NPT has a 60° thread where the BSP has a 55° thread. Threads commonly used in Piping - Piping thread standards; Whitworth Pipe Threads - BSPP (G) - British Standard Pipe Parallel and BSPT (R/Rp) – British Standard Tapered Pipe for pipes and tapered threads - G/R/Rp; Withworth Threads - Taps and Drill Sizes - Taps and drill sizes used for Whitworth - ISO 7 and ISO 228 threads Tap Drill Charts | British Standard Pipe Threads. Remember that NPT threads have a 60° thread flank angle, and BSPT has a 55° angle (this can be verified with a thread gauge). External Pipe Threads per. ness [mm] 1/16 28 0.907 7.723 0.304 4 1/8 28 0.907 9.728 0.383 4 6 10.2 0.4 2 1/4 19 1.337 13.157 0.518 6 8 13.5 0.53 2.3 3/8 19 1.337 16.662 0.656 6.4 10 17.2 0.68 2.3 1/2 14 1.814 20.995 0.825 8.2 15 21.3 0.84 2.6 5/8 14 1.814 22.911 0.902 16 2.6 3/4 14 1.814 26.441 1.041 9.5 20 26.9 … male thread form into a BSP female straight thread form. d3: Thread Height H1: Tap Drill Diameter mm: G1/8 : 1/8" BSPP: 9.728: 0.907: 28: 9.147: 8.566: 0.581: 8.70: G1/4 : 1/4" BSPP: 13.157: 1.337: 19: 12.301: 11.445: 0.856: 11.60: G3/8 : 3/8" BSPP: 16.662: 1.337: 19: 15.806: 14.950: 0.856: 15.00: G1/2 : 1/2" BSPP: 20.955: 1.814: 14: 19.793: 18.631: 1.162: 19.00: G5/8 : 5/8" BSPP: … BSPP MALE THREAD O.D. Thick‐. The thread pitch increases with the diameter in steps specified on a chart. inch - TPI mm inch mm inch mm inch mm inch 1/8 - 28 -02 9.5 0.37 9.6 0.38 8.4 0.33 8.6 0.34 BSPP FEMALE THREAD I.D. Thread Chart for British Standard Pipe Threads BSP, BSPP (Parallel Thread), BSPT (Taper Thread), Nominal Size, Thread per Inch, Depth of Thread, Major Diameter, Pitch Diameter, Minor diameter. For low working pressure. BSW BSPP BSPT Pipe Tap Size Pitch (TPI) Drill Size (inch) Pitch (TPI) Drill Size (inch) Pitch (TPI) Drill Size* (inch) 1/16 60 0.046 (#56) 28 0.261 (G) - - 1/8 40 0.098 (#40) 28 11/32 28 21/64 1/4 20 0.196 (#9) 19 29/64 19 7/16 5/16 18 1/4 - - - - 3/8 16 5/16 19 19/32 19 37/64 7/16 14 23/64 - - - - 1/2 12 0.413 (Z) 14 3/4 14 23/32 9/16 12 17/32 - - - - 5/8 11 35/64 14 53/64 … BSPP male and BSPP female flat face swivel require a suitable soft washer between faces to seal. These pipe threads are also known as Whitworth pipe threads. BSPT (R/Rp) – British Standard Tapered Pipe, for pipes and tapered thread; An appropriate sealing compound can be used in the thread to ensure a leakproof joint. (Threads per Inch) ISO 228, DIN 259, BS2779, JIS B0202 In Japan this thread is known as (PF) Use prefix G for parallel thread. Threads per inch: Pitch Diameter mm d2=D2: Minor Diameter Male Thd. NPT/NPS threads have a 60° included angle and have flattened peaks and valleys (this is a Sellers thread form); BSP threads have a 55° included angle and have rounded peaks and valleys (this is a Whitworth thread form). British Standard Pipe Taper (BSPT) Threads Size Chart. The flank angles of the threads are also different between NPT and BSP. Figure 5 shows a male NPT tightened into a BSPP. Thread Identifying Tools You Need Caliper – A caliper is a useful tool that measures the outside diameter of a male thread and inside diameter of a female thread. ISO 228-1, Pipe threads where pressure-tight joints are not made by the threads. Where p is the pitch. British Standard Pipe Taper (BSPT) Threads Size Chart. Where: D = Major Dia.internal thread D 1 = Minor Dia.internal thread D 2 = Pitch diameter internal thread d = Major Dia.external thread d 1 = Minor Dia.external thread NOTE: It is a common mistake to identify a BSPT (tapered) as an NPT. British Standard Pipe(BSPP, BSPF) Thread Form r = Basic Radius = * 137329 p h = Basic Depth of Thread = *640327 p p = Pitch = 1/t.p.i. BSPT FEMALE THREAD I.D. NPT/NPTF Thread Type Chart BSP Thread Type Chart PT Thread Type Chart SAE Thread Type Chart Metric Thread Type Chart Thread Seal Tape and Alternative Solutions. BSPT & BSPP SIZE & PITCH DASH SIZE BSPT MALE THREAD O.D. The thread flank angle for both tapered and parallel British threads is 55°. Whitworth's new standard specified a 55° thread angle and a thread depth of 0.640327p and a radius of 0.137329p. Although BSP is a foreign thread… The Whitworth thread system was later to be adopted as a British Standard to become British Standard Whitworth (BSW). The 1/16”, 1/8”, 1/4”, and 3/8” sizes have a dissimilar pitch, which causes a misalignment of the threads. If you have any questions please contact us or check out our fittings with BSPP/ BSPT (G) thread. NPT and BSP thread pitches (threads per inch, TPI) are listed below.