Asme b94 7 1980 (1995) scan (american society of mechanical engineers)

HOBS ANSI B94.7 - 1980 [REVISION OF ANSI B94.7-1966 (R 197211 ~ - - ~ - ~ ~ REAFFIRMED 1995 FOR CURRENT COMMITTEE PERSONNEL PLEASE SEE ASME MANUAL AS-1 SECRE TARlA T THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS PUBLISHED B Y T H EA M E R I C A NS O C I E T Y United Engineering Center OF M E C H A N I C A LE N G I N E E R S East tS ht r e e t N e w York, N Y 1001 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w A M E R I C A N A T I O N A SL T A N D A R D N o part of this document may be reproduced in any form, in an electronic retrieval system or otherwise, withoutthepriorwritten permission ofthe publisher Copyright by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed in U S A Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w Date of Issuance: March 15, 1981 In response to requests from both users and producers a project was initiated in December of 1961 to establish standards for gear cutting-tools Sectional Committee B5 approvedthis project at their annual meeting in 1961 and created technical committee TC-14 to prepare such standards In 1962 Sectional Committee B5 was divided and Technical Committees identified with the general area of “Metal Cutting” were transferred to a new Sectional Committee B94 The first meeting of TC-14;reporting to Sectional Committee B94, was held in December 1962 Itwas at this time decided to divide the general subject into three areas, i.e., Hobs, Gear Shaper Cutters andShaving Cutters The initial activity was to prepare a proposal for an American Standard on Hobs, using the industry standards (MCTI) as the basis for consideration A proposal covering Hobs was submitted to industry in September 1964 for review and comment All of the resulting responses were considered at a meeting of TC-14 in March 1965 and they then approved a final proposal The B94 TC-15 Editorial Committee reviewed the proposal and it was submitted on October 27, 1965 to the B94 Sectional Committee for Letter Ballot Following approval by B94 the proposal was approved by the Sponsor, ASME, and on June 22, 1966 it was approved by the American Standards Association and designated B94.7-1966 The committee was assigned the project of reviewing ASA B94.7-1966 for reaffirmation or revision The consensus was to review the existing standard and add additional hob sizes to include the larger size nominal diameter bores based on the requirements of the larger hobbing machines in use today Multiple-thread involute spline hob sizes and tolerances have also been added We have also made a number of editorial changes The current revision, after approval of the B94 Standards Committee and the Secretariat, was approved by ANSI on October 27, 1980 anddesignated B94.7-1980 iii Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled wh FOREWORD (The following is the roster of the Committee at the timeof approval of this Standard) OFFICERS A R Neinast, Chairman A M Mezey, Vice-chairman R K Buckley, Secretary AMERICAN GEAR MANUFACTURERS ASSOCIATION f M Dean, Jr., Mechanical Technology, Inc Latham, New York R C Brown, Alternate, Manager of Engineering Services, Arlington, Virginia AMERICAN SOCIETY O F MECHANICAL ENGINEERS M E Merchant, Jr., Cincinnati Milacron, Inc., Cincinnati, Ohio C J Oxford, Jr., National Twist Drill & Tool Co., Rochester, Michigan G F Wilson, Alternate, General Electric Co., Worthington, Ohio CEMENTED CARBIDE PRODUCERSASSOCIATION J A Woodward, Teledyne Firth Sterling, Pittsburgh, Pennsylvania A P Wherry, Alternate, Cemented Carbide Producers Association, Clevehnd, Ohio CUTTING TOOL MANUFACTURERSASSOCIATION E J Czopor, Falcon Tool Company, Warren, Michigan C W Jatho, Alternate, Cutting Tool Manufacturers Association, Birmingham,Michigan GENERAL SERVICES ADMINISTRATION W R Wacker, Federal Supply Service (FMET), Washington, D.C HACK & BAND SAW MANUFACTURERS ASSOCIATION OF AMERICA W B Korb, The Henry G Thompson Company, Branford, Connecticut C M Stockinger, Alternate, Hack & Band Saw Manufacturers Association of America, Cleveland, Ohio METAL CUTTING TOOL INSTITUTE W A Wagner, Cleveland Twist Drill Company, Cleveland, Ohio F A fetersen, Metal Cutting Tool Institute, Cleveland, Ohio MOTOR VEHICLE MANUFACTURERSASSOCIATION A R Neinasr, Corporate Standards International Harvester, Hinsdale, Illinois B R Ashby, Alternare, Motor Vehicle Manufacturers Association of the United States, Inc., Detroit, Michigan NATIONAL ASSOCIATION OF PUNCH MANUFACTURERS R Thomas, Dayton Progress Corp., Dayton, Ohio NATIONAL MACHINE TOOL BUILDERS’ ASSOCIATION G F Wilson, General Electric Company, Worthington, Ohio J Deam, Alternate, National Machine Tool Builder’s Association, McLean, Virginia SOCIETY O F CARBIDE ENGINEERS C H Lang, Society of Carbide Engineers, Bridgeville, Pennsylvania SOCIETY OF MANUFACTURING ENGINEERS K A Lundell, The Product0 Machine Company, Jamestown, New