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• 2018-07-09

Thread Form Terms Pitch – The axial distance between threads Pitch is equal to the lead in a single start screw Lead – The axial distance the nut advances in one revolution of the screw The lead is equal to the pitch times the number of starts Screw Starts – The number of independent threads on the screw shaft example one two or four in theUnderstanding Screw Sizes – Inch Standards Screws with a diameter smaller than 1 4 quot have a nominal size indicated by a number e g 8 or 10 1 4 quot and larger diameters are shown as inches The diameter refers to the major diameter or outside edge of the threads If the screw size includes a dash with a number following it that is the number of threads per inch tpi The following provides a comprehenisve table showing the equivalant measurements in inches fractions amp decimals and millimeters for various screw sizes The second table provides the number of threads per inch for coarse UNC and fine UNF threads for various size screws and bolts The first number is the diameter of the screw bolt in inches and the second is the Imperial Thread Chart Threads per inch Major Major BSF BSCY Brass BSW UNC UNF BA Size Dia quot Dia mm 55 176 60 176 55 176 55 176 60 176 60 176 47 5 176 0G 0 0600 1 524 80 1 16 0 0625 1 588 60 10BA 0 0669 1 699 72 6 1G 0 0730 1 854 64 72 9BA 0 0748 1 900 65 1 5 64 0 0781 1 984 56 2G 0 0860 2 184 56 64 8BA 0 0866 2 200 59 1 3 32 0 0938 2 381 48 7BA 0 0984 2 Threads Per Inch Minor Diameter 75 Thread for Aluminum Brass amp Plastics 50 Thread for Steel Stainless amp Iron Close Fit Free Fit 1 0 073 48 0 076 46

The design principles of ISO general purpose metric screw threads quot M quot series threads are defined in international standard ISO 68 1 Each thread is characterized by its major diameter and its pitch ISO metric threads consist of symmetric V shaped thread In the plane of the thread axis the flanks of the V have an angle of 60 176 to each other The coarse thread series UNRC or UNC is used on the vast majority of bolts and nuts Number of threads per inch ranges from 20 threads for a 1 4 in diameter bolt to 4 threads for a 4 in diameter bolt The fine thread series UNRF or UNF is found mostly in automotive and aeronautical work Threads per inch range from 28 threads for a 1 4 Screws Rivets Hinges amp Muro T17 amp SDS Screws Socket Screws Bolts amp Nuts Construction Fasteners Nuts amp Washers www fortressfasteners co nz Fortress is a quality New Zealand brand conceived and distributed by MSL Manufacturing Supplies Ltd MSL was the innovation of the company director in 1980 starting as a small operation in New Lynn Auckland It was his Fastener and Screw Bolt Design Formula and Calculations Related Metric External Fasteners Thread Designations Sizes M1 6 M18 Metric External Fasteners Thread and Fastener Sizes M20 M50 Screw Thread Designations Minor Diameter Major Diameter Pitch Diameter ANSI ASME EXTERNAL Screw Thread Size Chart All units are in inches Unified Figures in table show amount to subtract from O D of screw to obtain specific percentages of thread Select nearest size commercial stock drill METHOD 1 Drilled Hole Size in Basic Major Dia Of Thread in Use whole numbers for of thread for 65 not 65 METHOD 2 Nominal O D Dbl Thread Depth X of Full Thread Drilled Hole Size EXAMPLE To find

SCREW THREAD INSERT TECHNOLOG STI 2 4 STI – Screw Thread Insert Tapping Options EMUGE STI Screw Thread Insert Taps are ideal for preventing the stripping of threads and are designed for threaded insert applications STI taps should be used with a precision CNC machine to ensure proper class of fit EMUGE offers a complete line of STI Tapping Solutions for a Metric Thread Size Chart Product Table Tap Size Diameter in Diameter mm Thread Count TPI Thread Pitch mm Tap Drill Size M12x1 0 4724 12 0000 26 1 000 11 mm M12x1 25 0 4724 12 0000 21 1 250 10 8 mm M14x1 5 0 5512 14 0000 17 1 500 12 5 mm M14x1 25 0 5512 14 0000 21 1 250 12 8 mm M14x1 0 5512 14 0000 26 1 000 13 mm M14x2 0 5512 American Standard Acme Screw Thread Dimensions h Basic depth of thread h9 Depth of thread with clearance K Tap drill Basic minor diameter of nut Fc Width of flat at crest of thread Fr Width of flat at bottom of space FOR 10 OR LESS THREADS PER INCH h9 Pplus 010 2 Fr 3707minus 0052 n T D plus 020 n Number of threads per inch p Pitch of American National Unified Screw Threads In this chapter you will learn the following to World Class standards Why Use Fasteners The Text Designation for the Unified National Thread Drawing and Making an External Thread Drawing and Making an Internal Thread Drawing and Making a Blind Sided Internal Thread Fastener Head Types and Purposes Drawing a NORTH AMERICAN No of Threads Inch UNC UNF UNEF 8UN NPT METRIC Dia Thread Pitch in mm mm Coarse Fine Dia Size Gauge Dia Size Gauge BRITISH No of Threads Inch BA BSW BSF BSP Major Dia Inch mm Thread Size Comparison Chart continued from facing page 19 jan 2018 C AT ALOG 1 4 R P 1 800 265 8772 F 1 888 252 6380 www com Inch and Metric

