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U. S. DEPARTMENT OF LABOR JAMES J. DAVIS, Secretary BUREAU OF LABOR STATISTICS ETHELBERT STEWART, Commissioner BULLETIN OF THE UNITED STATES > B U R EAU OF LABOR S T A T IS T IC S ) • • • • SAFETY CODE No. 338 SERIES SAFETY CODE FOR THE USE, CARE, AND PROTECTION OF ABRASIVE WHEELS INTERNATIONAL ASSOCIATION OF INDUSTRIAL ACCIDENT BOARDS AND COMMISSIONS AND GRINDING WHEEL MANUFACTURERS ASSOCIATION, SPONSORS TENTATIVE AMERICAN STANDARD Approved February 11, 1922, by American Engineering Standards Committee APRIL, 1923 WASHINGTON GOVERNMENT PRINTING OFFICE 1923 CONTENTS. Introduction......................... Section I. Scope and definitions................................................................................ Rule 10. Scope...................................................................................................... 11. Definitions............................................................................................. Section II. Types of protection devices.........„........................................................ Rule 20. General requirements........................................................................... Section III. Storage and inspection of wheels........................................................ Rule 30. Storage.................................................................................................. . 31. Inspection.............................................................................................. Section IV. General machine requirements............................................................. Rule 40. Rigidity, supports................................................................................ 41. Size of spindle....................................................................................... 42. Limit stop............................................................................................... 44. Direction of spindle thread................................................................. 45. Length of spindle thread..................................................................... 46. Size of wheel holes................................................................................ Section V. Protection hoods........................................................................................ Rule 50. General requirements......................................................................... 51. Mounting and fastenings.................................................................... 52. Exposure: Bench and floor stands.................................................... 53. Exposure: Cylindrical grindery........................................................ 54. Exposure: Surface grinders............................................................... 55. Exposure: Swing frame and portable grinders............................... 56. Exposure: Top grinding.................................................................... 57. Exposure adjustment......................................................................... 58. Fixed members.................................................................................... 59. Inclosure requirements................ .*................................................... 500. Dimensions for peripheral and sidemembers.................................. 501. Material specifications....................................................................... 502. Construction guide.............................................................................. 503. Connection requirements.................................................................. 504. Connecting members (specifications)............................................... 505. Dust exhaust provision...................................................................... Section VI. Work rests................................................................................................ Rule 60. Construction........................................................................................... 61. Adjustment........................................... ..........-................................... Section VII., Protection for cup, cylinder, and sectional ring wheels................. Rule 70. General requirements.......................................................................... 71. Hoods...................................................................................................... 72. Chucks.................................................................................................... 73. Bands...................................................................................................... Section VIII. Flanges.................................................................................................. Rule 80. General requirements.......................................................................... 81. Material.................................................................................................. 82. Finish and balance............................................................................... 83. Uniformity of diameter........................................................................ 84. Recess..................................................................................................... 85. F it........................................................................................................... 86. Straight flange dimensions.................................................................. 87. Protection flange requirements.......................................................... 88. Degree of taper...................................................................................... 89. Tapered flange dimensions................................................................. Section IX. Mounting.................................................................................................. Rule 90. Inspection............................................................................................. 91. F it........................................................................................................... 92. Surface condition.................................................................................. 93. Bushing.................................................................................................. 94. Washers................................................................................................... 95. Tightening of nut.................................................................................. hi Page. 1-3 3,4 3 3,4 4 4 5 5 5 5,6 5 5 5 5 6 6 6-12 6 6 6 6 6 7 7 7 7 7 8 9 9-11 11 11,12 12 12 12 12 13 13 13 13 13 13-16 13 13 14 14 14 14 14 15 15 15,16 16 16 16 16 16 16 16 IV CONTENTS. Page. Section X. Speed........................................................................................................... 