Safety Requirements forUse, Care and Protectionof Abrasive Wheels

AN

SI B

7.1-

2000

ANSI B7.1-2000Revision of B7.1-1995

SPONSOR

Unified Abrasives Manufacturers’ AssociationDEVELOPER

Bonded DivisionApproved April 27, 2000

i

ANSIB7.1-2000

Revision ofANSI B7.1-1995

American National Standard

Safety Requirements forthe Use, Care and Protection

of Abrasive Wheels

Secretariat

Unified Abrasive Manufacturers’ Association

Approved April 27, 2000

American National Standard

ii

Approval of an American National Standard requires verification by ANSlthat the requirements for due process, consensus, and other criteria forapproval have been met by the standards developer.

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The American National Standards Institute does not develop standards andwill in no circumstances give any interpretation of any American NationalStandard. Moreover, no person shall have the right or authority to issue aninterpretation of an American National Standard in the name of the Ameri-can National Standards Institute. Requests for interpretations should beaddressed to the secretariat or sponsor whose name appears on the titlepage of this standard.

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AmericanNationalStandard

Published by

Unified Abrasive Manufacturers’ Association30200 Detroit Road, Cleveland, Ohio 44145-1967

Copyright © 2000 by American National Standards Institute.All rights reserved.

No part of this publication may be reproduced in anyform, in an electronic retrieval system or otherwise,without prior written permission of the publisher.

Printed in the United States of America

ANSI B7.1-2000

i

PageContents

Foreword ............................................................................................................ ix

1 Scope and definitions ......................................................................................1

1.1 Scope......................................................................................................1

1.2 Definitions ...............................................................................................1

1.3 Usage definitions ..................................................................................12

1.4 Definitions and limitations of wheel shapes ..........................................16

1.4.1 Abrasive disc wheels ...................................................................16

1.4.2 Corner clearance (‘C’ dimension) ................................................17

1.4.3 Recess diameter (‘P’ dimension) ................................................. 17

1.4.4 Type 1 straight wheels................................................................. 17

1.4.5 Type 2 cylinder wheels ................................................................18

1.4.6 Type 5 recessed one side wheels ............................................... 18

1.4.7 Type 6 straight cup wheels .......................................................... 18

1.4.8 Type 7 double recessed wheels ..................................................19

1.4.9 Type 11 flaring cup wheels .......................................................... 19

1.4.10 Type 12 dish wheels ..................................................................20

1.4.11 Type 13 saucer wheels ..............................................................20

1.4.12 Types 16, 17, 18, 18R and 19 cone and plug wheels ............... 21

1.4.13 Types 20, 21, 22, 23, 24, 25, 26 relieved and/or recessed wheels ............................................................22

1.4.14 Types 27 and 28 depressed center wheels ............................... 22

1.4.15 Type 27 abrasive flap disc wheels............................................. 23

1.4.16 Type 27A depressed center wheels ..........................................23

1.4.17 Type 29 wheels .........................................................................23

1.4.18 Cutting-off wheels ......................................................................24

1.4.19 Mounted wheels ........................................................................ 25

1.4.20 Threaded hole cup wheels ........................................................ 25

1.4.21 Tuck pointing wheels ................................................................. 25

1.4.22 Modified Types 6 and 11 wheels (terrazzo) ............................... 26

1.5 Abrasive wheels for use on portable air grinding machines.................. 26

2 Handling and storage ....................................................................................27

2.1 Acceptance of shipment........................................................................ 27

2.2 Handling................................................................................................27

2.3 Storage .................................................................................................27

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3 General machine conditions.......................................................................... 31

