Connect 3/8" BSP parallel (G3/8 / BSPP) to 1/16" BSP parallel (G1/16 / BSPP)

Stepping a G3/8 port down to a G1/16 fitting uses a parallel BSP (BSPP, ISO 228) reducing bush: a male G3/8 on the outside and a female G1/16 inside, both to the same parallel BSP form so they seal flat washer or bonded seal on the face. The major diameter goes from 16.662 mm at G3/8 to 7.723 mm at G1/16. This is a single stocked reducing part; the step is three nominal sizes.

Both ends are the same parallel BSP standard, so the only thing that changes is the size; do not swap standards at the same time. If you need to cross to a different thread form as well, add the correct thread adapter rather than forcing a same-standard reducer to do two jobs.