17,18 Rule 100. Recommended and maximum speeds............................................. 17 101. Peripheral speed converted, to revolutions per minute................. 17 102. Speed test............................................................................................. 18 103. Speed adjustment control.................................................................. 18 Section XI. Operating rulesand general data.......................................................... 18 Rule 110. Responsibility...................................................................................... 18 111. Inspection after breakage.................................................................. 18 112. Replacing hood.................................................................................... 18 113. Starting new wheels............................................................................ 18 114. Applying work..................................................................................... 18 115. Test for balance................................................................................... 18 116. Truing................................................................................................... 18 18 117. Wet grinding............... 118. Side grinding........................................................................................ 18 119. Dresser guards...................................................................................... 18 1100. Grinding room...................................................................................... 18 1102. Lubrication.......................................................................................... 18 BULLETIN OF THE U. S. BUREAU OF LABOR STATISTICS WASHINGTON no . 338 april , 1923 SAFETY CODE FOR THE USE, CARE, AND PROTEC TION OF ABRASIVE WHEELS. INTRODUCTION. On April 3, 1920, the American Engineering Standards Committee invited the International Association of Industrial Accident Boards and Commissions and the Grinding Wheel Manufacturers Associa tion of the United States and Canada to act as joint sponsors for a safety code for the use, care, and protection of abrasive wheels. These associations both accepted this sponsorship, and according to the rules of procedure of the American Engineering Standards Committee they jointly appointed a sectional committee to draft such a code. This sectional committee consists of the following members: Name and address. Chairman, L. W. Chaney, U. S. Bureau of Labor Statistics, Washington, D. C. H. L. Whittemore, U. S. Bureau of Standards, Washington, I). C. Prof. E. A. Winslow, consulting hygien ist, 62 Park Street, New Haven, Conn. Fred G. Lange, Director of Safety In dustrial Commission of Ohio, Colum bus, Ohio. R. McA. Keown, Engineer, Industrial Commission of Wisconsin, Madison, Wis. John P. Meade, director, division of in dustrial safety, Department of Labor and Industry, Boston, Mass. Rowland H. Leveridge, bureau of elec trical and mechanical equipment. De partment of Labor, Trenton, N. J. J. C. Cronin, Department of Labor and Industry, Harrisburg, Pa. Secretary, A. Rousseau, safety engineer, Norton Co., Worcester, Mass. F. R. Henry, Dayton Grinding Wheel Co., Dayton, Ohio. George W. Chormann, Carborundum Co., Niagara Falls, N. Y. John R. Kempf, Detroit Star Grinding Wheel Co., Detroit, Mich. J. B. Baker, Safety Emery Wheel Co., Springfield, Ohio. J. H. Byers Abrasive Co., Philadelphia, Pa. H. W. Dunbar, member, A. S. M. E., Norton Co., Worcester, Mass. Association, society, or firm represented. Sectional committee group. U. S. Department of Labor......... Governmental bodies. U. S. Bureau of Standards.......... Do. U. S. Public Health Service........ Do. I. A. I. A. B. C. and Industrial Do. Commission of Ohio. I. A. I. A. B. C. and Industrial Do. Commission of Wisconsin. I. A. I- A. B. C. and Depart Do. ment of Labor and Industry of Massachusetts. I. A. I. A. B. C. and Depart Do. ment of Labor, New Jersey. I. A. I. A. B. C. and Depart Do. ment of Labor and Industry, Pennsylvania. Grinding Wheel Manufacturers Manufacturers of apparatus Association and Norton Co. concerned (grinding wheels and grinding machines). Grinding Wheel Manufacturers Do. Association and Dayton Grinding Wheel Co. Grinding Wheel Manufacturers Do. Association and Carborundum Co. Grinding Wheel Manufacturers Do. Association and Detroit Star Grinding Wheel Co. Grinding Wheel Manufacturers Do. Association and Safety Emery Wheel Co. Grinding Wheel Manufacturers Do. Association and Abrasive Co. National Machine Tool Builders Do. Association. 1 2 USE, CARE, AND PROTECTION OF ABRASIVE WHEELS. Name and address. C. HI Gale, superintendent foundries, Pressed Steel Car Co., McKees Rocks, Pa. G. E. Sanford, member A. I. E. E ., A. S. S.JE.and A. S.M .E ., General Elec tric Co., West Lynn, Mass. Gregory Brown, Norton Co., Worcester, F. M. Ward, Otis Elevator Co., Yonkers, N. Y. H. J. Weeks, chairman, General Stand ards Commission for State of Ohio, American Steel and Wire Co., Pitts burgh, Pa. B. C. Christy, International Harvester Co., Chicago, 111. S. E . Whiting.member, A. I. E . E ., Lib erty Mutual Insurance Co., Boston, Mass. L. L. Hall, Workmen’s Compensation Service Bureau, 13 Park Row, New York, N. Y. F. M. Rosseland, National Safety Coun cil. Chicago, 111. W. B. Gardiner, mechanical superin tendent, Lincoln Twist Drill Co., Taunton, Mass. A. J. Gifford, Leland-Gifford Co., Wor cester, Mass. G. E . Sanford, General Electric Co.,West Lynn, Mass. Rowland H . Leveridge, Department of Labor, Trenton, N. J. P . J. Conlon, 9th Street and Mt. Vernon Place NW ., Washington, D. C. George J. Speidel, 90 Bayway, Eliza beth, N. J. Association, society, or firm represented. Sectional committee group. American Foundrymen’s Asso Employers as users of grind ciation. ing wheels. National Founders’ Association.. Do. National Metal Trades Associa tion. Otis Elevator Co........................... American Steel and Wire C o.... International Harvester Co......... National Association Mutual Casualty Co. and Liberty Mutual Insurance Co. National Workmen’s Compen sation Service Bureau. National Safety Council............... American Society Mechanical Engineers. Society of Automotive Engi neers. American Society of Safety En gineers. ...d o .............................................. International Association of Ma chinists. Metal Polishers, Buffers and Platers of North America. Do. Do. Do. Insurance interests. General interests. Engineering and technical bodies. Do. Employees as users of equip ment. Do. Meetings of this committee were held, and as a result a code was drafted which was submitted first to the grinding-wheel manufac turers for approval. A few changes were suggested which were resubmitted to