This design, including a short tapered lead, allows hand starting in a tapped hole, adjustment and alignment of parts, and an exceptionally powerful locking action. The manufacturers official manual doesnt have torque specs for these particular bolts. The taptite thread rolling screw family has been reducing the big 85 in automotive. Values in this chart are advisory only, all applications vary.
Fully threaded screws with a point for use in sheet metal. All threaded fasteners should be cleaned and inspected prior to reinstallation. Torquetension relationship for astm a193a193m b7 and. After installation, each high tensile coil of the insert expands outward with a springlike action permanently anchoring the insert. Torquetension relationship for astm a193a193m b7 and b16. Beyond that point usually about 75% of full thread the strength of the hole does not increase, yet the torque required to tap the hole rises exponentially. As for flat vs spring washers, i seem to remember it had spring washers fitted from new assuming the bolts had never been removed. Thread shear is an important failure mode for a bolted joint, and occurs when the threads shear off of either the bolt external thread shear or off of the nut or tapped part internal thread shear. A bolt is an externally threaded fastener intended to be used with a nut. Stainless steel fasteners tend to gall, especially with long run downs, prevailing torque fasteners, impact drivers, and lack of lubrication. Fortunately, torque angle signature curves can be obtained for most bolted joints.
Relating bolt torque to bolt tension from the power screw equations, eqs. Torque values for 14 and 516in series are in inchpounds. Table 3 suggested torque values and clamp loads for sae. Visit our website for the most uptodate product information. There should be enough engagement between the bolt threads and internal threads that the bolt fails in tension before the threads shear. Unlike a standard bolt, a washer face is provided under the head to provide a bearing surface when tightened. Locking action at thread periphery provides optimum holding power. The torque values can only be achieved if nut or tapped hole has a proof load greater than or equal to the bolts minimum ultimate tensile strength. For placing in the core removing hole the screw thread is conical over max. Torquetension relationship for astm a574 socket head.
The torque applied at final assembly shall include the net effect of the following. Only part of the shank of the bolt is threaded and this. The length of the thread engagement in the nut or tapped hole should be sufficient to break the bolt in tension, reference 10 pg 52. Torque values calculated from formula tkdf, where k 0. For a bolted joint with a tapped hole, if the material of tapped hole has lower strength than the bolt, the thread engagement length should be at least equal to q in order to prevent the stripping of internal thread before the failure of bolt.
Awhem recommendation for stud bolts and tap end studs for api spec 6a 7 3. K factor is a torque coefficient between bolt and receptacle. Torque values calculated from formula tkdf, where k estimated at 0. The intent of this manual is to present enough data on bolt and rivet. It is tightened or loosened by turning a nut on the bolts threads. Stud bolt with nuts point height l api type 6b flange l s figure 2. Whenever clearance is a problem, torque may be applied to the bolt head, to the high side of the torque range specified in the torque tables. General design information fastener materials bolts can be made from many materials, but most bolts are made of carbon steel, alloy steel, or stainless steel.
A screw is an externally threaded fastener designed to be threaded into a tapped hole in a part. When torque is applied in excess there is failure in threads. If the hole size is fixed, you will need to adjust the thread. Engineering fundamentals of threaded fastener design and analysis. It is a function of the materials frictional characteristics, which are based on surface finish, coatings and so on. Clamp load calculated as 75% of the proof load when specified by the standard. Only 15% of the total inplace cost of a fastening is the cost of the screw or bolt.
Hole sizes 124 thumb and wing screws 125 to 127 b7 studs and nuts stud bolts for pressuretemperature piping 21 general purpose endtoend studs 22 tap end stud bolts 23 double end stud bolts 24 bolts hex cap screws finished hex bolts 31 wrench openings for square and hex bolts and screws 32 to 33. There are several ways of securing parts and components to. The stud is screwed for 30 mm into the tapped hole and the thickness of the component with the clearance hole is 25 mm. Brake drum or rotor assembly torque specifications for mounting bolts. All torque values are based on the use of through hardened flat washers under the bolt head and nut or only under the bolt head in a tapped hole application.
Engineering fundamentals of threaded fastener design and. Torquetension relationship iso 8981 property class 4. Length cap screw machine bolt cap screw blind stud stud blind hole cap screw qty. This thread is particularly advantageous for tapped holes in. Fortunately, torqueangle signature curves can be obtained for most bolted joints. Accepted formulae relating torque and tension, based on many tests are. The torque values can only be achieved if nut or tapped hole that has a proof load greater than or equal to the bolts minimum ultimate tensile strength. This thread is particularly advantageous for tapped holes in hard materials as well as for tapped holes in thin materials where engagement is at a minimum. Threaded fasteners for plastics stanley engineered fastening. The torque values can only be achieved if nut or tapped hole has a proof load greater than or equal to the bolt s minimum ultimate tensile strength.
Torque shall be applied to the nut to the maximum extent possible when a nut is present. Accepts larger pilot hole variations than drilled and tapped holes. Pocket guide to tightening technique this booklet provides an introduction to the technique of using threaded fasteners for assembling components, the application of power tools for the assembly and the influence of tool selection on the quality of the joint. In case of tapped holes the strength of internal threads plays a very important role for calculating tightening torque. Fully threaded hex bolts are also known as tap bolts. It would also stand to reason that the greater the depth of thread, the stronger the tapped hole. During installation, the inserting tool applies torque to the tang reducing the diameter of the leading coil permitting it to enter the tapped thread.