3.1 Grinding machine design and maintenance .........................................31

3.1.1 Supplier's responsibility ............................................................... 31

3.1.2 Owner's responsibility ................................................................. 31

3.1.3 Operator's responsibility ..............................................................31

3.2 Safety guards........................................................................................ 31

3.3 Spindle ..................................................................................................32

3.3.1 Diameter of spindle .....................................................................32

3.3.2 Tolerance of spindle or mount, up to 3 inches ............................. 32

3.3.3 Tolerance of spindle or mount, 3inches and larger .................... 32

3.3.4 Length of machine spindle thread ............................................... 33

3.4 Direction of machine spindle rotation.................................................... 33

3.4.1 Direction of machine spindle thread ............................................33

3.4.2 Direction arrows .......................................................................... 33

3.4.3 Machines using threaded hole wheels ........................................ 35

3.5 Flanges ................................................................................................. 35

3.6 Diameter and speed control for grinding machines ..............................35

3.7 Work support on stationary and bench grinders ...................................36

3.7.1 Work support for off-hand grinding ..............................................37

3.7.2 Work support for cylindrical grinding machines ........................... 37

3.7.3 Auxiliary work support for cylindrical grinding machines ............. 37

3.8 Portable grinding machines ..................................................................37

3.8.1 Spindles ......................................................................................38

3.8.2 Flange design ..............................................................................38

3.8.3 Side handles ............................................................................... 39

3.9 Mount design for abrasive discs ...........................................................39

3.10 Mount design for plate mounted type discs ........................................ 41

3.11 Stationary machines, excluding bench and pedestal grinders ............42

3.11.1 Power ........................................................................................ 42

3.11.2 Exhaust provision ...................................................................... 42

3.11.3 Moving parts ..............................................................................42

3.11.3.3 Power transmission .....................................................42

3.11.4 Grinding tools ............................................................................43

3.11.4.1 Honing tools ................................................................. 43

3.11.5 Sharp corners and edges .......................................................... 43

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3.11.6 Direction of controls ...................................................................43

3.11.6.1 Lever controls ..............................................................44

3.11.6.2 Push button controls ....................................................44

3.11.6.3 Hand wheel controls ....................................................45

3.11.6.4 Special cases............................................................... 45

3.11.7 Tripdogs/foot controls ................................................................45

3.11.8 Work holding and driving (loading) ............................................46

3.11.8.1 Loading of parts into the machine ............................... 46

3.11.9 Fire prevention and protection ...................................................46

3.11.10 Hydraulic and pneumatic pressure protection .........................46

3.11.11 Lighting ....................................................................................47

3.12 Control systems ..................................................................................47

3.12.1 Electrical ....................................................................................47

3.12.1.1 General construction ...................................................47

3.12.1.2 Disconnect ...................................................................47

3.12.1.3 Operating control .........................................................47

3.12.1.4 Low-voltage protection ................................................47

3.12.1.5 Voltage ........................................................................ 47

3.12.1.6 Grounds .......................................................................48

3.12.1.7 Component failure .......................................................48

3.12.1.8 Emergency stop .......................................................... 48

3.12.1.9 Identification ................................................................48

3.12.1.10 Control component location .......................................48

3.12.2 Unintended operation ................................................................48

3.13 Airborne contaminants, flying particles and sparks............................. 49

3.13.3 Spark hazard prevention ...........................................................49

3.14 Coolant, lubrication, hydraulic fluid, compressed gas .........................49

3.15 Noise level .......................................................................................... 49

4 Safety guards ................................................................................................50

4.1 General requirements ...........................................................................50

4.2 Portable grinding................................................................................... 51

4.2.1 Design of safety guards ..............................................................51

4.2.2 Safety guards for specific wheel types ........................................ 51

4.2.2.1 Type 1 grinding wheels, cutting-off wheels,and tuck pointing wheels ............................................... 51

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4.2.2.2 Vertical and angle grinders,Types 6 and 11 cup wheels ........................................... 52