the sectional committee and to the International Association of Industrial Accident Boards and Commissions. This code in its present form is the net result of this work and was approved by the: International Association of Industrial Accident Boards and Com missions executive committee, November 18, 1921. Grinding Wheel Manufacturers Association, December 9, 1921. Sectional committee, by letter ballot, January 30, 1922. American Engineering Standards Committee, February 11, 1922. The membership of the two associations sponsoring this code is as follows: G r in d in g W h e e l M a n u f a c t u r e r s The Abrasive Co., Philadelphia, Pa. American Emery Wheel Works, Provi dence, It. I. Bridgeport Safety Emery Wheel Co., Bridgeport, Conn. Canadian-Hart Products Co., Hamilton, Ontario, Canada. Carborundum Co., Niagara Falls, N. Y. Chicago Wheel & Manufacturing Co., Chicago, 111. Cortland Grinding Wheels Corporation, Chester, Mass., and Cortland, N. Y. Dalton Grinding Wheel Co., Dayton, of U n it e d S t a t e s and Ca n a d a . Detroit-Star Grinding Wheel Co., Detroit, Mich. Dominion Abrasive Wheel Co. (Ltd.), New Toronto, Ontario, Canada. General Grinding Wheel Corporation, Philadelphia, Pa. Hampden Corundum Wheel Co., Springfield, Mass. Norton Co., Worcester, Mass. Norton Co. of Canada (Ltd.), Hamilton, Ontario, Canada. Pittsburg Grinding Wheel Co., Rochester, Pa. USE, CARE, AND PROTECTION OF ABRASIVE WHEELS. G r in d in g W h e e l M a n u f a c t u r e r s of U n it e d S t a t e s Precision Grinding Wheel Co., Phila delphia, Pa. Safety Emery Wheel Co., Springfield, Ohio. Sterling Grinding Wheel Co., Tiffin, Ohio. Superior Corundum Wheel Co., Walt ham, Mass. and C a n a d a —Concluded. Vitrified Wheel Co., Westfield, Mass. Waltham Grinding Wheel Co., Waltham, Mass. Waltham Grinding Wheel Co. of Canada (Ltd.), Brantford, Ontario, Canada. White Heat Products Co., Frazer, Pa. I n t e r n a t io n a l A sso c ia t io n of I n d u s t r ia l A c c id en t B o a r d s C o m m issio n s . ac tive m e m b e r s . U. S. Employees’ Compensation Com mission. U. S. Bureau of Labor Statistics. California Industrial Accident Commis sion. Connecticut Workmen’s Compensation Commission. Delaware Industrial Accident Board. Georgia Industrial Commission. Hawaii Industrial Accident Boards (coun ties of Kauai, Maui, Hawaii, and Hono lulu). Illinois Industrial Commission. Iowa Workmen’s Compensation Service. Kansas Court of Industrial Relations. Maine Industrial Accident Commission. Maryland State Industrial Accident Commission. Massachusetts Industrial Accident Board. Michigan Department of Labor and Industry. Minnesota Industrial Commission. Montana Industrial Accident Board. Nevada Industrial Commission. New Jersey Department of Labor. New York State Industrial Commission. Ohio Industrial Commission. Oklahoma Industrial Commission. Oregon State Industrial Accident Com mission. Pennsylvania Department of Labor and Industry. 3 and Utah Industrial Commission. Virginia Industrial Commission. Washington Department of Labor and Industries. West Virginia State compensation com missioner. Wisconsin Industrial Commission. Wyoming Workmen’s Compensation De partment. Department of Labor of Canada. Alberta Workmen’s Compensation Board. Manitoba Workmen’s Compensation Board. New Brunswick Workmen’s Compensa tion Board. Nova Scotia Workmen’s Compensation Board. Ontario Workmen’s Compensation Board. a sso c ia t e m e m b e r s . Idaho Industrial Accident Board. North Dakota Workmen’s Compensation Board. Ontario Safety League. Porto Rico Workmen’s Relief Commis sion. Republic Iron & Steel Company, Youngs town, Ohio. Industrial Accident Prevention Associa tion of Toronto. Nebraska Industrial Commission. SECTION I. SCOPE AND DEFINITIONS. 10. Scope.—This code is intended to give rules and specifications which are necessary to insure safety in the use of abrasive wheels operating at speeds in excess of 2,000 surface feet per minute. 11. Definitions. S h a l l a n d s h o u l d .—The word “ shall” where used is to be under stood as mandatory and “ should” as advisory. A b r a s i v e w h e e l .—The term “ abrasive wheel” where used shall be understood to mean power-driven wheels which consist of abrasive particles held together by artificial or natural mineral or organic bonds. Metal, wooden, cloth, or paper wheels or discs having a layer or layers of abrasive on the surface are not included. 4 USE, CARE, AND PROTECTION OF ABRASIVE WHEELS. P r o t e c t i o n h o o d . —A “ protection hood” is an inclosure consisting of a peripheral and two side members, constructed according to specifications which appear later in this code. C a s t h o o d .—A cast hood shall be defined as a hood which has the peripheral protecting member cast integral with at least one side member, and may be made of gray iron castings, malleable iron castings, or steel castings. F a b r i c a t e d h o o d . —A fabricated hood shall be defined as a hood which is built up or constructed by bolting, pinning, riveting, or welding the peripheral protecting member to the side members, and may be made of structural steel plate, wrought-iron plate, or an assembly of either of these in combination with gray iron castings, malleable iron castings, or steel castings or a material possessing an equivalent tensile strength. P r o t e c t i o n f l a n g e s . —“Protection flanges” are flanges designed to be used with abrasive wheels of special shape, in such a manner as to effectively retain the parts of a wheel—should such wheel break in operation—in addition to the usual function of clamping the wheel to the spindle. Protection flanges are of several types, of which the following are the most commonly used: “ Tapered flanges,” sometimes called safety, beveled, or concave flanges, which are used with wheels having convex side or sides. “ Hub flanges,” which are used with wheels having a raised hub or hubs. “ Ring flanges,” having concentric ring or rings projecting from the bearing sides of the flanges, which fit into corresponding grooves in the sides of the wheels. P r o t e c t i o n b a n d . —A “ protection band ” is a continuous band placed around a cup, cylinder, or sectional ring wheel to effectually retain the pieces of such a wheel which might break in operation. P r o t e c t i o n c h u c T c . —A “ protection chuck ” is a chuck used for mount ing cup, cylinder, or sectional ring wheels, so designed that the jaws inclose the wheel up to the point specified in rule 70. SECTION II. TYPES OF PROTECTION DEVICES. 20. General requirements.—All abrasive wheels shall be provided with one of the following forms of protection, which are listed in the order of preference: ( a ) Protection hoods. (b ) Protection flanges. (c ) Protection bands. ( d ) Protection chucks. Exception: This requirement shall not apply to wheels qsed for internal grinding, nor to wheels 3 inches or less in diameter running at a speed not exceeding 3,000 feet per minute. Forms x and d shall apply to cups, cylinders, and sectional ring wheels; forms a and b to all other shapes of wheels. USE, CARE, AND PROTECTION OE ABRASIVE WHEELS. 