Machine screws with a thread cutting self tapping point. Helicoil inserts are larger in diameter before installation than the tapped hole. The hotdip galvanizing is a little thicker and less uniform than the mechanical galvanizing, but it makes a difference when the nuts are overtapped. A section on design criteria covers the derivation of torque formulas, loads on a fastener group, combining simultaneous shear and tension loads, pullout load for tapped holes, grip length, head styles, and fastener strengths.
Thus the same fastener may be termed a bolt or a screw. Tapping torque vs thread strength tapmatic corporation. The values shown in the chart are to be used as a midrange guideline. For a bolt or stud in a tapped hole, the general rule is 1 to 1.
Tapping speeds material tapping speed sfm aluminum 90 110 brass 80 100 bronze 40 60 copper 70 90 copperberyllium 40. Wood screws have large threads and a smooth shank f or pulling two pieces of material together. Clamp load calculated as 75% of the proof load for socket head cap screws as specified in astm a574. Tkdw divided by 12foot pounds ttorque kfriction factor dnominal bolt diameter in decimal inches. Torque value for 12 unf bolt into tapped hole in cast iron. Machinery vibration related to poor bolting practices ken. Inch series selfsealing screw torque values see section 3. Exercise draw a similar assembly using an m24 stud. Visit our website for the most uptodate product and technical information. Rev 342009 for the signal to complete its circuit will increase. Tapped through hole tapped through holes are located in lugs around the. Also unlike a standard bolts, which have much looser. Torquetension relationship for astm a574 socket head cap. Clamp loads for grade c lock nuts equal 75% of the bolt proof loads specified for sae j429 grade 8, and astm a354 grade bd bolts.
This thread is particularly advantageous for tapped holes in hard materials. Ptfe coatings, lubrication, and assembly factors can alter these values. Bolt tightening 2 bolt tightening 21 various tightening methods various tightening methods 34 22 screw and torque relation formula between screw and torque 35 23 torque coefficient 1 formula of torque coefficient 36 2 the torque coefficient is not stable 36 3 even when the torque is stable, axial tension may vary 36. Class fit is a specification of how tightly mating external and internal threads will mesh. Studs must be used in this area to ensure that mechanical force is not imparted into the pressure containment area of the valve body, liner of lined valves, or blade. A 30 threadlocking crest is superimposed on the normal 60 thread. This provides a uniform hard, smooth bearing surface.
Works in punched, drilled, cored and extruded holes in many different metals. The following formula was used in establishing tap end stud lengths listed in the tables and is included here for convenience of industry. Unlike a standard bolt, a washer face is provided under the head to provide a bearing. There can be as many as 200 or more factors that affect the tension created in a bolt when tightening torque is applied refer to paragraph 2. A hole that creates a thread engagement of over 100% does not improve performance. It will, however, increase required drive torque, because the walls of the hole must expand to make room for the screw. Direct screwing into plastics and metals wurth industrie service. Recommended bolt torque table size recommended torque grade 2 grade 5 grade 8 188 ss bronze brass coarse fine coarse fine coarse fine coarse fine coarse fine coarse fine.
Values calculated using industry accepted formula t kdp where t torque, k torque coefficient dimensionless, d nominal diameter inches, p bolt clamp load, lb. Torque values chart for common bolt sizes n tractor club. The intent of this manual is to present enough data on bolt and rivet materials, finishes, torques, and thread lubricants to enable a designer to make a. The following formula was used in establishing stud bolt lengths listed in. By combining the torqueangle curves with a few simple calculations and a basic understanding of the. No drive torque or torque related problems and costs. Overtorquing can deform rim spacer and damage back flange. It stands to reason that it takes more power to tap to a full depth of thread than it does to tap to a partial depth of thread. Torque values chart for common bolt sizes intpi1 n m2 ftlb3 n m ftlb n m ftlb mm x pitch4 n m ftlb n m ftlb n m ftlb 14 20 7.
Threads per inch 307a astm a307 grade a sae j429 grade 5 sae j429 grade 8 f n l g 9 fnl grade 9 clamp load lbs. Torque adjustments thread locking compounds lubricants less torque is required depending on what type of lubricant, decrease approx. By combining the torque angle curves with a few simple calculations and a basic understanding of the. The higher the metal removal rate, the more torque required to produce the cut. Ncsx specification handbook for bolted joint design.
With use of corflex metallurgy, can be provided in grade strengths of high tensile bolts for use in structural applications in deep thread lengths of engagement. If the material of internal threads is having low yield strength stripping of internal threads occur. The choice between bolt or screw is really just a naming convention. Hex bolts carriage bolts lag bolts bolts with a hexagonal head with threads for use with a nut or tapped hole. Suppose that the hole in example 1 is to be tapped in steel having an ultimate shear strength 65,000 psi. So a hotdipped galvanized bolt is too big for a mechanically galvanized nut, unless someone forces it jamming on the nut. Heel type clamp thread 5818 5818 3410 ize tapped holes through holes important. Screw threads serve three basic functions in mechanical systems. Panelmounted circuit breaker torque values inlbs unless. Md 244 suggested hole sizes for tapping screws nominal hole closest drill size to screw size diameter mean hole diameter max mean min drill size drill dia. Astm a193a193m b8 and b8m class 1 torquetension guide.
1272 929 72 184 383 282 1266 331 349 950 867 1102 326 1084 1312 992 609 1547 122 959 47 1576 131 368 1271 93 454 510 1337 956 1153 1387 190 832