Shear Load Calculation
Shear Load Calculation
Shear Load Calculation
The following design considerations should be evaluated to maximise the security and safety of the fastening assembly using Recoil wire inserts. Boss Dimensions Boss thickness is a function of size and strength requirements and also design of components. For optimum strength, the minimum wall thickness should be twice the maximum diameter of the STI Recoil Tap. For minimum requirements, a wall thickness of twice the bolt diameter to centre line may be adequate.
Boss Thickness
Diameter of STI Tap C Diameter of STI Tap
Minimum Material Thickness The recommended minimum material thickness for through-hole applications is equal to the nominal length of the insert plus one pitch. This allows for proper countersinking and installation of the insert at 3/4 to 1 1/2 pitches below the surface of the component. In design critical applications, the minimum thickness may be reduced by eliminating the countersink and installing the insert to 1/4 to 1/2 pitch below the surface. Class of Thread Fit All Recoil inserts are produced to exacting tolerances where installation into the tapped hole will conform exactly to the parent material thread characteristics. It is therefore important that the tapped hole tolerances of either 2B or 3B (unified threads), or the applicable 4H5H and 5H (metric threads) combinations must be carefully controlled by precise tapping and gauging operations. Gauging Recoil inserts, when installed correctly in tapped and gauged holes, will conform with the tapped hole dimensions once the insert has been seated. Gauging of the tapped hole with the appropriate gauges prior to installing Recoil inserts is therefore highly recommended. Bolt Engagement Maximum strength of the bolted insert assembly will be achieved if the bolt or screw engages the full length of the insert. Ideally, the minimum bolt projection for safe engagement should be at least two pitches beyond the last coil of the insert. Tang Removal To achieve the optimum bolt engagement and hence maximum strength, the tang should be removed from the insert. Exceptions to this recommendation may be necessary in certain blind-hole applications involving light tensile bolt loading.
Edge Dimensions The minimum edge distance recommended is the maximum diameter of the STI tap measured from the edge of the material to the centre line of the hole.
Edge Thickness
Diameter of STI Tap C
33
800-453-1692
Assembly Design
Design Method
The ultimate consideration is to design an assembly that balances the tensile strength of the bolt material against the shear strength of the parent material. With insert lengths available in 1, 1 1/2, 2, 2 1/2, and 3 times the nominal thread diameters, there are engagement lengths available to produce an assembly thread system where the bolt will fail without damage to the parent material or thread. The bolt must be fully engaged along the entire length of the insert to obtain this position. Selection of the correct length insert can be determined from Table 1 refering to values for bolt ultimate strengths and parent material shear strengths. For intermediate strength value, use the next higher bolt tensile value or the next lower parent material shear strength. Assembly strength is a function of shear area and the shear strength of the parent material, tensile strength and cross sectional area of the bolt. Table 1 provides a recommendation of the nominal length of insert which should be selected for a parent material of a certain shear strength, so that when a bolt is used with defined tensile properties, tensile failure of the bolt should occur before the insert is stripped away from the material in which it was inserted.
Note: Inserts are available in different lengths which are measured by the diameter of the thread. For example the length of a 3D insert would be three times the diameter. Note: Table 1 is for guidance only. It remains the responsibility of the user to ensure that the insert nominal length chosen is suitable for the particular application concerned.
Design Method
The following Procedure can be used to verify a joint design incorporating a wire thread insert. 1. Select size and strength of bolt to be used. (refer to table 2) 2. Determine tensile failure load of the selected bolt. 3. Determine shear strength of parent material for the installation of the insert. (refer to table 3) 4. Determine length of insert based on the shear strength capability if parent material.
Note: Information in refering to joint strength is intended as a guide only. Engineering design configurations must be sought when exact calculations are required.
