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• 2018-05-23

2009 10 10 nbsp 0183 32 It s not unrealistic at all I use pipe threads all the time A pipe run does not need to be straight just the hole portion that is being threaded The thread form is governed by the dimensions and hand tight engagement is one of those dimensions It s not that difficult to hit within 177 1 turn In my experience the only thing that seems difficult to do is for the machinists National Standard Taper Pipe Threads Size NPT Chart Includes both External and internal Pipe Thread Data The taper rate for all NPT threads is 1⁄16 3⁄4 inch per foot measured by the change of diameter of the pipe thread over distance The angle between the taper and the center axis of the pipe is 1 176 47 ′ 24 quot ″ 1 7899 176 Commonly used sizes are 1 ⁄8 1 ⁄4 3 ⁄8 1⁄ 2 3 2020 10 15 nbsp 0183 32 2012 03 08 183 steris Mechanical 8 Mar 12 12 39 I agree that 7 threads is a good rule of thumb However the required min thread engagement increases and decreases dramatically with pipe size amp pitch Just looking at Table PG 39 the minimum required thread engagement varies from 4 threads to 13 threads depending on pressure and pipe size Minimum 0 033P for all pitches See table for maximum NPT symbol for the thread series and form i e National American Standard Pipe Taper L 1 Length of normal hand tight engagement This is also the L1 gauge length Longer thread engagement may be used in special applications such as flanges for high pressure use 2021 02 18 nbsp 0183 32 But since it s pipe fitting and not rocket science many of the rule of thumb solutions offered by others in the forum will generally be close enough to work Example I have a 12 quot c c measurement on a 1 2 quot pipe on an offset using 90 degree fittings How long would I need to cut the pipe to achieve recommended thread engagement Answer 10 13 16 quot Charts say

Use of Teflon tape is recommended on all plastic pipe threads wrapped 2 to 3 turns around the male thread before assembly A simple rule of thumb for installing tapered pipe threads both metal and plastic is finger tight plus one to two turns with a wrench Torque installation values can be determined per2020 10 15 nbsp 0183 32 Rule of thumb engineering designs use 75 thread engagement and a length of engagement of 1 5 times the diameter of the screw Quite often in high speed machining facilities the progammer or operator will use the largest tap drill allowed which will From engineersedge com See details HOW TO TIGHTEN NPT FITTINGS HUNKERA simple rule of thumb for installing tapered pipe threads both metal and plastic is finger tight plus one to two turns with a wrench Torque installation values can be determined per application but due to the variations involved in pipe joints such as disimiliar materials of male and threads type of sealants used and internal variations in product wall thickness a standard 2015 11 23 nbsp 0183 32 except that the thread engagement need not exceed 1 5 d s Show activity on this post I have always used the rule of thumb that the bolt has to be engaged at least one bolt diameter This partly comes from looking at structural nuts Structural nuts develop the full strength of the bolt in tension Rule of thumb 3 5 turns for hand tight then 2 3 turns power makeup So in the real world unless working to NRC specs 5 8 turns total will do A little short is preferable to too long the worst case is driving the pipe in so hard that the wedging action of the taper splits the fitting ps for 1 2 amp 3 4 14 tpi thread cut 3 4 long 11t 4 threads 1 4 quot showing after make up