Bolt Qty Bolt Dia in Bolt Length in Raised Face Ring Joint 34 150 32 1 1 2 34 300 28 1 7 8 34 400 28 2 34 600 28 2 1 4 34 900 20 3 1 2 36 150 32 1 1 2 36 300 32 2 36 400 32 2 36 600 28 2 1 2 36 900 20 3 1 2 38 300 28 1 7 8 42 300 36 2 42 400 32 2 1 2 42 600 28 2 3 4 Created Date 1 8 2013 11 40 17 AM Bolts Screws Low Carbon Marten sitic Steel Quenched and Tempered 1⁄4 thru 1 85 000 92 000 120 000 Page 4 of 8 Proof Load psi Yield Strength Min psi Tensile Strength Min psi STANDARD BOLT IDENTIFICATION MARKINGS Identification Grade Mark Specification Fastener Description Material Nominal Size Range in This technical information is supplied MACHINE SCREWS DIMENSIONS L L Axis of screw thread Basic major diameter Minor diameter Basic pitch diameter a Tensile strength values are based on 60 000 psi and apply to carbon steel screws and SEMS only Hex and Hex Washer head machine screws of sufficient length may be wedge tensile tested Other head styles may be axial tensile tested 2A E Thread Standards and Definitions United States Canada and United Kingdom use the Unified of Unified Inch profile in accordance with the Unified and American Screw Threads – ASA B1 1 1989 UNC – Unified National Coarse UNF – Unified National Fine UNEF – Unified National Extra Fine UNS – Unified National Special UNR – Unified National Round round root ISO – inch Minor Dia Pitch Dia Major Dia Tap Drill Size 尺寸 Thread Designation螺紋規 格名稱 Class Min Max Min Max Min Max Basic 0 0118 30 318 UNM

i americannationalcoarse threadseries The American National coarse thread series is recommended for generaluse in engineering work in machine construction where conditions are favorable to theuse ofbolts screws andThread Chart American Standard UNC UNF Sales West 1 800 665 4825 Sales East 1 888 665 4825 eShop Blog Contact Us Menu Home Products Metric Fasteners Hex Head Fasteners DIN 931 ISO 4014 Partially Threaded Hex Cap Screw 8 8 Grade Bare Steel Zinc Plated 8 8 Grade Hot Dip Galvanized ISO FIT 10 9 Grade Bare Steel Yellow Zinc Plated US Hex Bolt Sizes and Thread Pitches continued mm 10 20 30 40 50 60 70 80 90 100 Title US size chart hex bolt Created Date 2 16 2017 1 04 55 PMThread Chart Threads Per Inch TPI Thread Pitch When ordering or referencing inch fasteners Threads Per Inch TPI is used instead of the thread pitch The threads per inch come directly after the thread diameter and before the length if applicable when describing an inch fastener For example a hex cap screw with a 1 2 quot thread diameter 13 threads per i nch Screw Thread Terminology 17 Standard Thread Forms 17 Thread Fits 18 TESTING OF BOLTS AND NUTS 4 19 20 1 Proof Load Test 19 2 Wedge Tensile Test 19 3 Proof Load Test for Nuts 20 ISSUE 99 PAGE 3 90138AjxH bk99IndexPgs1 8 10 13 7 00 10 11 AM Page 3 INDEX FASTENER HANDBOOK PRODUCT DESCRIPTION SECTION PAGE STRENGTH GRADE