4.2.2.3 Vertical and angle grinders,Types 27, 28 and 29 depressed center wheels ............. 53

4.2.3 Maintenance of safety guards for portable machines .................53

4.2.4 Strength of safety guards ............................................................53

4.2.4.1 Portable electric grinders ............................................... 53

4.2.4.1.1 Performance criteria for guard designfor portable electric grinders ..........................55

4.2.4.2 Portable air grinders ...................................................... 56

4.3 Stationary grinding ................................................................................57

4.3.1 Guard exposure angles ............................................................... 57

4.3.2 Bench and pedestal grinders ...................................................... 57

4.3.2.1 Exposure adjustment,bench and pedestal grinders .........................................58

4.3.3 Floorstand grinders .....................................................................59

4.3.3.1 Floorstand grinders exposure adjustment .....................59

4.3.3.1.1 Self-closing guard ..........................................60

4.3.3.1.2 Inspection and maintenanceof self-closing guards .................................... 61

4.3.3.1.3 Design criteria for a self-closing guard ..........61

4.3.4 Cylindrical grinders ...................................................................... 62

4.3.5 Surface grinders .......................................................................... 62

4.3.6 Swing frame grinders ..................................................................63

4.3.6.1 Swing frame grinders using straight wheels .................. 63

4.3.6.2 Swing frame grinders with cup wheels ..........................63

4.3.7 Semiautomatic snagging machines ............................................63

4.3.8 Top grinding ................................................................................. 63

4.3.9 Masonry saws .............................................................................64

4.3.10 Concrete saws .......................................................................... 64

4.3.11 Wall saws ..................................................................................65

4.3.12 Rotary tool (burr) grinding .........................................................65

4.3.13 Cutting-off wheel grinding .........................................................65

4.3.14 Band type guards for stationary grinding machines .................. 66

4.4 Construction guide for steel guards ...................................................... 69

4.4.1 Material requirements and minimum dimensionsfor portable grinding machines ...................................................70

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4.4.2 Material requirements and minimum dimensionsfor stationary grinding machines ................................................70

4.4.3 Optional materials .......................................................................70

4.4.4 Cutting-off wheels over 16" diameteroperating at higher than standard speeds ..................................70

4.4.5 Wheel guard with removable side covers ...................................71

4.4.6 Material specifications ................................................................. 71

5 Flanges .........................................................................................................72

5.1 General requirements ...........................................................................72

5.1.1 Type 1 cutting-off wheels .............................................................73

5.1.2 Flanges — Types 27, 27A, 28, 29 wheels ...................................74

5.1.2.1 Type 27A cutting-off wheels ...........................................74

5.1.2.2 Types 27, 28 and 29 wheelslarger than 5" diameter ..................................................74

5.1.2.3 Type 27 wheels 5" diameter and smaller .......................75

5.1.3 Flange types ................................................................................75

5.1.3.1 Straight flanges, relieved and unrelieved ...................... 75

5.1.3.2 Adaptor flanges .............................................................76

5.1.3.3 Sleeve adaptor flanges ..................................................76

5.2 Design, material and dimensions.......................................................... 76

5.2.1 Flange testfor bench, pedestal and portable electric grinders .....................76

5.3 Finish and balance................................................................................77

5.4 Uniformity of diameter ...........................................................................77

5.5 Recess and undercut ............................................................................78

5.6 Blotters ..................................................................................................78

5.7 Driving flange ........................................................................................79

5.7.1 Spacers, multiple wheel mounting ..............................................79

5.8 Repairs and maintenance .....................................................................80

5.9 Recessed wheels ..................................................................................81

6 Mounting .......................................................................................................87

6.1 Inspection .............................................................................................87

6.1.1 Inspection methods .....................................................................87

6.1.1.1 Visual inspection............................................................87

6.1.1.2 Ring test ........................................................................ 87

6.1.1.3 Vibration test ..................................................................89

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6.1.2 Metal centered wheels ................................................................89

6.2 Spindle speed .......................................................................................89

6.2.1 Tension speed .............................................................................90

6.3 Arbor hole size ......................................................................................90

6.4 Surface condition ..................................................................................90

6.5 Reducing bushings ............................................................................... 90

6.6 Blotters ..................................................................................................91

6.7 Flanges ................................................................................................. 91

6.7.1 Uniformity of diameter ................................................................. 91

6.8 Tightening of mounting nut and screws ................................................91

6.8.1 Single end nut .............................................................................91

6.8.2 Multiple screws ............................................................................93

6.9 Direction and length of thread on machine spindle............................... 93

6.10 Threaded hole wheels ........................................................................ 93

6.11 Mounting of abrasive discs ................................................................. 94

6.12 Mounting of plate mounted type wheels ............................................. 94

6.13 Safety guards ......................................................................................95

6.14 Mounted wheels ..................................................................................95

6.14.1 Mounted wheels on portable air grinders .................................. 95

6.15 Types 27, 28 and 29 wheels ............................................................... 96

6.16 Type 27A wheels ................................................................................. 96

6.17 Type 2 cylinder wheels .......................................................................96

6.18 Segments............................................................................................96

7 Standard speeds ...........................................................................................98

7.1 Standard speeds................................................................................... 98

7.1.1 Standard maximum speeds ........................................................ 98

7.1.2 Machine supplier's responsibility ................................................. 98

7.1.3 Wheel user's responsibility .......................................................... 98

7.1.4 Wheel manufacturer's responsibility..........................................100

7.1.4.1 Speed testing of wheels ..............................................100

7.1.4.1A Vitrified bonded wheels ................................ 100

7.1.4.1B Organic bonded wheels ............................... 101

7.1.4.1C Superabrasive wheels ................................. 101

7.1.4.2 Speed marking ............................................................102

7.1.4.3 Blade tensioning .......................................................... 102

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7.1.4.4 Segment attachment testing ........................................ 102

