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Parts ranked by major diameter

77.94 mm

2-1/2" NH fire hose thread (NST) has the highest major diameter in the dataset, at 77.94 mm.

Which part has the highest major diameter?

2-1/2" NH fire hose thread (NST), at 77.94 mm, tops the 32 parts we hold a published major diameter for. The full ranking is below.

#	Parts	Major diameter
1	2-1/2" NH fire hose thread (NST)	77.94 mm
2	2" camlock (cam-and-groove) coupling	63.0 mm
3	S60x6 IBC buttress thread	60.0 mm
4	1-1/2" NH fire hose thread (NST)	50.55 mm
5	1-1/2" BSP parallel (G1-1/2 / BSPP)	47.803 mm
6	1-1/4" BSP parallel (G1-1/4 / BSPP)	41.91 mm
7	1" NPT (National Pipe Taper)	33.4 mm
8	1" BSP parallel (G1 / BSPP)	33.249 mm
9	1" BSP tapered (R1 / BSPT)	33.249 mm
10	1" NPSH straight hose thread	32.89 mm
11	Garden Hose Thread (GHT / NH)	26.99 mm
12	3/4" NPT (National Pipe Taper)	26.67 mm
13	3/4" BSP parallel (G3/4 / BSPP)	26.441 mm
14	3/4" BSP tapered (R3/4 / BSPT)	26.441 mm
15	3/4" NPSH straight hose thread	26.29 mm
16	Female aerator thread (M24 x 1 / 55/64"-27)	24.0 mm
17	M22 x 1.5 pressure-washer, 14 mm bore	22.0 mm
18	M22 x 1.5 pressure-washer, 15 mm bore	22.0 mm
19	Male aerator thread (M22 x 1 / 15/16"-27)	22.0 mm
20	Female aerator thread (M22 x 1)	22.0 mm
21	1/2" NPT (National Pipe Taper)	21.34 mm
22	1/2" BSP parallel (G1/2 / BSPP)	20.955 mm
23	1/2" BSP tapered (R1/2 / BSPT)	20.955 mm
24	Male aerator thread (M18 x 1)	18.0 mm
25	3/8" NPT (National Pipe Taper)	17.15 mm
26	3/8" BSP parallel (G3/8 / BSPP)	16.662 mm
27	3/8" BSP tapered (R3/8 / BSPT)	16.662 mm
28	1/4" NPT (National Pipe Taper)	13.72 mm
29	1/4" BSP parallel (G1/4 / BSPP)	13.157 mm
30	1/4" BSP tapered (R1/4 / BSPT)	13.157 mm
31	1/8" NPT (National Pipe Taper)	10.29 mm
32	1/8" BSP parallel (G1/8 / BSPP)	9.728 mm

Data as of 2026-09-05.