Machine Shop Work and Management; A Comprehensive Guide to the Most Approved Methods in Modern Shop Practice, Including the Construction and Use of Improved Tools and Machines, and Other Details of Shop Equipment and Management (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 edition. Excerpt: ...A coarse wheel grinds faster than a fine one, but leaves deep scratches in the work. A soft wheel may be made of a much finer grade of emery than a hard one. A soft wheel grinds faster than a hard one, but it is apt to glaze over, or fill up with particles, if used on a soft material. Lubrication. To increase the cutting capacity of an emery wheel, to prevent it from glazing over, and to carry off the heat generated by the friction of the wheel on the work, a stream of water is frequently used, arrangements being made in most machines--particularly in those for grinding tools and for cylindrical grindingfor forcing the stream upon the wheel at the point of contact with the work, by means of a small pump.' For grinding milling cutters, reamers, taps, and similar tools, water is not used.. Table II gives the maximum speeds of carborundum wheels of various diameters. The accuracy of grinding renders the use of fine measuring tools a necessity. The micrometer caliper, especially with the vernier graduation, is best suited for this work. While grinding is the only method of finishing some materials, such as hardened tool steel, and the most accurate way of finishing any kind of stock, its value as an economical method is just beginning to be recognized. The general method of finishing lathe woik has been to take a roughing cut with about T', inch feed, then a finishing cut with about flq inch feed, and then file to remove the tool marks. In the majority of cases it is more economical, as well as more accurate, to take a roughing cut with % inch feed to within 151; inch of the size, and then finish by grinding. In some cases it is possible to get excellent results by grinding to size directly from the bar without previous turning. Lapping...