Synopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt: ...8 =.7198. Multiply by number of teeth, 10 = 7.198. Add two pitches, or.25, gives 7.448 as outside diameter. The lead of spiral is 3.1901. Dividing by pitch, 8 =.3988. Multiplying by number of teeth = 3.988 the lead of spiral. When racks are to mesh with spiral gears, divide the number in the circular pitch columns for the given angle by the required diametral pitch to get the corresponding circular pitch. If we want to make a rack to mesh with a 40-degree spiral gear of 8 pitch: Look for circular pitch opposite 40 and find 4.101. Dividing by 8 gives.512 as the circular pitch for this angle. The greater the angle the greater the circular or linear pitch, as can be seen by trying an 80-degree angle. Here the circular pitch is 2.261 inches. SECTION VII GRINDING CHAPTER I TYPES OF GRINDING MACHINES Grinding machines as commonly used in manufacture may be grouped under the following classifications: (1) Machines for grinding cylindrical and conical surfaces, both external and internal. (2) Machines for grinding plane surfaces. (3) Cutter, tool and drill grinders for keeping in order milling cutters and reamers, lathe and planer tools, and twist drills. These are ordinarily sharpening machines and not for sizing work. In certain designs, however, the functions of cylindrical and surface grinders are combined with those of the cutter, reamer and tool grinder. (4) Center and portable grinders for use in the tool post. (5) Bench, floor and swing frame grinders for general shop and foundry purposes, also for polishing and buffing. GROUP 1 MACHINES FOR GRINDING CYLINDRICAL AND CONICAL SURFACES In group 1, we have the following types of machines: (a) Plain grinders, especially adapted for manufacturing purposes such as the grinding of rolls and shafts, machine spindles...
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