5 SECTION in. HANDLING AND STORAGE. 30. Storage.—Extreme care should be exercised in the storage of wheels. They should be stored in dry places and should be supported on edge in racks. Straight-sided shellac and rubber-bondea wheels of one-fourth inch or less in thickness shall be laid flat on a straight surface to prevent warpage. 31. Inspection.—Immediately upon receipt, all wheels should be closely inspected to make sure that they have not been injured in transit or otherwise. For added precaution wheels should be tapped gently with a light implement, such as the handle of a screw driver. If they sound cracked, they should not be used. Wheels must be dry, and free from sawdust, when applying the test. SECTION IV. GENERAL MACHINE REQUIREMENTS. 40. Rigidity, supports.—Grinding machines should be sufficiently heavy and rigid so as to minimize vibration. They should be securely mounted on substantial floors, benches, foundations, or other struc tures. 41. Size of spindle.—No user of wheels shall operate on any machine of given spindle diameter a wheel of larger diameter or greater thick ness than specified in the following table: Thickness of wheel in inches. Diameter in inches. 6........................... 7........................... 8........................... 9........................... 10......................... 12......................... 14......................... 16......................... 18......................... 20......................... 24......................... 26......................... 30......................... 36......................... % y2 5A K 1 m 2 2H 2Vz 2% 3 3H 3^ 4 5 y A y2 y y2 H y y y y y y y M y y 1 i i V2 y y H H Vs y y y y y y l i i 1 i i % % % H y H y y y i i i i l i i W iM y Vs H Vs y y y y i i i i i i y iy m H H y y y y y y i i i iy 1 Ya iy % M y y yi i i i i i m i M iM w i y m Vs Vs y$ % i i w iM iM W 2 w 2 iy iy iy iy iy i ^ i y iy i y i y i y i y iH m iy i M i H iJ i i y i y iy iy i y iy i y i y i y m m i X iy iy iy iy i y i y i y i y m m W s 2W s iy i y i y i y i y i y i y v y i y 2 2 2 2 i y iy i y i y i y 1H 2 2 2 2 2y 2M 2 « i y i y 2 2 2 2 2 2M 2M 2 y m 2y 2 2M 2M 2y zy %y2M 2 y 3 3 42. Limit stop.—Grinding machines should be provided with a stop or other means of fixing the maximum size of wheel which can be used. 44. Direction of spindle thread.—Ends of spindles shall be so threaded that the nuts on both ends will tend to tighten as the spindles revolve. Care should be taken in setting up machines that the spindles are arranged to revolve in the proper direction, else the nuts on the ends will loosen. N ote .—To remove the nuts they should both be turned in the direction that the spindle revolves when the wheel is in operation. 37543°—23—Bull. 338-----2 6 USE, CAKE, AND PROTECTION OF ABRASIVE WHEELS. 45. Length of spindle thread.—The length of the spindle and the distance from the end which the thread extends shall be such as to allow the entire length of the nut to bear on the thread so as to exert its full pressure on all thicknesses of wheels which may be used. 46. Size of wheel holes.—Wheel holes should be made approxi mately 0.005 inch large. SECTION V. PROTECTION HOODS. 50. General requirements.—Hoods should be used on every opera tion where the nature of the work will permit, and shall always be used with wheels which are not provided with protection flanges, chucks, or bands. 51. Mounting and fastenings.—Hoods shall be so mounted as to maintain proper alignment with wheels, and the fastenings shall have ample strength to minimize displacement in case of wheel breakage. 52. Exposure: Bench and floor stands.— The maximum angular exposure of the grinding wheel periphery and sides for hoods used on machines known as bench and floor stands should not exceed 90 or one-fourth of th e periphery. This ex posure snail begin at a p o in t n o t more than 65° above the F /£ / horizontal plane of the wheel spindle. (See fig. 1.) Wherever the nature of the work requires contact with the wheel below the horizontal plane of the spindle, the exposure shall not F /G .& exceed 125°. This exposure shall begin at a point.not more than 65° above and extend to a point not more than 60° below the horizontal plane of the wheel spindle. (See fig. 2.) 53. Exposure: Cylindrical grinders.—The maximum angular exposure of the grinding wheel periphery and sides for hoods used on cylindrical grinding ma chines shall not exceed 180°. This exposure shall begin at a point not more than 65° above the horizontal plane of *°°&ore the wheel spindle. (See F /& .3 fig. 3.) 54. Exposure: Surface grinders.—The maximnm angular exposure of the grinding wheel F /& 4 periphery and sides for hoods used on surface grinding machines which employ the wheel periphery shall not exceed 150°. (See fig. 4.) USE, CARE, AND PROTECTION OE ABRASIVE WHEELS. 7 55. Exposure: Swing frame and portable grinders.—The maximum angular exposure of the grinding wheel periphery and sides for hoods used on machines known as swing frame and portable grinding machines shall not ex ceed 180°, and the top , half of the wheel shall be protected at all times. (See fig. 5.) 56. Exposure: Top grinding.—In operations where the work is ground on the top of the wheel, the exposure of the grinding wheel pe riphery shall be as small as practicable, with a maximum exposure of 60°. (See fig. 6.) 57. Exposure adjustment.—Hoods shall be /^ /s .e constructed so that the peripheral protecting member can be adjusted to the constantly decreasing diameter of the wheel by means of an adjustable tongue, or its equivalent, so that the angular protection specified in rules 52 to 56 will be maintained througnout the life of the wheel, and the maximum distance between the wheel periphery and tongue or end of peripheral band at top of opening will not exceed inch. (See figs. 7, 8, and 9.) E /G . 8 - C O R R E C T . Showing adjustoh/e ton gi/e giving reg t/iret/o n g o /o r p rotection fo r a //s iz e s o f wheeis ucect. Showing m ovoh/e hooct with opening sm o /i enough £> give regoiredprotection fo r sm oi/est size w h ee/ u sed E /G . 9 -IN C O R R E C T . Showing m ovch/e t?ooctw it/? size o f opening correct for fu itsize w hee/, h u t too iorge fo r sm o //e r w heeif. 58. Fixed members.—Hoods shall be constructed so that it is not necessary when changing wheels to detach the peripheral protecting member from the side member which is connected to the machine. 59. Enclosure requirements.—The hood shall inclose the spindle end, nut, and flange projections, if any. N .