York H McLinden, Caterpillar Tractor Company, Peoria, Illinois W N Moore, The Ford Motor Company, Dearborn, Michigan TELEPHONE GROUP R A Agnew, Western Electric Co., Inc Chicago, Illinois S P Rogacki, Alternate, Western Electric Company Inc., Kearny, New Jersey V Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled wh AMERICAN NATIONAL STANDARDS COMMITTEEB94 Cutting Tools, Holders, Drivers and Bushings U S DEPARTMENT OF THE ARMY D L York, Liaison, U S Army Armament, Rock Island, Illinois U S DEPARTMENT OF THE NAVY J R Ruff, Naval Ship Systems Command (SEA 605)., Washington, D.C INDIVIDUAL COMPANIES H Cooper, AES Certification Institute, Troy, Michigan K Hull, The Ingersoll Milling Machine Company, Rockford, Illinois A M Mezy, Richards Bros Punch Company, Detroit, Michigan L Storrer Mohawk Tools, Inc., Montpelier, Ohio A Ashburn, McGraw-Hill, New York, New York TECHNICAL COMMITTEE 14, GEAR CUTTING TOOLS Herbert Gregg, Chairman, Star Cutter Company, Farmington, Michigan Norman Nau, Secretary, Union/Butterfield, Litton Industries, Athol, Massachusetts Alfred N Ackerson, Chrysler Corporation, New Process Gear Division, Syracuse, New York Charles C Fry, Marion Power Shovel Division, Dresser Industries, Inc., Marion, Ohio P W Kelly, Barber-Colman Company, Cutting Tool Division, Loves Park, Illinois Richard Newnlan, National Broach and Machine Division, Lear Siegler, Inc., Detroit, Michigan David W Patch, Fairfield Manufacturing Company, Inc., Lafayette, Indiana Wilbur Pergande, Illinois/Eclipse, Chicago, Illinois Gene C Pfalzyraf, John Deere Tractor Works, Waterloo, Iowa H E White, Caterpillar Tractor Company,Basic Engine, Peoria, Illinois vi Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w TUBULAR RIVET AND MACHINE INSTITUTE S Rooney, Alternate, Hi-Pro Tool Company, New Bedford, Massachusetts CONTENTS 1.SCOPE 2.PURPOSE 3.DEFINITIONOFAHOB DESCRIPTION OF HOB TYPES COVERED 5.NOMENCLATU RE 6.TABLES Page 1 1 TABLES Single Thread Coarse Pitch Hob Sizes for Ground and Unground Hobs Multiple Thread Coarse Pitch Hob Sizes for Ground and Unground Hobs Single ThreadFine Pitch Hob Sizes for Ground and UngroundHobs Multiple Thread Fine Pitch Hob Sizes for Ground and Unground Hobs Single Thread Combination Pitch Hob Sizes for Ground and Unground Hobs Single Thread Hob Sizes for Parallel Side Splines Single Thread Hob Sizes for 30" 37.5" and 45" P.A Involute Splines Multiple Thread Hob Sizes for 30" 37.5" and 45" P.A Involute Splines Roller Chain Sprocket Hob Sizes Single Thread for Chain Pitches .250thru3.000 10 Single Thread Coarse Pitch Gear Hob Tolerances 11 Multiple Thread Coarse Pitch GearHobTolerances 12 Single Thread Fine Pitch Gear Hob Tolerances 13 MultipleThreadFine Pitch Gear Hob Tolerances 14 Single Thread Hobs for Parallel Side Splines 15 Single Thread Hob Tolerances for 30" P.A InvoluteSplines 16 Multiple Thread Hob Tolerances for 30" P.A Involute Spines 17 Single Thread Hob Tolerances for 37.5" and 45" P.A Involute Splines 18 Marking Symbols 19Standard Keyways for Hobs 7 8 10 10 11 12 14 17 19 21 23 25 27 29 30 FIGURES Illustration of TermsRelating to Hobs ClimbHobbing Conventional Hobbing Hobs for ANSI B92.1 Standard 45" P.A Involute Splines Hobsfor ANSI B92.1 Standard 37.5"P.A.InvoluteSplines 6Hobs for ANSI B92.1 Standard 30" P.A Involute Splines Flat Root Major Diameter Fit and Flat Root Side Fit 3 31 31 32 32 APPENDIX A Conversion Tables from Inch t o Millimeter vii 33 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled wh AMERICAN NATIONAL STANDARD HOBS (b) Those used for cutting splines where a close tolerance is specified for the spline minor diameter on the test piece SCOPE 1.1 This standard covers types, sizes, tolerances, marking andnomenclatureforhobs of one-piece construction used for generating involute gears, involute splines, parallel side splines,involute serrations and roller chain sprockets 4.5 Hobs forRollerChainSprockets 2.PURPOSE 5.NOMENCLATURE 2.1 The purpose of thisstandard is to provide information on standard types, sizes, tolerances, markingand nomenclature of hobsto encourage uniformity in specifications 5.1 All the terms applicable to hob elements are defined and for clarity, many elements are identified in the drawings incorporated in this section In addition, this nomenclature sectionincludes definitionsfor those terms necessary to an understanding of the tolerancetablesand also some definitions of terms closely related to the subject of hob geometry Theinformation given applies to single thread hobs for American Standard Roller Chain Sprockets, (B29.1-1963) DEFINITION OF A HOB 3.1 A hob is a rotarycuttingtool with itsteeth arranged along a helix, used for generating gear teeth or other evenly-spaced forms on the periphery of a cylindrical workpiece Nomenclatureof Hob Elements and Other Terms Relatingto Hobs Adjacent Flute Spacing Variation The variation from DESCRIPTION OF HOB TYPES COVERED the desired