Re: Question on Pull out Force for a Threaded Joint 02/27/2015 4:30 AM Agree Much depends on the carbon content of the steel, or whether it is an alloy etc.. eg the difference in material grade between B7 and B14 studbolts. Following are equations to provide more accurate evaluation of the shear strength of threads. Thread Tensile Stress Area Calculator. The 0.577 value corresponds to the reciprocal of the √3 term that appears in the von Mises failure criterion. I … If “LH” is added, the pipe has a left hand thread. Therefore, the stripping strength of an assembly depends on the shear strength of the nut and bolt materials. Anchor rods are embedded in concrete to support structural steel and can be used with epoxy in existing concrete applications. The screw thread on the external surface of cylinder or cone is called as the external thread. These are equations derived from FED-STD-H28/2B, 1991 and Machinerys Handbook eighteenth Edition. Pull out force of tapered pipe thread I have a steel shell made of A-36 steel with a 3/8" ipt threaded hole at the exact balance point that I have to lift. Engineer of Record shall be consulted for actual design.-Thread depth does not include roofing thickness in diameter (0.89% oversized). To determine the force required to strip the threads, multiply the shear strength by the cross sectional area being sheared. For example, “½–14 NPT” identifies a pipe thread with a nominal inside diameter of ½ inch and 14 threads to the inch, made according to the NPT standard. Increasing hole size another 0.005 in. Even if you somehow do get 9000 lb strength out of the female threads, your screw is only rated for 5720 lb tensile strength (180000 psi screw strength * .0318 in^2 tensile area). National Pipe Taper (NPT) Joint Strength MEMBER: MANUFACTURERS OF QUALITY WATER WELL ACCESSORIES U.S. & CANADA 1-800-323-6259 • FAX 1-847-669-3230 www.maassmidwest.com P. O.x 547, 11283 Dundee Road, Huntley, IL 60142-0547 • (800) 323-6259 • IL AREA (847) 669-5135 Bo ©2011, MAASS Midwest Manufacturing, Inc. UTS (Ultimate tensile strength), often shortened to TS (tensile strength) or ultimate strength is the maximum stress that a material can withstand while being stretched or pulled before failing or breaking. Formed threads held to their 35,000-lb strip-out strength when holes were 0.602 in. So as the top thread rips out it just allows the next thread to take full load and rip out until everything is zippered out. This is a quick estimate, so make sure and build some safety factor in there as well. They strictly apply to UN thread series but if the relevent metric screw thread dimensions are used they will give reasonable results. Generally as long as your length of engagement is >= 1.5x the nominal diameter of the thread, the fastener will snap before the threads pull out. Withdrawal (Pull-out) Capacities (pounds per inch of thread penetration) Assumptions:-Tabulated values above based on American Wood Council, NDS 2005 Table 11.2A-Information for reference only. Pipe thread sizes are described much as bolt sizes are, although the shapes are different. Since the male threads pull past the female threads, or vice-versa, the threads fail in shear and not in tension. If both materials are about the same in terms of strength, use the pitch diameter of the thread. dropped strip-out strength … to 0.607 in. Threaded rod is often used along with a nut and/or square plate washer when embedded in concrete to achieve required pull-out … used to hang pipe, strut, HVAC ducts. S ty. The external surface of cylinder or cone is called as the external surface of cylinder or cone is called the... Lh ” is added, the threads fail in shear and not tension. Safety factor in there as well, 1991 and Machinerys Handbook eighteenth Edition reasonable results the thread “... 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