7.2 Speed check of machines — User's responsibility ............................. 103

7.3 Speed adjustment control — User's responsibility ............................. 104

8 Special speeds ............................................................................................105

8.1 Introduction .........................................................................................105

8.2 Requirements for special speeds .......................................................105

8.2.1 Condition A — The wheel manufacturer .................................... 105

8.2.2 Condition B — The machine supplier ........................................ 105

8.2.3 Condition C — The user ............................................................106

8.3 Wheel manufacturer's responsibility ...................................................106

8.3.1 Blade tensioning ........................................................................ 106

8.3.2 Manufacturer's test for vitrified bonded wheels ......................... 106

8.3.3 Manufacturer's test for organic bonded andall other bonded wheels, except vitrified bonded wheels ......... 107

8.3.4 Identification ..............................................................................107

8.4 Machine supplier's responsibility ........................................................ 107

8.5 User's responsibility ............................................................................108

9 General operating rules............................................................................... 109

9.1 User’s responsibility ............................................................................109

9.2 Airborne particulates control ............................................................... 109

9.3 Personal protective equipment ...........................................................109

9.3.1 Eye and face protection ............................................................109

9.3.2 Protective clothing .....................................................................109

9.4 Wheel breakage.................................................................................. 110

9.5 Wheel speed ....................................................................................... 110

9.5.1 Tensioned speed ....................................................................... 110

9.6 Flanges ............................................................................................... 110

9.7 Safety guard ....................................................................................... 111

9.8 Starting the wheel ............................................................................... 111

9.9 Vibration .............................................................................................. 111

9.10 Balance ............................................................................................. 112

9.11 Truing and dressing .......................................................................... 113

9.12 Wet grinding ...................................................................................... 113

9.13 Side grinding ..................................................................................... 113

9.14 Lubrication ........................................................................................ 114

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9.15 Machine maintenance....................................................................... 114

9.16 Work rests ......................................................................................... 114

9.17 Large hole inorganic bonded wheels ................................................ 115

9.18 Wheel discard size............................................................................ 115

9.19 Wheel type for machine .................................................................... 116

9.20 Machine conversions ........................................................................ 116

9.21 Wheel specification ........................................................................... 116

10 Mounted wheels ........................................................................................ 117

10.1 Standard maximum speeds .............................................................. 117

10.2 Work pressure .................................................................................. 118

10.3 Mandrel material ............................................................................... 118

10.4 Mounted wheels on portable air grinders.......................................... 118

Tables of Maximum Operating Speeds for Mounted Wheels .......................... 119

Annexes

A ................................................................................................................138

B ................................................................................................................139

C ................................................................................................................143

Index ...............................................................................................................146

ix

Foreword (This Foreword is not part of American National Standard B7.1-2000)

In 1917, The Grinding Wheel Manufacturers and the Machine Tool Buildersbegan to recognize a need for codification and standardization of the basicrequirements for safe operation of abrasive grinding wheels. By 1922,these two groups had completed a tentative draft of requirements for anAmerican Standard. It was reviewed, revised, and subsequently publishedin 1926 under the auspices of the American Standards Association (nowthe American National Standards Institute) as the “American StandardSafety Code for the Use, Care and Protection of Abrasive Wheels.” TheStandard has been revised in 1930, 1935, 1943, 1947, 1956, 1964, 1970,1978, 1988, and 1995.