angle between adjacent tooth faces measured in the plane of rotation 4.1 Hobs for Involute Gears The information given Adjacent Thread Spacing Variation The difference in applies to single and multiple thread hobs for cutting spur and helical gears Full depth hob tooth profiles are straight exceptfor a tip relief modificationon coarse pitch hobs the average variations obtained by traversing along the desired helical path of one thread, indexing and traversing in a similar manner on an adjacent thread Approach, See preferred term tip relief modification 4.2 Hobs for Involute Splines The information given applies to single threadhobsforcutting Standard Involute Splines (B92.1) Arbor Collar A hollow cylinder which American and is used to position the hob fits an arbor, Axial Plane A plane containing the axis of rotation 4.3 Hobs for Involute Serrations Theinformation given applies to single thread hobs for cutting American Standard Involute Serrations (B92.1) Axial Pressure Angle See definition under pressure angle The information given applies to single thread hobs in two categories as regards tolerances 4.4 Hobs forParallelSideSplines Back-off See preferred term cam relief, under relief Cam The radial drop of the form in the angular distance between adjacent tooth faces (a) Those used for cutting splines wherea close tolerance is specified for the spline key width on the test piece Chamfer A beveled surface to eliminate an other- wise sharp corner Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w ANSI B94.7-1980 ANSI 894.7-1980 v- Keyway Tooth thickness * Hob length L ! \ Lead angle > Hub' *Cylindrical or Conical Hubs Optional with the Manufacturer Tip relief modification Enlarged hob tooth FIG I L L U S T R A T I O N OF T E R M S R E L A T I N G T O HOBS ( A typical right hand single thread gear hob is shown) Climb Hobbing Rotationof a hob in theopposite direction to the feed of the hob relative to the work- nate piece at the point of contact (See Fig ) a sharp internal corner Finishing Hob One which will producetheworkpiece tooth profile to final finished hobbed dimen- Clutch Keyway See term keyway Conventional ,Hobbing Rotation of a hob in the same direction as the feed of the hob relative to the workpiece at the point of contact.(See Fig 3) sions Flute A longitudinal groove either straight or helical that forms the tooth face of one row of hob teeth and the backs of the preceding row It also provides chip space (See Fig 1) Cutting Face width The axial length of the relieved portion the of A curved surfacejoining two surfaces to elimi- hob (See Fig 1) Speed* The peripheral linea' 'peed from rotation:, usually expressed as surfacefeet per minute (sfm) Flute Helix Angle The angle which a helical tooth face makes with an axial plane, measured on the hob pitch cylinder Drawbar A rod which retains an arbor,adapteror hob shank in tlhe spindle Flute Lead The axial advance of helical a in one turn around theaxis of a hob Fillet A curved line joining two lines to eliminatea internal sharp face corner tooth face Flute Lead Variation The deviation of a hob tooth thefrom desiredsurface helical Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD HOBS ANSI 894.7-1980 Hub Diameter Runout The total variationin distance of the hub periphery from the axis I I Part being hobbed radial Hub Face The side surface of the hub (See Fig 1) Hub Face Runout The total axial variation of the hub face from a true plane of rotation Key A mechanical member through which the turn- ing force is transmitted to the hob tooth Keyseat The pocket, usually in the driving element, in which the key is retained Feed direction + Keyway A slot through which theturning force is transmitted to the hob May be either a longitudinal slot through the hole or a transverse slot across the hub face If the latter, itis called a clutch keyway FIG CLIMB HOBBING Lead The axial advance of a thread for one complete turn, or convolution (See Fig 1) Full Top Radius Continuous radius tangenttotop and side cutting edges LeadAngle The angle between a tangent to a helix and a plane of rotation In a hob, lead angle usually refers specifically to theangle of thread helixmeasured on the pitch cylinder (See Fig 1) Generated Fillet At the bottom of the hobbed form a fillet joining therootdiameter with the desired generated form This fillet is not a true radius Generated Fillet Height On the hobbed workpiece, the radialdistance fromtheroot diameter tothe point where the generated fillet joinsthe desired generated form Lead Variation The axial deviation of the hob teeth from the correct thread lead Left Hand Hob One whose thread helix corresponds to that ofa left hand screw Helical Flute Hob One whose flutes are helical The hand of the helix is usually opposite that of the hob thread and of such lead that the flutes are normal to the hob threadat the hob pitch diameter See preferred term axial pitch, under LinearPitch pitch Linear Pressure Angle See preferred term axial pressure angle, under pressure angle High Point See preferred term protuberance Hob Addendum Radial distance between the top of the hob tooth and the pitch cylinder Lug An extensionofhobtooth profile above the nominaltopcutting edge Sometimes called spurs or prongs Hob Arbor A device to mount in or on the spindle of a hobbing machine, which is designed to carry and drive an arbor-type hob JobDedendum In topping hobs, the radial distance Part being hobbed between the bottom of the hob tooth profile and the pitch cylinder tooth Hob Length Overall length of hob.