—Protection hoods on cylindrical grinding machines, in all operations where the work provides a suitable measure of protection to the operator, may be so con structed that the spindle end, nut, and flanges are exposed; and where the nature of the work is such as to entirely cover the side of the wheel, the side covers of the guard may be omitted. ote 8 USE, CAKE, AND PROTECTION OF ABRASIVE WHEELS. 500. Minimum dimensions for the peripheral and side members. 9 USE, CAKE, AND PROTECTION OF ABRASIVE WHEELS. 501. Material specifications.—Materials used in the construction of hoods shall conform to and be in accordance with the following des ignated specifications of the American Society for Testing Materials: ( a ) Gray-iron castings—A 48. ( b ) Malleable-iron castings—A 47. ( c ) Steel castings—A 27 (class A). ( d ) Structural steel plate—A 9 (excluding specifications for rivet steel). ( e ) Wrought-iron plate—A 42 (class A). N o t e .—Copies of these specifications may be procured at a nominal price from the American Society for Testing Materials, Philadelphia, Pa. 502. Construction guide.—As a guide for the construction of fabricated hoods of steel plate or wrought iron the following drawings have been prepared. Other types offering equal protection will also be accepted. The requirements given in columns C, D, and E of this table shall apply also to cast hoods; and in such cases where the tongue is held by bolts, column F shall also apply. C Maximums^ace Diameter of tween wheel in new inches. wheel and hood at pe riphery in inches. Under 12.. i x 12 to 1 6 ... IX 17 to 24 . . . Over 24__ iIX x D E Maximum inside width of hood. Length of tongue in inches. 1 A inches wider 3X • than wheel. 2 inches wider 5 than wheel. ........do.................... 6 ........do.................... 7 F G Diam eter of bolts Size of angle supports for for tongue and rest tongue in inches. in inches. by V/2 by J^.. a 2 by 2 by A 2 by 2 by y . . X VA by 2A by y . . X H J Diam eter of rivets for sup ports in inches. Diam eter of end con necting bolts in inches. A A X X x A A X 10 USE, CARE, AND PROTECTION OF ABRASIVE WHEELS, F IG -. // F IG . fZ USE, CARE, AND PROTECTION OF ABRASIVE WHEELS, Z 11 Position opftonaf I lT Ac/jujfab/e Torque NOTE: D u s t e x h a u s t outlet should b e located In the p o s itio n where i t w ill most e ffe c tiv e ly remove the dust. For Suction Pipe sizes «see Pu/e SO S . F ig . 13. F R O N T V IEW ,A LS O C R O S S S E C T I O N S S H O W I N G F O U R S A T I S F A C T O R Y M E T H O D S OF SEC U R IN G C O Y E R ^ B S wore T.* h e se rto re : C o m b in e d v ie w s a ll a p p ly to ty p e s A ,B &C H o o d s s e c t io n a l o r e a o f a n g le s to o t le a s t e q u a l a r e a o t p e r ip h e r a l S EC T IO N tN T Q SH O W IN G AN GLE N U TS ON - ENDS BO LT- W E L D E D COVER Or H ELD BV BO LTS - S ECTIO N COVER FLA T SECTIO N IN TO G Y SH O W IN G B O L T A N G LE N UT^ S E C T I O N SH O W IN G IN TO GY AN GLE R tN S OF BY SID E V IEW W EDGE SH O W IN G H EYS THROUGH S T R A P S ~ THREADED O N LY - C O V E R ON END S AND H ELO IR O N H ELO B O L T S - STUO THREADED O N L Y - C O ^ £ ff H E L D THROUGH ENOS OF STUD S F IG . 14- P P O N T VICW 503. Connection requirements.—Hoods shall be constructed so that the connections between the peripheral and side members, or be tween parts of a sectional hood, will have a strength in a radial direc tion at least equal to the strength of the material of which the hoods are constructed. 504. Connecting members (specifications). 12 USE, CARE, AND PROTECTION OF ABRASIVE WHEELS. MINIMUM SIZES AND SPACING OF RIVETS, BOLTS, AND STUDS FOR CONNECTING PERIPHERAL AND SIDE MEMBERS IN FABRICATED HOODS OF WROUGHT-IRON AND STEEL PLATE. For side plate (B -l) at tached to machine. For detachable side plate (B-2). Thickness of plates being connected Maximum Diameter Maximum in inches. Diameter distance be of bolts or distance be of rivets tween centers tween centers in inches. in inches. in studs inches. in inches. Y and A ....... A and A...... A and {A ..... AY and and A...... y s ....... M and A ....... Vi and J*....... A and A..... A and ....... Vs and ....... % and A ....... A and M....... AY and A ....... and A ....... Y and % ....... V% and U and A ....... AAA Aa H H Vs Vs Vs Vs Vs Vs Vs Vs Vs Vs m iy 2 m 2 1% 2 2 2 iH m VY W2 A A AVs A Vs Vs A A AA A AA A % 3 3 3 3 4 SY 3 4 4 4 3Y 3 3 3 3 3 3 505. Dust-exhaust provision.—Hoods on machines used for dry grinding and other operations where dust is produced shall have provision made for connection to an exhaust system. The size of such connections shall be in conformity with the follow ing specified dimensions: Medium diameter Diameter of wheel. of branch pipe. 6 inches or less in diameter............................................................3 inches. 7 to 16 inches in diameter............................................................... 4 inches. 17 to 24 inches in diameter............................................................. 5 inches. 25 to 30 inches in diameter............................................................. 6 inches. A modification of the above requirements will be allowed in the case of narrow wheels used for light work where very little dust is generated and where a smaller pipe will satisfactorily remove it. The requirements m this paragraph shall not apply to swing-frame and portable grinding machines. SECTION VI. WORK RESTS. 60. Construction.—Work rests shall be rigid in construction. 61. Adjustment.—The work rest should be kept adjusted close to the wheel, with a maximum distance of Y inch, to prevent the work from being caught between the wheel and rest, and should be securely clamped after each adjustment. USE, CARE, AND PROTECTION OE ABRASIVE WHEELS. 13 SECTION VII. PROTECTION FOR CUP, CYLINDER, AND SECTIONAL RING WHEELS. 70. General requirements.—Cups, cylinders, and sectional ring wheels shall be either protected with hoods, inclosed in protection chucks, or surrounded with protection bands. Not more than onequarter of the height of such grinding wheels shall protrude beyond the provided protection. Where the thickness of the rim of such wheels is less than 2 inches, the maximum distance which the wheel may protrude beyond the provided protection shall not exceed 1 inch. If the thickness of the rim is 2 inches or more, the wheel m aj protrude 2 inches beyond the protection, but shall not exceed this amount. 71. Hoods.—Where hoods are used they shall conform to the specifi cations given in rules 50 to 505, inclusive, in this code. 72. Chucks.—Where the chuck which holds the wheel is the only protection provided, it shall be so designed that the jaws will at all times protect the wheel up to the point specified in rule 70. 73. Bands.