In the fall of 1993, the members of the former Grinding Wheel Institutebegan the revision of American National Standards Institute (ANSI) B7.1.Prior to this undertaking, the last major revision of the B7.1 Safety Codewas in 1988. In addition to the many changes already being discussed forthe next revision of the code, the National Machine Tool Builders Associa-tion proposed the mating of the ANSI B11.9, “Safety Requirements for theConstruction, Care, and Use of Grinding Machines,” standard with the B7.1standard to form a comprehensive guide for all grinding wheel users. It wasa natural union of machine builder and wheel manufacturer and so it wasagreed to combine the two standards. After two years of wrestling with allthe issues associated with the combining of the two codes, it becameapparent that there was a great deal of work still left to be done. During theperiod between the last revision and 1995, an important body of work,ANSI B74.21, “Fatigue Proof Test Procedures for Vitrified Grinding Wheels,”had been published. The publication of the new standard created a conflictwith ANSI B7.1 testing procedures and it was agreed that an Addendum toB7.1 was needed to solve the conflict while work continued on the revisionof the main body. On May 10, 1995, ANSI B7.1 was republished with anAddendum, which covered the new Fatigue Proof Test Procedure. Workcontinued on the revision of B7.1 for five more years, with additions andrevisions being made right up until the balloting process, which took placeon June 3, 1999.

The two groups which initiated the Code in 1917 have been expanded intoa Standards Committee representing nationally recognized engineering,safety, abrasive wheel and grinding machine fabricators and user associa-tions, labor organizations, insurance underwriter groups, and a govern-ment agency.

Basic to a proper understanding of the Standard is a thorough knowledgeof the nature and characteristics of abrasive wheels and the grindingmachines on which they are used. Their safety and protection devices canand must be used to limit, if not eliminate, injury or damage in case ofaccidental wheel breakage. Constant educational programs at all levelsare the best insurance against those unforeseen conditions or circum-stances which result in an industrial accident.

This standard outlines the best known practices, tests, and safety devicesfor the protection of all personnel and equipment from injury or damage incase of accidental wheel breakage. USE THEM. This, the “AmericanNational Standard Safety Requirements for the Use, Care and Protectionof Abrasive Wheels,” is specifically dedicated to vigilant safety practiceand education.

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Suggestions for improvement of this standard will be welcome. Theyshould be sent to the Unified Abrasives Manufacturers’ Association, BondedDivision, 30200 Detroit Road, Cleveland, OH 44145-1967.

The ANSI Accredited Standards Committee B7 on the Use, Care andProtection of Abrasive Wheels, which reviewed and approved this Stan-dard had the following personnel at the time of approval:

Jerry Leeds, ChairmanJ. Jeffery Wherry, Secretary

Organization Represented Name of RepresentativeAlliance of American Insurers .................................................... John W. Russell

Keith Lessner (Alt.)

American Foundrymen's Society ............................................... Dennis M. HeussnerFred Kohloff (Alt.)

Association for Manufacturing Technology ................................ Horst E. MaackBartlett, Robert L. ....................................................................... Robert L. Bartlett, P.E.Compressed Air & Gas Institute, Pneumatic Tool Section ......... Bruce Fowler

Greg Albert (Alt.)John H. Addington (Alt.)

Masonry and Concrete Saw Manufacturers’ Institute ................ Lennart GustafssonKevin Wilson (Alt.)

National Association of Governmental Labor Officials ............... Jim MarshallBrenda Reneau (Alt.)

Power Tool Institute, Inc. ........................................................... Robert ZinkEd Oldewurtle (Alt.)

Technical Engineered Products ................................................. Jerry LeedsUnified Abrasives Manufacturers’ Association

Bonded Division .................................................................... Ronald L. KarbowskiRobert A. Beebe (Alt.)John Bilko (Alt.)Richard T. Caserta (Alt.)Tom Casey (Alt.)Edwin F. Sharpe (Alt.)

Coated Division ..................................................................... J. Jeffery WherrySuperabrasives Division ........................................................ J.H. Kilmer

J. Jeffery Wherry (Alt.)U.S. Department of Labor .......................................................... Richard Sauger

Frank A. Smith (Alt.)

The personnel of Technical Committee No. 1 Use, Care and Protection ofAbrasive Wheels, Machines and Accessories was as follows:

Robert A. Beebe, ChairmanJ. Jeffery Wherry, SecretaryHorst E. Maack, B11.9 Liaison James Bair

John M. BilkoRichard T. CasertaTom CaseyBruce FowlerRoger A. GaryRussell HerlacheDennis M. HeussnerSteve HooperRonald L. KarbowskiJim Koch

Kenneth E. LauckJerry LeedsEdward K. MoffleyJoseph F. Ondrus, Jr.George Reitmeier, P.E.Richard SaugerThomas H. ServiceEdwin F. SharpeJack ShoemakerGeorge C. Sipe, Jr., P.E.Robert L. Zink