(See Fig 1) Hob Runout The runout of hob when mounted in a hobbing machine, measured radially on hub diameter, and axially on hub face Hub A qualifyingsurface ateachendof an arbor type hob which is provided for checking diameter and face runout (See Fig 1) Feed direction FIG CONVENTIONAL HOBBING Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled wh AMERICAN NATIONAL STANDARD HOBS HOBS ANSI B - Multiple ThreadHob One whose teeth are arranged is preferred to the term Linear Pitch (SeeFig Lead) Linear Pztch See preferred term Axial Pztch Normal Circular Pitch The distance between corresponding elements on adjacent hob thread sections measured along a helix that is normal to the Thread Helix in the Pitch Cylinder Normal Diametral Pitch (3.1416) divided by the Normal Circular Pitch along two or more parallel helical threads which are so spaced that the lead of the thread is equal to the axial pitch of the hob multiplied by the number of threads Non-adjacent Flute Spacing The variation from the desired angle between any two non-adjacent tooth faces measured in the plane of rotation Non-topping Hob One which produces only the sides A transverse section of thehob pitch cylinder (See Fig 1) PitchCircle and root diameter of the workpiece profile, but does not finish the (outside diameter of the workpiece and does not produce an obvious chamfer at the tip of the workpiece form Such a hob may producea small amount of gear tooth tip modification Pitch Cylinder A reference cylinder in a hob from which design elements, such as lead, lead angle, and tooth thickness are derived (See Fig 1) Normal Circular Pitch See definition under pitch Pitch Diameter The diameter of the pitch cylinder Normal Module The normal module of a gear equals Pitch Point The point at which a tooth profile inter- the pitch diamleter in millimeters divided by the number of teeth sects the pitch cylinder (See Fig 1) Pre-Grind Hob One which leaves a specified amount of stock on the sides, and sometimes the bottom, of the workpiece tooth profile to allow for final finishing by grinding Such a hob may have a modified profile to distribute the stock left on the workpiece to best suit the grinding process used Normal Plane A plane perpendicular to a pitch cylin- der helix Normal Pressure Angle See definition under pressure angle Number of n7reads In multiple thread hobs, the number of parallel helical paths along which hob teeth are arranged, sometimes referred to as number of starts Pre-Shave Hob One which leaves a small amount of stock on the sides of the workpiece tooth profile to allow for final finishing by shaving Such a hob may have a modified tooth profile so that stock left on the workpiece is best distributed for finishing by shaving Offset See preferred term rake offset Outside Diameter The diameter of the cylinder which containsthe tops of the cutting edges of the hob teeth (See Fig 1) Pressure Angle The angle between a tooth profile and cal bearing surface opposite the driving end a line perpendicular to the pitch cylinder at the pitch point In hobs, the pressure angle is specified in the normal plane or in the axial plane Axial Pressure Angle The Pressure Angle as measured in an Axial Plane The term Axial Pressure Angle is preferred to the term Linear Pressure Angle Normal Pressure Angle The Pressure Angle as measured in a Normal Plane Pitch The distance between corresponding, equally Protuberance A modification near the top of the hob Outside Diameter Runout The total variation in the radial distamce from the axis to the tops of the hob teeth Pilot End On shank type hobs, a cylindrical or coni- tooth which produces undercut at the bottom of the tooth of the workpiece spaced hob thread elements along a given line or curve The use of the single word pitch without qualification may be confusing Specific terms such as normal dimetral pitch, normal circular pitch, or axial pitch are preferred Axial Pitch The pitch parallel to the axis in an axial plane between corresponding elements of adjacent hob thread sections The term Axial Pitch Rake The angular relationship between thetooth face and a radial line intersecting the tooth face at the hob outside diameter,measured in a plane perpendicular to the axis Negative Rake The condition wherein the peripheral