—Where protection bands are used, they shall conform to the following specifications: ( a ) They shall be made of wrought-iron or steel plate or other material oi equal strength, shall be continuous and bent to conform as closely to tne periphery of the wheel as practical. The ends shall either be riveted, bolted, or welded together in such a manner as to leave the inside of the band free from projections. (b ) The bands shall be of sufficient width to provide the protection specified in rule 70. (c ) The thickness of the band shall be made according to the following table, which also shows the size and spacing for riveted joints. If bolting or welding is used, the strength of the connections shall be at least equal to the riveted joints specified in this table. MINIMUM THICKNESS, SIZE. AND SPACING OF RIVETS FOR PROTECTION BANDS FOR CUPS, CYLINDERS, AND SECTIONAL RING WHEELS. Size of wheels in inches. Under 8............................... 8 to 24................................. 25 to 30............................... Thickness Mirnmnmof of band in diameter rivets in inches. inches. A X X A X X Maximum distance between centers in inches. iX IX i SECTION VHI. FLANGES. 80. General requirements.—All wheels excepting those which are mounted in chucks shall always be run with flanges. 81. Material.—All tapered flanges over 10 inches in diameter shall be of steel, or other material of equal strength. All other flanges may be made of cast iron, or other material of equal strength. 14 USE, CARE, AND PROTECTION OF ABRASIVE WHEELS. 82. Finish and balance.—Flanges shall be finished all over correct to dimensions and in balance. The requirement for balance does not apply to so-called balancing flanges, which are purposely made out of balance. 83. Uniformity of diameter.—Both flanges, whether straight or tapered, in contact with wheel, shall be of the same diameter. 84. Recess.—Each flange, whether straight or tapered, shall be recessed at the center at least one-sixteenth of an inch on the side next to the wheel for a distance as specified in the respective tables of dimensions for straight and tapered flanges. 85. Fit.—The inner flange shall be keyed, screwed, shrunk, or pressed onto the spindle, and the bearing surface shall run true and at right angles with the spindle. The bore in the outer flange should be not more than 0.002 inch larger than the spindle. 86. Straight flange dimensions.—Where protection hoods are used, sizes of straight flanges for straight wheels shall not be less than shown in the following table: [All dimensions in inches.] A Diameter of wheel in inches. 1 2 3 4 5 6 8 10 12 14 16 18 20 22 24 26 28 30 36 c B Minimum outside diameter of flanges. l Minimum. Maximum. Vs X Vs Vs A H H X A yg A A 2 X X 3 3J* 4 X X Vs Vs A A 6 7 7A 8 10 10 *A 12 D Radial width of bearing surface. 1 Vs X X Vs Vs X X Vs Vs 1 u 1 in ix ix ix ix 2 E Minimum MioiTrmm thickness of thickness flange at of flange edge of at bore. recess. A X A A X Vs Vs Vs X X X Vs Vs Vs Vs Vs X X Vs A A A Vs Vs A A X A A A Vs Vs A A X X Vs X USE, CARE, AND PROTECTION OF ABRASIVE WHEELS. 15 87. Protection flange requirements.—Protection flanges (see defi nition) shall always be used with wheels 6 inches and larger which are not provided with protection hoods, chucks, or bands. (See rule 50.) Specifications follow for the tapered type only, which type should be used wherever possible. 88. Degree of taper.—Tapered protection flanges (see definition) shall always be used with tapered wheels having the same degree of taper, which should be at least % inch per foot tor each flange. 89. Tapered flange dimensions.—Where no hoods are used, the di mensions of taper flanges shall not be less than shown in the follow ing table: USE, CAKE, AND PROTECTION OF ABRASIVE WHEELS. 16 [All dimensions in inches.] A Diam eter of wheel in inches. 6 8 10 12 14 16 18 20 22 24 26 28 30 36 c B D E F thick Minimum thick ness of flange, ness at edge Maxi ofrecess. at bore. mum flat spot at For For For For center Maxi double single double single of mum. taper taper taper taper flange. wheels. wheels. wheels. wheels. Radial width of bearing surface. Mini mum outside diam eter of Mini flanges. mum. 3 4 5 6 8 14 16 18 20 22 24 28 hi l X l Vs X 10 12 X X A l Vs iM W* iX 2 23^ IX 3 Ws ix i% 2 2 Wi m m 4 4 Minimum X X Vs Vs x x Vs Vs % H X Vs % Vs 1 1 A X X A A Vs Vs x Ws X % % IX Ws A l Vs ix Ws X X X m A X X A Vs Vs Vs Vs A A A Vs Vs a X Vs 1 G Approxi mate diam eter of flat spot or hub of wheel. 0 0 0 1 1 2 4 4 4 4 4 4 4 4 4 4 4 4^ 4H 6 6 6 6 6 6 -6 6 6 N o t e .— Where hoods are used in conjunction with tapered wheels and tapered flanges, the specifications given in rule 86 may be followed. SECTION IX. MOUNTING. 90. Inspection.—Before mounting, all wheels should again be closely inspected to make sure that they have not been injured in transit, storage, or otherwise. (See rule 31.) 91. Fit.—Grinding wheels shall fit freely on the spindles; they should not be forced on, nor should they be too loose. (See rule 46.) 92. Surface condition.—All surfaces of wheels, washers, and flanges in contact with each other should be free from foreign material. 93. Bushing.—The soft metal bushing shall not extend beyond the sides of the wheel. 94. Washers.—Washers or flange facings of compressible material shall be fitted between the wheel and its flanges. If blotting paper is used, it should not be thicker than 0.025 inch. If rubber or leather is used, it should not be thicker than inch. If flanges with babbitt or lead facings are used, the thickness of the babbitt or lead should not exceed inch. The diameter of the washers shall not be smaller than the diameter of the flanges. 95. Tightening of nut.—When tightening spindle end nuts, care should be taken to tighten same only enough to hold the wheel firmly; otherwise the clamping strain is liable to damage the wheel or associated parts. USE, CARE, AND PROTECTION OF ABRASIVE WHEELS. 17 SECTION X. SPEED. 100. Recommended and maximum speeds.—The speeds shown in column A of the following table should not be exceeded, except on recommendation of the wheel manufacturer, and in no case should speeds shown in column B be exceeded. N o t e .—Some manufacturers are willing to recommend higher speeds for precision grinding and on rubber bonded wheels. Wheel classification. A Standard peripheral speed (feet per minute). B Maximum peripheral speed (feet per minute). 4,500 5,000 5.500 6.500 8,000 8,000 5,000 10,000 10,000 6,500 Vitrified and silicate wheels. Cup and cylinder wheels when used for rough grinding, on bench, floor, portable machines, etc.................................................................................................................... All other vitrified and silicate bonded wheels............................................................... Rubber and shellac bonded wheels. Rubber bonded wheels...................................................................................................... Shellac bonded wheels used for cutting off.................................................................. All other shellac bonded wheels....................................................................................... 