Select Size and Strength of bolt to be used Step One, M16 x 2.0, Type SHE Grade 8 16.0 mm Nominal Diameter 2.0 mm 1034 MPa (Refer Table 2) TPI Tensile Strength
34
800-453-1692
Assembly Design
Table 2 Strength, Bolt (Metric)
BOLT GRADE
SAE Grade 1 1/4" to 1" SAE Grade 5 1/4" to 1 1/2" SAE Grade 7 1/4" to 1 1/2" SAE Grade 8 1/4" to 1 1/2" ASTM A354 BC 1/4" to 2 1/2" BD 1/4" to 2 1/2" Socket head screw products 300 Series stainless steel (Cold Forged) 304 316
700 700
101,000 101,000
Step Two: Min Thread Diameter Shear Area Tensile Failure Load
Determine tensile failure load of selected bolt 13.797mm (handbook) Min Thread Diameter 149.5mm2 (calculated)* Shear Area Tensile Failure Load 154.589kN (calculated)#
*Area based on minor thread diameter. #Parent material shear strength must exceed this.
*Area based on minor thread diameter. #Parent material shear strength must exceed this.
Determine shear strength of parent material for the installation of the insert (refer Table 3) 2024 Wrought Aluminum, T64 temper 283 MPa (Refer Table 3) Type Shear Strength 5083 Wrought Aluminum, annealed Condition 25,000 psi (Refer Table 3)
SHEET & PLATE 1200 0 2024 T62 5005 H34 5251 H34 5083 0 5083 H321 7075 T6
SHEET & PLATE 1200 0 2024 T62 5005 H34 5251 H34 5083 0 5083 H321 7075 T6
EXTRUSIONS (including machine rod) 1350 H112 55 2011 T3 221 2011 T6 234 2014 T6 290 6060 T5 117 6061 T6 207 CASTINGS (Properties refer to test bars only) CA401 F1-Sand 96* LM6 F1-Sand 96* A13 F1-Sand 96* AC601 T5-Sand 123* LM25 T5-Sand 123* A356 T5-Sand 123*
EXTRUSIONS (including machine rod) 1350 H112 8,000 2011 T3 32,000 2011 T6 34,000 2014 T6 42,000 6060 T5 17,000 6061 T6 30,000 CASTINGS (Properties refer to test bars only) CA401 F1-Sand 14,000* LM6 F1-Sand 14,000* A13 F1-Sand 14,000* AC601 T5-Sand 18,000* LM25 T5-Sand 18,000* A356 T5-Sand 18,000*
Shear strength of standard parent materials, (indication only refer supplier for specific properties) *Shear strength based on 60% of ultimate tensile strength.
35
800-453-1692
Assembly Design
Step Four, Nominal Diameter Pitch Pitch Diameter (min) Determine the length of insert based on shear strength of parent material 16.0 mm (Selected bolt) Nominal Diameter 0.500" (Selected bolt) 2.0 mm 17.299mm (Refer Taped Hole Data) TPI Pitch Diameter (min) 13 0.550" (Refer Taped Hole Data)
L=
L=
L = Length of fitted insert Arbitrary Constant = 0.5 (Based on shearing of the parent material occuring along the pitch diameter of the tapped hole) L =
L = Length of fitted insert Arbitrary Constant = 1.085" (Based on shearing of the parent material occuring along the pitch diameter of the tapped hole) L = 181,000 X (0.4072 L = 1.085"
L = 20.2mm
Conclusion: For this application a 16mm diameter bolt has been selected. Insert engagement of 20.2mm was calculated. The suitable diameter of the insert can be determined by dividing the length of the insert by the diameter of the bolt. For example: L/dia = 20.1/16 = 1.26 select next highest size Therefore use a 1.5D insert
Calculated Load of Assembly (kN)
200
1.5D insert failure. Load 185 kN Joint failure through bolt Selected bolt
Conclusion: For this application a 1/2" diameter bolt has been selected. Insert engagement of 1.085" was calculated. The suitable diameter of the insert can be determined by dividing the length of the insert by the diameter of the bolt. For example: L/dia = 1.085/.5" = 2.1 select next highest size Therefore use a 2.5D insert
Calculated Load of Assembly (pounds) Tensile Strength - Bolt
Selecting 3D insert provides extra allowance for safety
160
Minimum bolt failure. Load 155 kN
2D
ert
ins
2.5D insert failure. Load 27000lbs Minimum bolt failure. Load 21600lbs 2.0D insert failure. Load 21600lbs
in se rt
2.