cutting edge lags the tooth face in rotation Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD ANSI 694.7-1980 Table 14 (Part B) Single Thread Hobs for Parallel Side Splines (Continued) Spline Tooth Thickness Held Tolerances for Hob Manufacturers Test Cuts Total Spline Element Tolerances (Ten Thousandths of An Inch) I Major Diameter of Splines in inches Number Of Teeth Element Tooth Thickness Minor Dia I 10 C Tooth Thickness Minor Dia D Tooth Thickness Minor Dia A Tooth Thickness Minor Dia C D 20 20 15 25 20 I Tooth Thickness Minor Dia Tooth Thickness 30 30 I 25 20 35 30 I 40 15 10 15 15 15 20 20 20 20 25 20 I 25 20 40 20 30 35 Minor Dia I 30 25 40 30 40 30 30 50 Class A - Precision Ground Class C - Accurate Unground Class D - Commercial Unground Table 14 (Part C) Tolerances for Hob Manufacturers Test Cuts Maximum Undercut (per side) (In Ten Thousandths of a n Inch) Hob Class A C D Spline Depth (exclusive of fillet or clearance grooves) in inches 0.000 Thru 0.100 0.101 0.201 0.200 0.300 10 15 11 13 18 14 16 21 Minimum undercut is zero 22 0.301 Thru 0.401 0.501 Thru Thru Thru 0.400 0.500 0.600 16 19 18 22 27 24 20 25 30 Thru Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD HOBS ANSI B94.7-1980 Table 15 Single Thread Hob Tolerances' For 30' P.A Involute Splines (In Ten Thousandths of an Inch) C L A Hob Element S NORMAL DIAMETRALPITCH % '75 y % 'O "6 ;/ 'x4 'x2 z:z: %: RUNOUT* A A HubFace B c D A A A Hub Diameter c D A AA A Outside B Diameter C D - 5 - 5 2 4 3 4 4 - - 5 - - 4 - - - 15 20 25 45 15 20 25 45 10 10 15 17 35 17 35 20 35 3 3 2 3 2 2 2 5 5 10 4 15 15 17 12 25 30 25 1 2 22 2 2 - - 2 2 2 - 10 10 12 12 10 10 10 12 25 - - 10 107 10 10 10 - LEAD~ A A Tooth to Tooth C D A 20 - 16 - - 14 12 A A A 2 InAny B 12 22 29 One Turn 40 27 18 15 C of Helix 50 60 37 D 32 1.7 14 10 12 10 12 TOOTH A A B Pressure C Angle2 D Thickness (Minus Only) A 4 l - A A A 20 B 20 C 25 D 35 15 20 30 - - 3 8 15 15 20 25 10 15 20 10 10 20 4 12 25 1.7 1.7 1.7 1.7 1.7 1.7 2 2 3 4 10 10 10 6 11 12 2625 27 23 I :I : 11.7 11.7 1.7 1.7 2 3 3 3 10 10 10 15 20 98 11 - 11 - 10 10 10 15 15 15 20 Continued on Page 24 23 10 15 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD HOBS ANSI B94.7-1980 -7 Table 15 Single Thread Hob Tolerances1 For 30" P.A lnvoluts Splines (Continued) (In Ten Thousandths of an Inch) NORMAL DIAMETRAL PITCH Element FLUTES Adjacent Flute $;pacing3 Non-Adj,acent Flute :;pacing3 Flake to Cutting Depth4 \ A A B C D A A B C D 50 - 40 60 4A A B C D 4A A B C D 30 30 50 I 20 30 30 Flute L.ead Ove Cutting Face Width - 20 20 20 ~ 10 15 15 25 30 40 60 60 - - - 15 10 15 15 25 15 -8 10 15 15 25 ~ 30 30 30 50 50 50 50 60 50 50 100 80 80 - - - - 8 7 20 7 7 20 Up Thru 20 50 80 10 10 10 10 17 15 25 10 10 10 20 10 20 15 25 40 40 60 15 25 40 40 60 15 25 40 40 35 35 3 3 3 10 10 10 17 - 50 70 - 3 3 5 5 15 20 30 30 50 60 40 - ~ 20 15 15 - - 5 10 5 10 5 10 15 15 23 5 10 - Over Thru 30 30 30 25 25 25 25 15 15 3 3% 45 HOLE DIAMETER in inches 1.250 \A Hole A Diameter B Plus Only C D NOTE: 10 10 10 20 CUTTING FACE WIDTH in inches Over Thru Over Thru 10 10 10 10 15 UOLE 10 ~ 15 30 100 30 0.500 2 2 2 3 and Smaller 2 2 1.Except forLEAD, thesetolerances apply for all hob diameters For hob diameters larger than those recommended for standard hobs, the LEAD tolerances shall be increased by a factor of one-half of the percent oversize Total indicator variation Compared against master index plate Radial (zero rake) tooth faces are standard See Figure for Basic Hob Tooth Form (Page 32) 24 0.750 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD HOBS ANSI 894.7-1980 Table 16 Multiple Thread Hob Tolerances' For 30" P.A Involute Splines (In Ten Thousandths of an Inch) C L A Hob Element NORMAL DIAMETRAL PITCH S RUNOUTS Hub Face Hub Diam eter Outside Diameter & A E c D A A B c p 4 5 4 - 5 3 3 3 2 3 4 4 4 3 2 2 2 5 10 15 17 35 10 15 15 17 30 10 10 12 25 10 10 12 25 10 10 12 25 12 15 14 10 12 27 10 12 26 12 17 21 45 10 14 17 38 10 14 17 36 10 12 17 35 10 12 17 35 13 4 11 11 3 6 13 & A B C D A 15 15 20 20 25 25 45 45 10 10 15 17 20 35 35 A A - 1 2 2 - 2 - - 2 - 12 7 10 8 11 15 32 8 11 15 15 3 11 11 3 4 6 13 6 13 6 6 11 6 5 11 14 58 10 13 6 12 15 10 - 10 10 - LEAD^ InOne Axial Pitch A B D A In Three A E Axial C Pitches D Tooth toTooth 2Thread Hob A A B C D - 13 22 C27 22 29 40 60 50 A 33 20 30 37 56 70 84 A 13 21 17 - 10 18 32 37 - - 15 40 20 25 51 - 15 to Tooth 3Thread - - 13 - - - - ADJACENT THREAD SPACING 2Thread Hob 3Thread Hob A A B C D A 12 13 14 15 18 19 22 23 11 10 13 12 17 16 21 20 11 15 18 10 13 16 12 15 A A 14 A13 17 16 20 19 11 12 14 15 17 18 21 2220 23 10 13 16 19 8 11 14 17 B C D 25 12 18 10 15 13 16 - - - - Continued on Page 26 4 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled wh AMERICAN NATIONAL STANDARD HOBS HOBS A N S I 894.7-1980 Table 16 Multiple Thread Hob Tolerances' For 30" P.A Involute Splines (Continued) (In Ten Thousandths of an Inch) Hob Element