Without the proper analytical tools and information, specifying the correct torque can be. Other mechanical properties hardness is a measure of a materials ability to resist abrasion and indentation. Add the engineering toolbox extension to your sketchup from the sketchup. Bolt torque calculator calculate required bolt torque. Elongation is measured by a micrometer, ultrasonic, or an embedded gauge sensor in a bolt. High strength friction grip bolts hsfg bolts are high strength structural bolts which have been tightened such as to induce tension in the bolt shank. A procedure for calculation of torque specifications for. If lubrication is to be applied to the nutbolt,multiply the recommended torque by the appropriate factor shown in the table on page 7. Inspecting tightened torque value inspection method of applied torque estimate how much torque was applied in the screw tightening, and carry out an inspection of the tightening operation with the. Engineering fundamentals of threaded fastener design and analysis. Proper bolt axial tightening force and proper tightening torque.
Suggested tightening torque1 values to produce corresponding bolt clamping loads notes. This calculator is based on the vdi 2230 guideline. Torque values should be increased by 10% for flange bolts type u6fs. It takes more force to tighten a 3410 bolt than to tighten a 31816 bolt because it is larger in diameter. Add standard and customized parametric components like flange beams, lumbers, piping, stairs and more to your sketchup model with the engineering toolbox sketchup extension enabled for use with the amazing, fun and free sketchup make and sketchup pro. The importance of tightening torque most engineers already know the importance of a high preload in maintaining joint integrity. Fc29 2 proper bolt axial tightening force and proper. Calculation of the torque mal and axial force fl on the thread. Oct 25, 2017 say you have a 8 inch wrench and figure you are applying 4 pounds of force on the wrench centered at 6 inches from the center of the nut. Add the engineering toolbox extension to your sketchup from the. Pdf bolt torque tightening procedures mohammed mujahed. For torque controlled tightening, achieving the right preload is dependent upon the correct tightening torque being specified.
The final tightening sequence is achieved smoothly and slowly. Bolts that are fully or partially threaded, with washers and nuts are called as metric bolts. Suggested tightening torque1 values to produce corresponding. In a bolted flange, the applied torque generates the axial load in the bolt. Engineering fundamentals of threaded fastener design and analysis by ralph s. The tightening torques in the following tables apply to bolts and nuts with tensile strength noted below. It should also be realised that some torque wrenches are. If lubrication is to be applied to the nut bolt,multiply the recommended torque by the appropriate factor shown in the table on page 7. Do not let the seat of a bolt or nut dent the contact area. Tightening torques for metric bolts of yield strength sy metrique diameter mm 6 8 10 12 14 16 18 20 22 24 27 30 33 36 39 42 45 48 52 56 60 64 68 m6 m8 m10 m12 m14 m16 m18 m20 m22 m24 m27 m30 m33 m36 m39 m42 m45 m48 m52 m56 m60 m64 m68. Coefficient 44 45 rs 3 tohnichi torque handbook vol. Torque control method bolt tightening is controlled by specific torque value. For rusted bolts, the value of tension may be appreciably less than that indicated by torque, hence these bolts has not been favoured for use on indian railways.
The big problem is that the load on the gasket cannot be measured directly and easily during installation. The calculator below can be used to calculate the torque required to achieve a given axial bolt force or load. Insert screw characteristics and calculate torque and the tool 3d model will be showed. Bolt torque can be checked with a tool such as a torque wrench, but without a value as a guideline, a torque wrench offers no. Custom bolt tightening solutions standard product bolt tightening solutions we are very aware that there are many diverse and specialised types of bolted joints being used throughout the industrialised world. Due to many variables that affect the torquetension relationship like human error, surface texture, and lubrication the only way to determine the correct torque is through. Too much clamping force can also cause severe problems. The fatigue strength of bolt under repeated load should not exceed the specified tolerance. Even experienced tradesmen over or undertorque bolts. As the bolt is tightened it begins to stretch and goes into a state of tension. Ratio between measuring torque and tightening torque approximate value obtained by experiment table 31.
Calculation of axial tightening force and tightening torque. Several discussions in this technical section stress the importance of preload to maintaining joint integrity. Tightening torques and the torquetension relationship all of the analysis and design work done in advance will have little meaning if the proper preload is not achieved. How to calculate the tightening torque of bolt quora. Analysis of bolt torquing by clement rajendra, pe progress energy, southport, nc 28461. Qaxial tightening force for bolt and fatigue limit the proper axial tightening force for a bolt should be calculated within an elasticity range up to load 70% of the rated yield strength when the torque method is used. Even if the bolt does not fail during assembly, it may later break under the external tensile load. The relationship between torque, the turning force, axial bolt force and gasket load can be expressed. By combining the torqueangle curves with a few simple calculations and a basic understanding of the. Calculation of axial tightening force and tightening.
Comparing the two examples below a and b it will be noted that the same resultant torque can be achieved with a lower force if the distance from the nut bolt is increased. Bolts and nuts should be cleaned and lubricated with oil. Once the desired tensile load is imparted, a restraining nut is attached preserve. In a matter of seconds, mdesign bolt determines all of the essential variables, such as the tightening torque required, safeties, stresses torsional, comparative and assembly preload among others, as well as all of the forces to be calculated and the permissible surface pressure in the bolt and nut contact area. 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. Lubricated bolts and reduced torque lubrication effect on bolt tension and torque. Bolt torque calculator determining proper torque to bolt. There are many factors that affect how much tension occurs when a given amount of tightening torque is applied. Truthfully, product information rarely supplies torque values. Improvised torque wrench improvised torque wrench with luggage scale.