5D
120
in s
er
30,000
220,000psi bolt
Selected bolt 181psi
2D
180,000psi bolt
80
rt
Selected parent material 283 Mpa
20,000
in se
1.5 D ins
ert
1D
in
se
rt
120,000psi bolt
rt
1. 5D
se D in
40
.5D
ins
ert
10,000
.5D in sert
60,000psi bolt
20
100
180
260
340
5,000
15,000
25,000
35,000
45,000
The shaded area in the graph indicates the region in which bolt failure will occur.
Note: Inserts are available in standard lengths which are multiples of the diameter. For example an insert with a length of 1.5D will measure one and a half times as long as the diameter when installed. Note: The example above is an indication only. Engineering design configuration must be sought when exact calculations are required.
The shaded area in the graph indicates the region in which bolt failure will occur.
1.5D = 1 1/2 times length of insert
36
800-453-1692
Diameter
Thread Identification
Thread Identification And Drill Chart Metric
DIAMETER IN INCHES THREAD SIZE MM ISO COARSE DRILL SIZE PITCH INCH MM OTHER ISO FINE DRILL SIZE PITCH INCH MM SIZE BA DIAMETER MM INCH PITCH DRILL
.079 .087 .098 .118 .138 .157 .197 .236 .276 .315 .354 .394 .433 .472 .512 .551 .630 .709 .787 .866 .945
.4 .45 .45 .5 .6 .7 .8 1 1 1.25 1.25 1.5 1.5 1.75 2 2 2.5 2.5 2.5 3
No. 42 No. 37 1/8 No. 27 11/64 13/64 1/4 9/32 21/64 13/32 31/64 37/64 21/32 47/64 13/16
2.1 2.3 2.6 3.2 3.7 4.2 5.2 6.3 7.3 8.3 9.4 10.4 11.5 12.5 13.5 14.5 16.5 18.75 20.75 22.75 24.75
0 2 4 6 8 10
8.3 9.3 10.25 11.25 12.25 13.25 14.25 16.5 18.5 20.5 22.5 24.5
*M10 X 1, M12 X 1.25, M14 X 1.25, M18 X 1.5 - popular spark plug sizes sizes above M24 available on request.
Inch
DIAMETER INCHES MM THREAD SIZE UNC BSW THREADS PER INCH UNF (SAE) BSF BSF* NPT* UNC INCH BSW MM DRILL SIZE UNF, SAE, BSF INCH MM BSP INCH NPT MM
.86 .990 .112 .125 .138 .164 .190 .187 .216 .250 .312 .375 .437 .500 .562 .625 .750 .875 1.000 1.125 1.250 1.375 1.500
2.18 2.51 2.84 3.17 3.50 4.16 4.82 4.76 5.49 6.35 7.93 9.52 11.11 12.70 14.28 15.87 19.05 22.22 25.40 28.57 31.75 34.92 38.10
#2 #3 #4 #5 (1/8) #6 #8 #10 (3/16) 3/16 #12 (7/32) 1/4 5/16 3/8 7/16 1/2 9/16 5/8 3/4 7/8 1 11/8 11/4 13/8 11/2
56 48 40 40 32 32 24 24 20 18 16 14 13 12 11 10 9 8 7 7 6 6
40
24 24 20 18 16 14 12 12 11 10 9 8 7 7 6 6
64 56 48 44 40 36 32 32 28 24 24 20 20 18 18 16 14 12 (14) 12 12 12 12 26 22 20 18 16 16 14 12 11 10 9 9 8 8
28
27
19 19 14
18 18 14
14 11 11 11 11 11
14 11 1/2
3/32 No.36 No.31 N0.29 N0.25 11/64 13/64 13/64 15/64 17/64 21/64 25/64 29/64 17/32 19/32 21/32 25/32 29/32 1 1/32 1 5/32 1 9/32 1 13/32 1 17/32
2.3 2.7 3.0 3.4 3.7 4.4 5.1 5.0 5.6 6.7 8.3 9.9 11.5 13.0 14.5 16.5 19.75 23.0 26.0 29.5 33.0 36.0 39.0
No. 37 No.31 N0.26 11/64 13/64 13/64 17/64 21/64 25/64 29/64 33/64 37/64 41/64 49/64 57/64 1 1/64 1 5/32 1 9/32 1 13/32 1 17/32
2.3 2.7 3.0 3.3 3.7 4.4 5.1 5.0 6.6 8.2 9.8 11.5 13.0 14.5 16.25 19.5 22.5 26.0 29.5 32.5 36.0 39.0
3/8
9.9
1 1/64 1 9/32
27.0 33.5
*Nominal diameters for BSP and NPT are not thread diameters but relate to the inside diameter of the pipe.