C L A NORMAL DIAMETRAL PITCH 32 S TOOTH Pressure Angle2 Thread Hob Pressure Angle2 Thread Hob Thickness (Minus Only) FLUTES Adjacent Flute spacing3 Non-Adjacent Flute spacing3 Rake to Cutting Depth4 - - AA A C D 14 B 7 10 - -&A A B C D - - 10 13 16 10 13 16 20 20 25 35 15 15 20 30 4 7 10 7 10 - - - - - - - 1.7 7 10 ~ 1.7 7 _ 1.7 7 - 10 13 16 10 13 16 10 13 16 10 13 16 15 15 20 25 10 10 15 20 10 10 15 20 10 10 15 20 10 10 15 20 10 15 15 25 10 15 15 25 10 10 10 20 15 25 40 40 60 7 10 13 16 1.7 7 1.7 7 - B C D - 4A A B C D - - - - 20 30 30 50 20 30 30 50 15 20 20 30 10 15 15 25 - \A A B C D ~ 40 60 60 IO0 40 60 60 100 30 50 50 80 ~ 30 50 50 80 - - _ 4A A B C D 8 30 7 20 7 20 7 20 - - - 15 30 50 50 80 ~ 5 7 20 - 15 30 50 50 70 3 5 15 - - - - - 1.7 7 10 10 lo - - 4 10 13 16 10 13 10 10 15 20 10 10 15 20 10 10 15 5 10 10 10 10 20 10 10 10 20 10 10 10 17 10 10 10 17 15 25 40 40 60 15 25 40 40 60 15 25 35 35 50 15 20 30 30 40 3 5 10 3 5 10 3 5 10 3 5 10 - - - - - - - - - - - 3 5 15 1.7 ~ - - - - - - - 4A 10 10 10 10 10 A 24/48 48/96 - - - - Continued on Page 27 NOTE: E x c e p t f o r L E A D a n d A D J A C E N T T H R E A D S P A C I N G , apply for all hob diameters For hob diameterslarger Thesetolerances than thoserecom- mended for the smallest diameter for each pitch listed, the LEAD tolerances shall be increased by a factor of one-half of the percentoversize Total indicator variation Compared against master index plate Radial (zero rake) tooth faces are standard 26 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD ANSI 894.7-1980 Table 16 Multiple Thread Hob Tolerances For 30" P.A Involute Splines (Continued) ( I n Ten Thousandths of an Inch) CUTTING FACE WIDTH in inches UP Thru Over Thru Over Thru Over Thru 10 10 10 10 15 15 15 15 15 23 25 25 25 25 38 30 30 30 45 Flute AA Lead A Over Cut B ring Face C Width D HOLE Hole Diameter Plus O n h - HOLE DIAMETER in inches AA A 0.750 0.500 and Smaller 2 2 2 2 2 B C D Hob Element 1.250 Table 17 Single Thread Hob Tolerances' ;1 For 37.5' and 45' P.A Involute Splines 'F ( I n Ten Thousandths of an Inch) NORMAL DIAMETRAL PITCH O%' 'x0 '%2 RUN OUT^ Outside 2%8 '24 10 10 12 12 10 O%' 'x6 6%28 8%60 2 2 2 2 2 2 2 2 2 2 7 10 10 8 l2X56 LEAD^ A c 2 2 2 Tooth 3 3 In Any One Turn of Helix A C 11 17 10 10 16 10 1616 14 14 14 6 11 11 11 10 10 Tooth to 4 4 3 2 TOOTH Pressure Angle2 10 10 10 Continued o n Page 28 27 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD HOBS ANSI B94.7-1980 Table 17 Single Thread Hob Tolerances' (Continued) For 37.5" and 45" P.A Involute Splines (In Ten Thousandths of an Inch) Hob Element C L NORMAL DIAMETRAL PITCH A '%O S 'x2 ' % "%O x 4%0 "x28 8%60 % ' 12%56 FLUTES Adjacent Flute Spacing3 10 10 10 10 NonAdjacent Flute Spacing3 25 40 25 35 5 Rake to Cutting Depth4 Flute Lead Over Cutting Face Width HOLE C I ~~ Hole Diameter Plus Only NOTE: A t t - UO Thru 10 10 10 10 10 10 5 10 10 8 8 8 20 30 20 30 15 20 25 30 15 25 15 25 25 35 5 5 CUTTING FACE WIDTH in inches 1I Over Thru II Over Thru I 10 25 15 10 25 15 HOLE DIAMETER in inches 1.250 ~~ I 0.750 2 Except for LEAD, thesetolerances I 0.500 Smaller and 2 apply for all hob diameters For hob diameters larger than thoserecommended for standardhobs, the LEAD tolerancesshall be increased by a factor of one-half of the percent oversize Total indicator variation Compared against master index plate Radial (zero rake) tooth faces are standard See Figures and for Basic Hob Tooth Form (Page 31) 28 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD HOBS ANSI 894.7-1980 Table 18 Marking Symbols Hobs covered by this standard shall be marked with standard marking symbols Standard Marking Symbol Hob Element or Feature Normal Circular Pitch x.xxNCP Normal Diametral Pitch x NDP Normal Module x MOD Normal Pressure Angle xo NPA Number of Threads x THD Hand of Thread xH Whole Depth of Gear Tooth x.xxx WD Lead Angle xoxxf LA Flute Lead xxx.xx F L Positive Rake x - xxx Negative Rake NEG xo- xxx Pre-Shave PR E-S Pre-Grind PR E-G R Topping TOP Semi-Topping S-TOP Class CI-x Roughing RGH Finishing FIN Number of Teeth In Spline X-N Spline O.D x.xx OD Spline Tooth Thickness xxxT 29 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD HOBS ANSI 694.7-1980 Table 19 Standard Keyways for Hobs Nominal Hole Diameter A '0.315 (8mrn) "0.394 mm) (10 T Nominal Keyway Min 0.065 0.065 0.130 0.130 0.255 0.385 0.510 0.635 500 ,750 1.250 1.500 2.000 2.500 'Keyway is optional All dimensions in inches 30 T 0.351 0.431 0.347 0.427 0.008 0.008 03 03 05 06 06 06 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD HOBS ;, Min ANSI 894.7-1980 Full tangent radius* t - 1.100 X Ps 7- 2.1 00 Ps I HOB TOOTH 10120 DP THRU 1281256 DP "Hobs 641128 DP and finer may be made with flat crest **Required because of 45" PA to insure cutting within tolerance on minor diameter NOTE: I P = Diametral pitch of rack and is shown as the numerator Ps = Stub pitch and is shown as the denominator