101. Table of speeds. REVOLUTIONS PER MINUTE FOR VARIOUS SIZES OF GRINDING WHEELS TO GIVE PERIPHERAL SPEED IN FEET PER MINUTE AS INDICATED. Diameter of wheel in inches. 1 3 30.................. ..................................................... 32........................................................................ 34........................................................................ 36........................................................................ 4,000 s. f. m. 4,500 s. f. m. 5,000 s. f. m. 5,500 s. f. m. 6,000 s. f. m. 15,279 7,639 5,093 3,820 3,056 2,546 2,183 1,910 1,528 1,273 1,091 955 849 764 694 637 586 546 509 477 449 424 17,200 8,590 5,725 4,295 3,440 2,865 2,455 2,150 1,720 1,453 1,228 1,075 957 860 782 716 661 614 573 537 506 477 19,099 9,549 6,366 4,775 3,820 3,183 2,728 2,387 1,910 1,592 1,364 1,194 1,061 955 868 796 733 683 637 596 561 531 21,000 10,500 7,000 5,250 4,200 3,500 3,000 2,635 2,100 1,750 1,500 1,314 1,167 1,050 952 876 809 749 700 657 618 584 22,918 11,459 7,639 5,730 4,584 3,820 3,274 2,865 2,292 1,910 1,637 1,432 1,273 1,146 1,042 955 879 819 764 716 674 637 6,500 s. f. m. 24,850 12,420 8,270 6,205 4,970 4,140 3,550 3,100 2,485 2,070 1,773 1,552 1,380 1,241 1,128 1,035 955 887 827 776 730 689 N ote.—“ Centrifugal force, ” which is the force that tends to rupture a given wheel when overspeeding, increases as the square of the velocity of that wheel. For exam ple, the centrifugal force in a wheel running at 5,500 surface feet per minute is 49 per cent greater than in the same wheel running at 4,500 surface feet per minute, although the speed is actually only 22 per cent greater. 18 USE, CARE, AND PROTECTION OF ABRASIVE WHEELS. 102. Speed test. — Machine spindle speeds shall be tested and deter mined correct for size of wheel to be operated, before the wheel is mounted, and shall never be changed as wheel is reduced in diamater, except b y men assigned for such duties. — Where speed of wheel spindle is adjustable, speed adjustment shall be in control of authorized persons only. 103. Speed adjustment control. SECTION XL OPERATING RULES AND GENERAL DATA. 110. Responsibility.— Competent men should be assigned to the mounting, care, and inspection of grinding wheels and machines. 111. Inspection after breakage.— Whenever a wheel breaks, a careful inspection shall be made to make sure that the hood has not been damaged, nor the flanges bent or sprung out of true or out of balance. The spindle and nuts shall also be carefully inspected. — After mounting a new wheel, care should be taken to see that the hood is properly replaced. All new wheels shall be run at full operating speed for at least one minute before applying work, during which time the operator shall stand at one side. — Work should not be forced against a cold wheel, but applied gradually, giving the wheel an opportunity to warm and thereby minimize the chance of breakage. This applies to starting work m the morning in cold rooms, and to new wheels which have been stored in a cold place. — Wheels should be occasionally tested balance, and rebalanced if necessary. 112. Replacing hood. 113. Starting new wheels.— 114. Applying work. 115. Test for balance. for 116. Truing.—W heels worn out of round shall be trued by a competent man. Wheels out of balance through wear, which can not be balanced by truing or dressing, shall be removed from the machine. 117. Wet grinding wheels.— Wheels used in wet grinding should not be allowed to stand partly immersed in the water. The watersoaked portion may throw the wheel dangerously out of balance. A ll wet tool grinders which are not so designed as to provide constant supply of fresh water shall be thoroughly drained at the end of each day’s work and a fresh supply provided just before starting. — Grinding on the flat sides of straight wheels is often hazardous and should not be allowed on such operations when the sides of the wheel are appreciably worn thereby or when any considerable or sudden pressure is brought to bear against the sides. — Wheel dressers, excepting the diamond type, shall be equipped with guards over the tops of the cutters to protect the operator from flying pieces of broken cutters or wheel particles. — The space about the machine should be kept light, dry, and as free as possible from obstructions. — Care should be exercised so that the spindle will not become sufficiently heated to damage the wheel. a 118. Side grinding. 119. Dresser guards. 1100. Grinding room. 1102. Lubrication. INDEX Page. Abrasive wheel, definition................................. 3 Adjustment of work rest........................................ 12 Applying work, method of............................... 18 Balance and finish of flanges................................. 14 Balance, testing wheels for................................ 18 Bands, protection: Definition of......................................... 4 Specifications for...................................... -. 13 Bench and floor stands, exposure allowed___ 6 Blotters..................................................................... 16 Breakages, wheel, inspection after...................... 18 Bushings, general requirements........................... 16 Cast hood: Definition...................................................... 4 Specifications. (See Hoods.) Castings, specifications for................................. 9 Chucks, protection: Definition of.................................................. 4 Specifications for.......................................... 13 Compressible washers......................................... 16 Connecting members of hoods, specifications for........................................................................ 12 Connection requirements for hoods................. 11 Construction guide for hoods............................. 9 Control of speed adjustment............................. 18 Cracked wheels, inspection for......................... 5,16 Cup wheels, protection for................................. 13 Cylinder wheels, protection for........................ 13 Cylindrical grinders, exposure allowed........... 6 Definitions............................................................ 3,4 Degree of taper for protection flanges.............. 15 Dimensions. (See article in question.) Direction of rotation........................................... 5 Direction of spindle thread............................... 5 Dresser guara....................................................... 18 Dry grinding, dust exhaust provisions........... 12 Dust exhaust provisions.................................... 12 Enclosure requirements..................................... 7 Exhaust, dust, provisions for........................... 12 Exposure adjustment......................................... 