Machinery's Handbook, 31st Edition
1328 SURFACE GRINDING Operating Surface, Face of Wheel: Movement of Work, Traverse Along Straight or Arcu ate Path: The grinding wheel, usually of segmental type, is set in a position to cover either an annular area near the periphery of the table or, more commonly, to reach beyond the table center. A large circular magnetic chuck generally covers the entire table surface and facilitates the mounting of workpieces, even of fixtures, when needed. The uninterrupted passage of the work in contact with the large wheel face permits a very high rate of stock removal and the machine, with single or double wheelhead, can be adapted also to auto matic operation with continuous part feed by mechanized work handling. Selection of Grinding Wheels for Surface Grinding.— The most practical way to select a grinding wheel for surface grinding is to base the selection on the work material. Table 2a gives the grinding wheel recommendations for Types 1, 5, and 7 straight wheels used on reciprocating and rotary table surface grinders with horizontal spindles. Table 2b gives the grinding wheel recommendations for Type 2 cylinder wheels, Type 6 cup wheels, and wheel segments used on vertical spindle surface grinders. The last letters (two or three) that may follow the bond designation V (vitrified) or B (resinoid) refer to: 1) bond modification, “BE” being especially suitable for surface grind - ing; 2) special structure, “P” type being distinctively porous; and 3) for segments made of 23A type abrasives, the term 12VSM implies porous structure, and the letter “P” is not needed. The wheel markings in Table 2a and Table 2b are those used by the Norton Co., complementing the basic standard markings with Norton symbols. The complementary symbols used in these tables, that is, those preceding the letter designating A (aluminum oxide) or C (silicon carbide), indicate the special type of basic abrasive that has the friability best suited for particular work materials. Those preceding A (aluminum oxide) are 57—a versatile abrasive suitable for grinding steel in either a hard or soft state. 38—the most friable abrasive. 32—the abrasive suited for tool steel grinding. Those preceding C (silicon carbide) are 37—a general application abrasive, and 39—an abrasive for grinding hard cemented carbide. Table 2a. Grinding Wheel Recommendations for Surface Grinding— Using Straight Wheel Types 1, 5, and 7 23—an abrasive with intermediate grinding action, and 19—the abrasive produced for less heat-sensitive steels.
Horizontal-spindle, reciprocating-table surface grinders
Horizontal-spindle, rotary-table surface grinders
Wheels less than 16 inches diameter 37C36-K8V or 23A46-I8VBE 37C36-K8V 23A46-J8VBE 32A46-H8VBE or 32A60-F12VBEP 32A46-I8VBE 23A46-H8VBE Diamond wheels a
Wheels 16 inches diameter and over 23A36-I8VBE 37C36-K8V 23A36-J8VBE 32A36-H8VBE or 32A36-F12VBEP 32A36-J8VBE 23A36-I8VBE Diamond wheels a
Material
Wheels of any diameter
37C36-K8V or 23A46-I8VBE 37C36-K8V 23A46-J8VBE 32A46-I8VBE 32A46-J8VBE 23A46-I8VBE
Cast iron
Nonferrous metal
Soft steel
Hardened steel, broad contact Hardened steel, narrow contact or interrupted cut General-purpose wheel Cemented carbides
Diamond wheels a a General diamond wheel recommendations are listed in Table 5 on page 1309.
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online