FIG HOBS FOR ANSI B92.1 STANDARD 45' P.A 1.5y INVOLUTE SPLINES l/,.41p rad HOB TOOTH 2.515.0 DP Thru 48/96 DP NOTE: P = Diametral pitch of rack and is shown as the numerator Ps = Stub pitch and is shown as the denominator FIG HOBS FOR ANSI 892.1 STANDARD 37.5' P.A 31 INVOLUTE SPLINES Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD HOBS HOBS ANSI 894.7-1980 Fillet Root Side Fit 1.5708 - 1.5708 Full tangent radius' Full tangent radius* HOB TOOTH 2.515 DP THRU 12/24 DP HOB TOOTH 16/32 DP AND FINER "For 11 Tooth Splines and less Tip Rad.mustbesuch Spline Standard 892.1 NOTE: as to siatisfy fillet radius requirements as specified in ANSI Involute P = Diametral pitch of rack and is shown as the numerator Ps = Stub pitch and is shown as the denominator FIG HOBS FOR ANSI 892.1 STANDARD 30" P.A INVOLUTE SPLINES y 2.200 Min Ps "I/ 0.075 P 30 deg + 0.002 0.780 Ps + 0.000 -[x0.032 \/ t 2.515 "A" Max L 63 deg + 0.003 HOB TOOTH 2.515 Thru 32/64 DP I DIMENSION "A" i n inches 316 418 6112 5/10 8/16 0.1560 0.0905 0.121 10/20 12/24 16/32 20140 0.0244 0.0325 0.0390 0.0487 0.0163 0.0122 0.0195 0.0650 0.0157 0.0204 0.0087 0.0282 0.01 0.0344 26 0.1466 24/48 Major Diameter Fit Side Fit The hob tooth formshown is used t o hob both Flat Root Major Diameter Fit and Flat Root Side Fit Splines, however, 892.1 does not require a tooth chamfer a t the major diameter of Flat Root Side Fit Splines NOTE: P = Diametral pitch of rack and is shown as the numerator Ps = Stub pitch and is shown as the denominator FIG FLAT ROOT MAJOR DIAMETER FIT AND FLATROOT SIDE FIT 32 32/64 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w AMERICAN NATIONAL STANDARD 0.0 0.04 CONVERSION TABLES FROM INCH TO MILLIMETER Any dimension in this standard can be converted by the addition of its components from the tables in this Appendix Consider theactual or implied precisior o f the values incustomaryunits in determiningthenum- ber o f significantdigits to be retained in the SI equivalents (For an explanation of conversion techniques, see American National Standard Metric Practice Guide, ANSI 22101.1-1976) mm inch mm 25.40 50.80 76.20 1164 0.40 101.60 127.00 152.40 132 3/64 0.79 1.19 1/16 5/64 1.58 1.98 177.80 203.20 228.60 3/32 7I64 2.38 2.78 10 11 12 254.00 279.40 304.80 118 9/64 3.1 3.57 5/32 11164 3.97 4.37 3/16 13/64 4.76 5.16 7/32 15/64 5.56 5.95 114 17/64 6.35 6.75 9/32 19/64 7.14 7.54 5116 21 164 7.94 8.33 11I32 23 I64 8.73 9.13 318 25/64 9.52 9.92 13/32 27/64 10.32 10.72 7116 29/64 11.11 11.51 15/32 I64 11.91 12.30 inch 33 inch mm 112 33/64 12.70 13.1 17/32 35/64 13.49 13.89 9116 37/64 14.29 14.68 19/32 39/64 15.08 15.48 518 41 164 15.88 16.27 21 I32 43 164 16.67 17.07 11/16 45/64 17.46 17.86 23/32 47/64 18.26 18.65 3I 49/64 19.05 19.45 25/32 I64 19.84 20.24 13116 53/64 20.64 21.04 27/32 55/64 21.43 21.83 718 57/64 22.22 22.62 29/32 59/64 23.02 23.42 15116 61 I64 23.81 24.21 31 I32 63/64 24.61 25.00 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w APPENDIX A ~~ 0.XXo 0.xxl o.xx2 O.xx3 O.xx4 0.00 0.:25 0.!51 0.03 0.28 0.53 0.05 0.30 0.56 0.08 0.33 0.58 0.03 0.04 0.05 0.76 02 :27 0.79 1.04 1.30 0.81 07 1.32 0.06 0.07 0.08 1.!52 ‘78 2.03 1.55 1.80 2.06 0.09 0.10 0.1 2.29 2.!54 2.79 0.12 0.13 0.14 O.xx5 O.xx6 O.xx7 O.xx8 0.xx9 0.10 0.36 0.61 0.13 0.38 0.64 0.15 0.41 0.66 0.18 0.43 0.69 0.20 0.46 0.71 0.22 0.48 0.74 0.84 1.09 1.35 0.86 1.12 1.37 0.89 1.14 1.40 0.91 1.17 1.42 0.94 1.19 1.45 0.96 1.22 1.47 0.99 1.24 1.50 1.57 1.83 2.08 1.60 13 2.1 1.63 1.88 2.13 1.65 1.90 2.16 1.68 1.93 2.18 1.70 1.96 2.21 1.73 1.98 2.24 1.75 2.01 2.26 2.3 2.57 2.82 2.34 2.59 2.84 2.36 2.62 2.87 2.39 2.64 2.90 2.41 2.67 2.92 2.44 2.69 2.95 2.46 2.72 2.97 2.49 2.74 3.00 2.51 2.77 3.02 3.05 3.30 3.56 3.07 3.33 3.58 3.10 3.35 3.61 3.1 3.38 3.63 3.15 3.40 3.66 3.1 3.43 3.68 3.20 3.45 3.71 3.23 3.48 3.73 3.25 3.50 3.76 3.28 3.53 3.78 0.1 0.16 0.1 3.131 4.06 4.32 3.84 4.09 4.34 3.86 4.1 4.37 3.88 4.14 4.39 3.91 4.1 4.42 3.94 4.19 4.44 3.96 4.22 4.47 3.99 4.24 4.50 4.01 4.27 4.52 4.04 4.29 4.55 0.18 0.19 0.20 4.57 4.133 5.08 4.60 4.85 5.1 4.62 4.88 5.13 4.65 4.90 5.16 4.67 4.93 5.18 4.70 4.95 5.21 4.72 4.98 5.23 4.75 5.00 5.26 4.78 5.03 5.28 4.80 5.05 5.3 0.21 0.22 0.23 5.33 5.69 5.84 5.36 5.61 5.87 5.39 5.64 5.89 5.41 5.66 5.92 5.44 5.69 5.94 5.46 5.72 5.97 5.49 5.74 5.99 5.51 5.77 6.02 5.54 5.79 6.05 5.56 5.82 6.07 0.24 0.25 0.26 6.lO 6.35 6.80 6.1 6.38 6.63 6.15 6.40 6.65 6.1 6.43 6.68 6.20 6.45 6.71 6.22 6.48 6.73 6.25 6.50 6.76 6.27 6.53 6.78 6.30 6.55 6.81 6.32 6.58 6.83 0.27 0.28 0.29 6.86 7.ll 7.37 6.88 7.14 7.39 6.91 7.16 7.42 6.93 7.19 7.44 6.96 7.21 7.47 6.98 7.24 7.49 7.01 7.26 7.52 7.04 7.29 7.54 7.06 7.32 7.57 7.09 7.34 7.59 0.30 0.31 0.32 7.82 7.87 8.73 7.64 7.90 8.1 7.67 7.92 8.18 7.70 7.95 8.20 7.72 7.98 8.23 7.75 8.00 8.26 7.77 8.03 8.28 7.80 8.05 8.31 7.83 8.08 8.33 7.85 8.1 8.36 0.33 0.34 0.35 8.38 8.84 8.89 8.41 8.66 8.92 8.43 8.69 8.94 8.46 8.71 8.97 8.48 8.74 8.99 8.51 8.76 9.02 