37
800-453-1692
Thread Identification
Screw Pitch Gauge
It is critical that inserts match the tapped hole exactly as some inch and metric are very close but only one is exactly right. A screw pitch gauge is the perfect tool to identify exact TPI or pitch. The bolt diameter should be measured and matched to the closest size over, relating to the TPI or pitch of the thread. In general, major diameter of bolt or male thread will always be slightly less than the exact diameter listed in the thread identification and drill chart.
Drill Sizes
Drill sizes are recommended only. The nearest standard size drill above or below is generally quite suitable for repairs and in many instances, drilling is not necessary for stripped holes. For precision tolerances, the thread identification and drill chart is an accurate guide, but final size depends on material and machining conditions. In practice BSW interchanges with UNC except at 3/16" and 1/2", SAE interchanges with UNF, except 1" UNF - 12 TPI, SAE - 14 TPI.
Thread Features
Crest
Root
38
800-453-1692
General Information
SI Units & Conversions for Characteristics of Mechanical Fastners
CONVERSION PROPERTY
Length
UNIT
metre centimetre millimetre kilogram gram tonne (megagram) kilogram per cub. metre deg. Celsius square metre squaremillimetre cubic metre cubic centimetre cubic millimetre newton kilonewton meganewton bar megapascal newton/sqmm newton-meters
SYMBOL FROM
m cm mm kg g t kg/m3 C m2 mm2 m3 cm3 mm3 N kN MN bar MPa N/m2 N-m inch inch foot ounce pound ton (224lb) pounds per cu. ft deg. Fahr sq. inch sq. ft cu. in cu. ft cu. yd ounce(Force) pound(Force) kip MPa pound/in2(psi) 2 Kip/in (ksi) inch-ounce inch-pound foot-pound
TO
mm cm mm g kg kg kg/m3 C mm2 m2 mm3 m3 m3 N kN MN bar MPa MPa N-m N-m N-m
MULTIPLY BY
25.4 2.54 304.8 28.35 .4536 984.2 16.02 (F-32)x5/9 645.2 .0929 16387 .02832 .7645 .278 .00445 .00445 .1 .0069 6.895 .00706 .113 1.356
APPROXIMATE EQUIVALENT
25mm =1 in 300mm-1 ft 1m=39.37 28g=1oz 1kg=2.2lb=35oz 1t=2206lbs 16kg/m3=1lb/ft3 0C=32 F 645mm2=1 in2 1m2=11 ft2 16400mm3=1 in3 1m3=35ft3 1m3=1.3yd 1N=3.6 ozf 4.4N=1 lbf 1kN=225 lbf 1MPa=1bar 1MPa=145 psi 7MPa=1ksi 1N-m=140 in.oz 1N-m=9 in. ib 1N-m.75 ft lb 1.4N-m=1 ft.lb
Mass
Force
Pressure
Torque
800 780 760 745 725 712 682 688 652 262 614 601 590 576 552 545 529 514 502 495 477 461 444 427 415 401 388 374 370 362 351 346 331 323 311 301 293 285
1220 1170 1114 1060 1021 940 905 867 803 775 746 727 694 649 639 606 587 565 551 534 489 474 460 435 413 401 390 385 280 361 352 335 320 312 305 291 285
72 71 70 68 67 66 65 64 63 62 61 60 59 57 56 55 54 53 52 51 49 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31
120 119 119 118 117 116 115 115 114 114 113 112 111 111 110 109 109 108 107 106 105
276 269 261 258 255 249 245 240 237 229 224 217 211 206 203 200 196 191 187 185 183 175 170 167 165 163 160 156 154 152 147 147 143 141 140 135 130 -
