exposes all the capillaries of the wood, liquids can penetrate more easily than with longitudinal wood . A significantly larger application quantity is required to impregnate end grain.
use
End grain surfaces are more resilient to pressure than surfaces cut parallel to the fibers (longitudinal wood surfaces) . When laying wooden paving , the end grain surfaces point upwards (perpendicular to the load). End grain was used in rain-protected driveways instead of natural stone paving (for example in the southern entrance to the courtyard of the Weimar City Palace and behind the front gate of the grand ducal palace in Luxembourg City). Wooden pavement muffles the noise of the horse-drawn carriage wheels.
Even chopping blocks are now mostly glued wooden blocks, have their grain surfaces upwards. Sharp blades penetrate between the fibers of the surface of the front wood, but do less damage to the front wood surface than longitudinal wood surfaces, the fibers of which they cut through and loosen over time.
Wood is an anisotropic material that has a higher tensile strength in the longitudinal direction than it is across the grain. In the case of highly stressed wood connections , no screws or nails should be driven into the end faces. The pull-out strength of screws and nails in end-grain wood is low because it splits easily and the shaft is held in place by a smaller number of fibers that are also easier to detach from the composite. The pull-out strength can be increased by driving nails or screws into the end grain at an angle. In the case of nails, the direction is changed alternately.
In the fine arts , wood engraving , which was developed by Thomas Bewick in England in the 18th century in analogy to copper engraving , was the most important means of reproducing drawings until the invention of photo-technical reproduction processes. Most end-grain wood (of the boxwood ) was used because of its hardness and density. In the older woodcut , longitudinal wood was used for the printing block.
Individual evidence
- ↑ Wolfgang Nutsch and others: expertise for carpenters (12th edition), published by Europe teaching aids, Wuppertal 1980, page 33, ISBN 3-8085-4011-7
- ↑ How to nail nails correctly - #Handwerkerwissen , In: Hornbach.de; accessed in February 2020