7 Exposure allowable: Bench and floor stands............................... 6 Cylindrical grinders..................................... 6 Surface grinders............................................ 6 Swin g frame and portable.......................... 7 Top grinding................................................. 7 Fabricated hood: Definition...................................................... 4 Specifications. (See Hoods.) Fastenings and mounting for hoods................ 6 i inish and balance of flanges............................ 14 Fit of flanges........................................................ 14 Fit of wheel.......................................................... 16 Flange facings...................................................... 16 Flanges, general requirements.......................... 13 Flanges, protection: Definition of.................................................. 4 Specifications for............................................ 14-16 Flanges, straight, specifications for.................. 14 Flanges, tapered, specifications for.................. 15 Floor and bench stands, exposure allowed... 6 Grinding room, general conditions.................. 18 Handling and storage, precautions.................. 5 Holes in flanges, size of...................................... 14 Holes in wheels, size of....................................... 6 Hoods, protection: Page. Connecting members, specifications......... 11,12 Connection requirements............................ 11 Construction guide—fabricated hoods__ 9 Definition....................................................... 4 Dimensions for peripheral and side mem bers.............................................................. 8 D ust exhaust provision................................. 12 7 Enclosure requirements.............................. Exposure adjustment.................................. 7 Exposure for bench and floor stands....... 6 Exposure for cylindrical grinders............. 6 Exposure for surface grinders.................... 6 Exposure for swing frame grinders........... 7 Exposure for top grinding.......................... 7 Fixed members............................................. 7 General requirements.................................. 6 Material specifications................................. 9 Mounting and fastenings............................ 6 Hoods, replacing after mounting wheel......... 18 Hub flanges, definition....................................... 4 Inspection of equipment after wheel break ages..................................................................... 18 Inspection of wheels before mounting............. 16 5 Inspection of wheels on receipt........................ Internal grinding, exception to protection requirements..................................................... 4 Lead-faced flanges............................................... 16 6 Length of spindle thread................................... Lighting conditions in grinding room............. 18 Limit stop for size of wheel............................... 5 Lubrication of machine...................................... 18 Machine: Direction of spindle thread........................ 5 General requirements.................................. 5 Length of spindle thread............................ 6 Limit stop...................................................... 5 Rigidity, supports, etc................................ 5 Spindle size.................................................... 5 Wheel hole size............................................. 6 Material for flanges, specifications.................... 13 Material for hoods, specifications...................... 9 Mounting of hoods............................................... 6 Mounting of wheels............................................. 16 Nut, spindle end, tightening of........................ 16 Opening in hoods, size of................................... 6,7 Peripheral member for hoods, dimensions— 8 Portable and swing frame grinders, exposure allowed............................................................... 7 Protection bands. (See Bands.) Protection chucks. (See Chucks.) Protection devices, general requirements___ 4 Protection flanges. (See Flanges.) Protection hoods. (See Hoods.) Recess in flanges.................................................. 14 Recommended and maximum speeds............ 17 Responsibility for care, etc................................ 18 Rests, work.......................................................... 12 Revolutions per minute and surface speeds.. 17 5 Rigidity ofsupports............................................ 4 Ring flanges, definition...................................... Ring wheels, sectional, protection for............. 13 5 Rotation, direction of......................................... 3 Scope of code........................................................ Sectional ring wheels, protection for............... 13 Side grinding restriction.................................... 18 19 20 INDEX, Tapered flanges: Page. Degree of taper...................... 15 Dimensions............................. 15 General requirements........... 15 Test: Balance................................... 18 Speed....................................... 17,18 Thread, spindle: 5 Direction of............................ Length of................................ 6 Tightening of nut......................... 16 Top grinding, exposure allowed. 7 Truing of wheel............................ 18 Washers, compressible........................................ 16 Wet grinding, provisions for............................. 18 Page. Side members of hoods, dimensions................ 8 Size. (See article in question.) Speed adjustment control.................................. 18 Speed in revolutions per minute and surface feet per minute................................................. 17 Speed test.............................................................. 17,18 Speeds, recommended and maximum............ 17 Spindle sizes.......................................................... 5 Spindle thread: Direction of................................................... 5 Length of....................................................... 6 Starting new wheels, test before...................... 18 Storage of wheels................................................. 5 Straight flanges, dimensions............................. 14 Supports, rigidity of........................................... 5 Surface grinders, exposure allowed................. 6 Swing frame grinders, exposure allowed........ 7 ADDITIONAL COPIES OF THIS PUBLICATION MAY BE PROCURED FROM THE SUPERINTENDENT OF DOCUMENTS GOVERNMENT PRINTING OFFICE WASHINGTON, D. C. AT 5 CENTS PER COPY PURCHASER AGREES NOT TO RESELL OR DISTRIBUTE THIS COPY FOR PROFIT.— PUB. RES. 57, APPROVED MAY 11, 1922 V