8.53 8.79 9.04 8.56 8.81 9.07 8.59 8.84 9.09 8.61 8.86 9.1 0.36 0.37 0.38 9.114 9.40 9.85 9.1 9.42 9.68 ~ 9.19 9.45 9.70 9.22 9.47 9.73 9.25 9.50 9.75 9.27 9.52 9.78 9.30 9.55 9.80 9.32 9.58 9.83 9.35 9.60 9.85 9.38 9.63 9.88 Inch 0.00 0.01 0.02 _ _ 34 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w Inch to Millimeter (for decimal inch values of less than one inch) [Do not interpolate] Inch o.xx0 0.xxl o.xx2 O.xx3 O.xx4 O.xx5 O.xx6 O.xx7 O.xx8 0.xx9 0.39 0.40 0.41 9.91 10.16 10.41 9.93 10.19 10.44 9.96 10.21 10.46 9.98 10.24 10.49 10.01 10.26 10.52 10.03 10.29 10.54 10.06 10.31 10.57 10.08 10.34 10.59 10.1 10.36 10.62 10.13 10.39 10.64 0.42 0.43 0.44 10.67 10.92 11.18 10.69 10.95 11.20 10.72 10.97 11.23 10.74 11 oo 11.25 10.77 11.02 11.28 10.80 1.05 11.30 10.82 11.07 11.32 10.85 11.10 11.35 10.87 ll.i3 1.38 10.90 11.15 11.40 0.45 0.46 0.47 11.43 11.68 11.94 11.46 11.71 11.96 11.48 11.73 11.99 11.51 11.76 12.01 11.53 11.79 12.04 11.56 11.81 12.06 11.58 1.84 12.09 11.61 11.86 12.12 11.63 11.89 12.14 11.66 11.91 12.17 0.48 0.49 0.50 12.19 12.45 12.70 12.22 12.47 12.73 12.24 12.50 12.75 12.27 12.52 12.78 12.29 12.55 12.80 12.32 12.57 12.83 12.34 12.60 12.85 12.37 12.62 12.88 12.40 12.65 12.90 12.42 12.67 12.93 0.51 0.52 0.53 12.95 13.21 13.46 12.98 13.23 13.49 13.00 13.26 13.51 13.03 13.28 13.54 13.06 13.31 13.56 13.08 13.34 13.59 13.1 13.36 13.61 13.14 13.39 13.64 13.16 13.41 13.67 13.18 13.44 13.69 0.54 0.55 0.56 13.71 13.97 14.22 13.74 14.00 14.25 13.77 14.02 14.27 13.79 14.05 14.30 13.82 14.07 14.33 13.84 14.10 14.35 13.87 14.12 14.38 13.89 14.15 14.40 13.92 14.17 14.43 13.94 14.20 14.45 0.57 0.58 0.59 14.48 14.73 14.99 14.50 14.76 15.01 14.53 14.78 15.04 14.55 14.81 15.06 14.58 14.83 15.09 14.60 14.86 14.63 14.88 15.14 14.66 14.91 15.16 14.68 14.94 15.19 14.71 14.96 15.21 0.60 0.61 0.62 15.24 15.49 15.75 15.27 15.52 15.77 15.29 15.54 15.80 15.32 15.57 15.82 15.34 15.60 15.85 15.37 15.62 15.88 15.39 15.65 15.90 15.42 15.67 15.93 15.44 15.70 15.95 15.47 15.72 15.98 0.63 0.64 0.65 16.00 16.26 16.51 16.02 16.28 16.54 16.05 16.31 16.56 16.08 16.33 16.59 16.10 16.36 16.61 16.13 16.38 16.64 16.15 16.41 16.66 16.18 16.43 16.69 16.21 16.46 16.71 16.23 16.48 16.74 0.66 0.67 0.68 16.76 17.02 17.27 16.79 17.04 17.30 16.81 17.07 17.32 16.84 17.09 17.35 16.87 17.12 17.37 16.89 17.14 17.40 16.92 17.17 17.42 16.94 17.20 17.45 16.97 17.22 17.48 16.99 17.25 17.50 0.69 0.70 0.71 17.53 17.78 18.03 17.55 17.81 18.06 17.58 17.83 18.08 17.60 17.86 18.1 17.63 17.88 18.14 17.65 17.91 18.16 7.68 17.93 18.19 17.70 17.96 18.21 17.73 17.98 18.24 17.75 18.01 18.26 0.72 0.73 0.74 18.29 18.54 18.80 18.31 18.57 18.82 18.34 18.59 18.85 18.36 18.62 18.87 18.39 18.64 18.90 18.42 18.67 18.92 18.44 18.69 18.95 18.47 18.72 18.97 18.49 18.75 19.00 18.52 18.77 19.02 0.75 0.76 0.77 19.05 19.30 19.56 19.08 19.33 19.58 19.10 19.35 19.61 19.13 19.38 19.63 19.15 19.41 19.66 19.18 19.43 19.68 19.20 19.46 19.71 19.23 19.48 19.74 19.25 19.51 19.76 19.28 19.53 19.79 35 15.11 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled Inch to Millimeter (for decimal inch values of less than one inch) [Do not interpolate] -Inch o.xx0 0.xxl o.xx2 o.xx3 O.xx4 O.xx5 O.xx6 O.xx7 O.xx8 0.xx9 19.81 20.07 20.32 19.84 20.09 20.35 19.86 20.12 20.37 19.89 20.14 20.40 19.91 20.17 20.42 19.94 20.19 20.45 19.96 20.22 20.47 19.99 20.24 20.50 20.02 20.27 20.52 20.04 20.29 20.55 0.81 0.82 0.83 20.57 20.83 21.08 20.60 20.85 21.11 20.62 20.88 21.13 20.65 20.90 21.16 20.68 20.93 21.18 20.70 20.96 21.21 20.73 20.98 21.23 20.75 21.01 21.26 20.78 21.03 21.29 20.80 21.06 21.31 0.84 0.85 0.86 21.34 21.59 21.84 21.36 21.62 21.87 21.39 21.64 21.89 21.42 21.67 21.92 21.44 21.29 21.95 21.46 21.72 21.97 21.49 21.74 22.00 21.51 21.77 22.02 21.54 21.56 21 79 21.82 22.05 22.07 0.87 0.88 0.89 22.10 22.35 22.61 22.12 22.38 22.63 22.15 22.40 22.66 22.17 22.43 22.68 22.20 22.45 22.7 22.22 22.48 22.73 22.25 22.50 22.76 22.28 22.53 22.78 22.30 22.56 22.81 22.33 22.58 22.83 0.90 0.91 0.92 22.86 23.1 23.37 22.89 23.14 23.39 22.91 23.16 23.42 22.94 23.19 23.44 22.96 23.22 23.47 22.99 23.24 23.50 23.01 23.27 23.52 23.04 23.29 23.55 23.06 23.32 23.57 23.09 23.34 23.60 0.93 0.94 0.95 23.162 23.88 24.1 23.65 23.90 24.16 23.67 23.93 24.18 23.70 23.95 24.21 23.72 23.98 24.23 23.75 24.00 24.26 23.77 24.03 24.28 23.80 24.05 24.31 22.83 24.08 24.33 23.85 24.10 24.36 0.96 0.97 0.98 24.38 24.164 24.89 24.42 24.66 24.92 24.43 24.69 24.94 24.46 24.71 24.97 24.49 24.74 24.99 24.51 24.76 25.02 24.54 24.79 25.04 24.56 24.82 25.07 24.59 24.84 25.1 24.61 24.87 25.1 25.15 25.1 25.20 25.22 25.25 25.27 25.30 25.32 25.35 25.37 0.78 0.79 0.80 0.99 36 Copyrighted material licensed to Stanford University by Thomson Scientific (www.techstreet.com), downloaded on Oct-05-2010 by Stanford University User No further reproduction or distribution is permitted Uncontrolled w Inch to Millimeter (for decimal inch values of less than one inch) [Do no interpolate1