American Machinist Grinding Book: Modern Machines and Appliances, Methods and Results

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McGraw-Hill Book Company, 1912 - Grinding and polishing - 383 pages
 

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Page 118 - The intermediate letters between those designated as soft, medium soft, etc., indicate so many degrees harder or softer; eg, L is one grade or degree softer than medium; O, two degrees harder than medium, but not quite medium hard.
Page 54 - The limits given In the table can be recommended for use In the manufacture of machine parts to produce satisfactory commercial work. These limits should be followed under ordinary conditions. Special cases should always be considered, as It may be desirable to vary slightly from the table*.
Page 178 - Never mount a wheel without flanges which are properly relieved and of suitable proportions. For details of flanges and methods of mounting various types of wheels see the preceding chapter. Do not screw up the nut too tight; it should be set up only enough so that the flanges hold the wheel firmly. Keep all rests adjusted close to the wheel so that work cannot be caught. Avoid heavy pressure of the work 011 the wheel when grinding.
Page 42 - In all cases, accurate turning increases the total cost of production and in some it makes the grinding very expensive. The greatest economy is usually obtained by the combination of grinding with very rough turning. Yet there are cases where the least expensive way is to grind direct without turning, notably the greater part of crankshafts of automobiles and small gas engines and very long and slender work where turning is difficult.
Page 176 - Rule.— Multiply the number of revolutions per minute of the grinding spindle by the diameter of its pulley, and divide the product by the number of revolutions per minute of the countershaft. Example. — The...
Page 117 - The rubber or vulcanite bond has the general characteristics of the clastic, but its grades of hardness cannot be varied to the same extent and its uses are limited." GRAIN AND GRADE Grinding wheels are made in various combinations of coarseness and hardness to meet the variety of conditions under which they are used. The cutting material is crushed and graded from coarse to fine in many sizes designated by number. Thus the sizes of grain used in the Norton wheels are numbered 10, 12, 14, 16, 20,...
Page 57 - ... both soft and hard. A reversal of the usual rule where economy is gained by having one man operate more than one machine is shown in Example 6, where work is...
Page 176 - Rule. — Multiply the number of revolutions per minute of the countershaft by the diameter of the tight and loose pulleys and divide the product by the number of revolutions per minute of the lineshaft.
Page 57 - Nos. 1 to 6 show some samples of commercial grinding taken from actual practice for the purpose of giving an idea of what can be done in a commercial way, as well as to give some definite data as to speeds, feeds, etc. While it is perhaps not possible to give a rule that will fit all work, these...
Page 44 - Five bearings, all round within 0.00025 in.; the axis of all parallel and exactly in line; all of the right length within 0.004 in.; distance between bearings within 0.004 in. ; accumulated error not over 0.008 in. Four crank pins, all round within 0.00025 in.; the axis of all exactly parallel; all to length within 0.004 in.; all parallel with the bearings; all within 0.005 in. of the same plane; all of correct throw, within 0.010 in.; overall length, accumulated error not over 0.008 in. ; all fillets...

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