G1-1/2 vs R1-1/4: specs compared

Updated 05 September 2026.

47.803 mm
G1-1/2 wins on major diameter

On major diameter, G1-1/2 leads: 47.803 mm versus 41.91 mm.

SpecG1-1/2R1-1/4
DesignationG1-1/2R1-1/4
Major diameter47.803 mm41.91 mm
Threads per inch / pitch1111
Thread formparallel, 55 degreetapered, 55 degree
Seals onflat washer or bonded seal on the faceon the thread flanks with PTFE tape or paste

Questions and answers

Which has the higher major diameter, G1-1/2 or R1-1/4?

On major diameter, G1-1/2 leads: 47.803 mm versus 41.91 mm.

How do G1-1/2 and R1-1/4 compare?

On major diameter, G1-1/2 leads: 47.803 mm versus 41.91 mm.

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