A simple rule of thumb for installing tapered pipe threads both metal and plastic is finger tight plus one to two turns with a wrench Torque installation values can be determined per application but due to the variations involved in pipe joints such as disimiliar materials of male and threads type of sealants used and internal variations in product wall thickness a standard 2018 08 30 nbsp 0183 32 What is the proper thread engagement for an NPT pipe SC By Steve Calvert 08 30 18 This question has a validated answer I think I already know the answer but I wanted to ask anyway I have several sizes of aluminum conduit that we make in house for our dispensers and one end is always threaded NPT so it can be threaded into another component Some British Standard Pipe fittings are among the most popular of all foreign threads in the world today These threads come in two versions parallel BSPP and tapered BSPT The thread flank angle for both tapered and parallel British threads is 55 176 Although BSP is a foreign thread it isn t actually metric This is why it comes in Imperial sizes 1 8 1 4 1 2 3 4 etc BSP parallel The rule of thumb my pappy taught me is the fitting allowance is basically the same as the pipe you are threading So if I were to need a piece of 3 4 quot pipe to fit between two holes 12 quot on center then the actual cut and threaded piece would be 12 inches minus 1 1 2 quot or 10 1 2 quot end to end When it comes to copper fittings there are two radius to allow for Long turn and close rough A simple rule of thumb for installing tapered pipe threads both metal and plastic is finger tight plus one to two turns with a wrench Torque installation values can be determined per application but due to the variations involved in pipe joints such as disimiliar materials of male and threads type of sealants used and internal variations in product wall thickness a standard

2015 06 10 nbsp 0183 32 Thread engagement distance calculation thumb rule In case of the threads for steel – Min thread engagement distance 1 5 x base diameter of screw or bolt In case of the threads for cast iron brass – Min thread engement distance 2 x base diameter of screw or bolt British Pipe Standard fittings are among the most popular of all foreign threads These threads come in 2 versions parallel BSPP and tapered BSPT The thread flank angle for both tapered and parallel British threads is 55 176 NOTE It is a common mistake to identify a BSPT tapered as an NPT Remember that NPT threads have a 60 176 thread Basic design rules require the bolted joints to be designed so that the screw breaks before the threads strip For components with tapped holes the length engagement i e the number of threads which are engaged between the screw and the tapped hole has to be adapted to respect this criteria The critical areas of stress are as follows tensile stress area of the bolt stress 2018 03 13 nbsp 0183 32 Length of thread engagement is measured by the length of interaction between the fastener and nut member i e nut or mating material for screw For example a standard thread forming screw applied in 10mm of A simple rule of thumb for installing tapered pipe threads both metal and plastic is finger tight plus one to two turns with a wrench Torque installation values can be determined per application but due to the variations involved in pipe joints such as disimiliar materials of male and threads type of sealants used and internal variations in product wall thickness a standard

How do you measure thread length between pipe fittings Mike the rule of thumb is measure center to center then subtract the diameter of the pipe for each fitting Say 20″ is the distance btween the holes or fittings If it is 1 2″ pipe subtract a 1 2″ for each fitting for a pipe length of 19″ How are PVC pipe fittings measured Look at the end of a piece of PVC pipe Find the Normal Engagement Length of NPT Thread in Inches A 614877 963 4966 www dixonvalve com DPL410 Technical Information T Technical Thread Dimensions Nominal Dimensions of Standard Threads ODM Outside Diameter of the Male IDF Inside Diameter of the TPI Threads Per Inch Size Pipe OD Tapered Threads Straight ThreadsTitle Pipe Thread Engagement Author sh1723 Created Date 10 6 2009 12 00 00 AM2016 09 22 nbsp 0183 32 When there is adequate length of engagement start with a hole size that provide 65 thread engagement Thread forming fasteners typically provide superior drive to fail ratios when compared to thread cutting fasteners Thread cutting fasteners typically provide lower driving torque than thread forming fasteners A minimum drive to fail ratio of 1 3 is typically Minimum Thread Engagement Bolt Failure Chart Metric 332 362 165 Nominal Diameter Stress Area Class 8 8 Class 10 9 Class 12 9 Class 8 8 Class 10 9 Class 12 9 Class 8 8 Class 10 9 Class 12 9 mm mm2 mm mm mm mm mm mm mm mm mm M6 x 1 0 6 20 13 6 1 7 7 9 0 5 6 7 1 8 3 12 3 15 5 18 2 M8 x 1 25 8 36 61 8 3 10 5 12 3 7 7 9 6 11 3 16 8