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Hand tools Metalworking
Woodworking Moretofollow |
Wood finishing is the process of removing all tool marks from the wood by the means of a cabinet scraper and sandpaper, and applying a protective coating to the surface. In most cases, the scraping and sandpapering of the work can be done after it is assembled; but surfaces that would be difficult to work on after assembly, such as the inside of a drawer, should be finished before assembly. ScrapingIn woodworking scraping is the process of smoothing a wood surface by removing material in very thin shavings. A cabinet scraper is generally used for this purpose. Scraping may follow coarse planing, to remove irregularities left by the plane. When a surface has changes in grain direction, scraping should replace planing, which would tear or split the wood fibers. Veneers which are no more than 1/28" in thickness should never be planed on the surface, as this removes too much of the material. The scraper should be used, for the shaving produced by this tool is considerably thinner than that produced by the plane. The refinishing of flat surfaces of furniture can best be done by scraping. After the greater part of the old finish has been removed with a varnish remover, the cabinet scraper is used to complete the work of preparing the surfaces for the new finish. SandingSanding is the process of removing all tool marks or other irregularities to produce a smooth even surface on the wood. Sandpaper is generally used for this purpose. Sandpaper is a coated abrasive made of finely ground flint quartz or garnet crystals cemented to heavy paper or cloth. Flint-quartz paper can be obtained in grades ranging from No. 3 1/2 to No. 5/0; garnet paper is made in grades from No. 4 1/2 to No. 10/0. The grading of the abrasive is based on the size of the crystals; No. 4 1/2 is the coarsest, and No. 10/0 is the finest. The first sanding should be done with #1 to #1/2 sandpaper, depending on the amount of wood that must be removed to eliminate tool marks. This is followed by the use of a #0 or 2/0 sandpaper. Sandpaper is made in rolls and in 9" X 11" sheets. It can be cut by folding it over a sharp corner of the bench and tearing it along the fold line; under no condition should any cutting tool be used to cut sandpaper. The most convenient size for a piece of sandpaper is 4 1/2" X 5 1/2", which can be obtained by cutting a full-size sheet into four parts. For sanding, the sandpaper must be stretched over a block. The block should be 3" wide, 4" long, and at least 3/4" thick. It should be made of cork or of wood with a thin layer of cork glued to one face. The purpose of the block is to prevent the rounding of corners or the cutting of grooves in the surface of the work being sanded. The stock to be sandpapered should be held securely
in the vise or to the bench top by means of a hand screw. The sandpaper
block is grasped in both hands, with the fingers on one edge and the thumbs
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