Surface condition torque adjustment factors plain steel, as supplied x 1. The major diameter is the largest diameter of a screw thread. To view the full content, you will need to purchase the standard by clicking on the buy button. This is mainly due to corrosion and deformations in the bolt and nut threads. The importance of tightening torque the problem bolt. Technical data proper bolt axial tightening force and. Breakout torque cannot be accurately calculated, however, depending on conditions it can take up to 2 12 times the input torque to breakout. Calculate nut rotation for a given bolt torque definitions. Tightening torque values are calculated from the formula t kdp, where t tightening torque, lbin k. Rotational round 100% of final torque same as round 3 or 4 above. Torque control is done as a substitute characteristic. Qaxial tightening force for bolt and fatigue limit the proper axial tightening force for a bolt should be calculated within an elasticity range up to load 70% of the rated yield strength when the torque method is. The torque angle curves can also provide the necessary information to properly qualify the capability of tightening tools to properly tighten a given fastener. When loosening bolts a torque value higher than the tightening torque is normally required.
Accepted formulae relating torque and tension, based on many tests are. Say you have a 8 inch wrench and figure you are applying 4 pounds of force on the wrench centered at 6 inches from the center of the nut. Custom bolt tightening solutions we aim to provide special tensioner solutions within one week of receiving the enquiry. It requires an inspector in the field to ensure the proper torque is applied to each bolt. There are several ways of securing parts and components to. Tightening torques and the torque tension relationship all of the analysis and design work done in advance will have little meaning if the proper preload is not achieved. Due to many variables that affect the torque tension relationship like human error, surface texture, and lubrication the only way to determine the correct torque is through.
Use of its content by anyone is the sole responsibility of that person and they assume all risk. The industry needs the best torque calculator in order to get the torque calculation. Bolt tightening torque calculation free download as excel spreadsheet. Engineering fundamentals of threaded fastener design and. The importance of tightening torque the problem bolt science.
Fortunately, torqueangle signature curves can be obtained for. In this guideline the torque required it is defined by the following expression. Lubrication reduces the friction during tightening, decreases bolt failure during installation and increases bolt service life. The rotation of a bolt torque at some point causes it to stretch tension. They are of two types, metric flange bolts and metric hex bolts. Several factors affect how much tension occurs when a given amount of tightening torque is applied. Tightening torque values are calculated from the formula t kdp, where t tightening torque, lbin k torque friction. Tightening torque range ft lbs min max other bold torque charts. 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. The electronic pdf version of this document, available free of charge. Bolt tightening torque procedure standard bolt tightening. It requires daily calibration of wrenches used in bolt tightening.
Tightening and loosening torque of the adjusting nut. Comparing the two examples below a and b it will be noted that the same resultant torque can be achieved with a lower force if the distance from the nutbolt is increased. This software can also be used on non standard bolted joints. Recommended maximum bolt loads and torque values metric coarsethreads 3. Common bolt torque values can be looked up, but finding an accurate reference isnt always easy. By overtightening the bolt, one may exceed the proof load of the bolt. Each bolt shall be tightened using a high strength nut, conforming to is 6623. Stud bolts bolting torque tables table 1 astm a193. Bolt science providing solutions to bolting problems. Tightening the nut stretches the bolt, which increases the load on the gasket. There are many methods for measuring preload see table 12. In this educational video we explore the threaded fastener, its relationship to torque, and fastener strength.
Metric bolts tightening torques engineering toolbox. In preparing this guide to torque values, the following basic assumptions have been made. How do i determine bolt torque for flanged connections. Torque is the result of multiplying the value of force applied by the distance from the point of application. The below estimated torque calculations are only offered as a guide. Bolt tightening technical data 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. Fortunately, torqueangle signature curves can be obtained for most bolted joints. The materials used for type 1 is medium carbon, type 2 contains low carbon and martensite, type 3 contains weathering steel. Higher friction results in less conversion of torque to preload.
In the method of tightening of bolts, the torque control method has been replaced by. There is also a jaw size table, but i think you should read the page for advice it would probably win the most boring web page on the internet competition. The pitch torque is calculated by the following equation. During the tightening process the bolt tension is equal to the clamp load and these value. Fe force of eccentric on gib n ft tangential force on eccentric n re radius on outer surface of eccentric mm mai tightening torque on eccentric nmm. The amount of force on a fastener is called as torque.
The powermaster bolt tightening software in many cases would recommend a preferred bolt stress based on bolt loads specified in the different bolt flange specifications. Tightening torque for stainless steel screws please use in. Torquetighteningbestpracticeguidanceonlinetrainingbrochure. As mentioned above, the tightening torque is for practical reasons the criteria normally used to specify the prestress in the screw. Pretensioning is the technique of using hydraulic pistons attached directly to the end of the fasteners. Engineering toolbox sketchup extension online 3d modeling. It takes more force to tighten a 3410 bolt than to tighten a 3816 bolt it is larger in diameter.
This online metric bolt torque calculator is used to find the torque of the ecoguard, lubricated and. The value for the friction coefficient provided by the. Iso 724 metric threads dimensions of metric threads according iso 724. Variation in friction coefficients affect the amount of preload achieved at a specified torque. Calculation of bolts according to vdi 2230 mdesign bolt. Use rotational, clockwise tightening sequence, starting with bolt no. You can tighten the bolt with the torque calculator.
Astm a325 bolt torque chart displays the torque range for different bolt sizes. Bolt tightening torque calculation personal weapons unrest. These factors include bolt diameter, bolt grade strength, and friction. Technical data suggested tightening torque1 values to produce corresponding bolt clamping loads notes. Alternatively,use the torque tension calculator on the norbar website which enables fastener and friction conditions to be modified. This assembly torque is designed to achieve a preloading in the bolt expressed in. Guidelines for use of high strength friction grip hsfg. Angle of eccentric to gib fr frictional force of gib on adjusting nut thread.
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