278 272 261 258 255 250 246 240 235 226 221 127 213 209 201 199 197 190 186 184 183 174 171 168 165 162 159 154 152 150 147 147 144 142 135 135 130 -
30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 -
39
800-453-1692
Title
Insert, Corrosion Resistant, Helical Coil, Coarse Thread Insert, Corrosion Resistant, Helical Coil, Fine Thread Insert Screw Thread - Screw Locking Insert - Standard Dimensions, Assembly Inserts,Screw Thread, Helical Coil Fastener, Test Methods Lubricant, Solid Film, Heat Cured, Corrosion Inhibiting NATO Code No. S-1738 Lubricant, Solid Film, Heat Cures, Corrosion Inhibiting Tools For Inserting and Extracting Helical Coil Inserts
Federal Specifications
FED-STD-H28 QQ-A-250 QQ-P-35 QQ-P-416 QQ-Z-325 TT-M-261 PP-H-1581
Title
Screw Thread Standards for Federal Service General Specifications for Aluminium and Aluminium Alloy, Plate and Sheet Passivation Treatments for Corrosion Resisting Steel Plating, Cadmium (Electrodeposited) Plating, Zinc (Electrodeposited) - (Superseded by ASTM B633-85) Methyl-Ethyl-Ketone (for use in organic coatings) Shipment and storage of Packing for Hardware (fastener and related items) Packaging.
SAE Specification
MA1565 MA1567 MA3279 / MA3280 / MA3281 MA3329 / MA3330 / MA3331 AS 1370 AMS 2400 AMS 2402 AMS 2410 AMS 2411 AMS 2427 AMS 2460 AMS 2645
Title
Inserts, Metric Screw Thread, Procurement Specification Inserts, metric, Standard Dimensions, Assembly Inserts, Screw thread, Metric, Free-Running Inserts, Screw Thread, Metric, Screw Locking Aeorsospace Standard - Metric Screw Threads MJ Profile Aerospace Material Standard for Cadmium Plating Aerospace Material Standard for Zinc Plating Electroplating Standard, Silver, Nickel Strike Electroplating Standard - Silver, High Temperature Applications Aluminium Plating, Ion Vapour Deposition Magnetic Particle Inspection Fluorescent Dye Penetrant Inspection
SBAC Specifications
AGS 3600 AGS 3700 AS 6733 AS 8455
Title
Insert, Screw thread, metric, screw locking, helical coil corrosion resistant steel DTD 734 cadmium plated Insert-screw thread, unified screew locking, helical coil, h.r. alloy BS HR 503 Source control drawing UNF Unplated UNF Cadmium plated
LN Specifications
LN 9039 LN 9499 GE C9F1 GE N926
Title
Aerospace, wire thread inserts, assembly and special tools Aerospace, wire thread inserts, screw locking, assembly and special tools Wire Insert Stainless steel Wire Locking Inserts for temperatuers up to 700 deg F
DIN Specifications
DIN 8140
Title
Wire thread inserts for ISO metric screw threads - tapped holes for thread inserts thread tolerances.
Title
Tapping of holes to receive wire thread inserts (ISO metric threads) Prevailing torque type wire thread inserts - Specifications for ISO metric course pitch threads Prevailing torque type wire thread inserts - Specifications for ISO metric fine pitch threads Free running type wire thread inserts - Specifications for ISO metric course pitch threads Performance of prevailing torque wire thread inserts
40
800-453-1692