HoseFitFinder / Every thread and fitting standard

Connect 3/4" BSP tapered (R3/4 / BSPT) to 3/4" BSP parallel (G3/4 / BSPP)

How to join R3/4 and G3/4, and what stops it leaking.

Needs adapter

End A

3/4" BSP tapered (R3/4 / BSPT) (R3/4)

Seals on on the thread flanks with PTFE tape or paste

via adapter

End B

3/4" BSP parallel (G3/4 / BSPP) (G3/4)

Seals on flat washer or bonded seal on the face

Adapter neededR3/4 tapered to G3/4 parallel adapter

Not a direct fit. Joining 3/4" BSP tapered (R3/4 / BSPT) to 3/4" BSP parallel (G3/4 / BSPP) needs a R3/4 tapered to G3/4 parallel adapter.

The adapter to buy

Search Amazon for R3/4 tapered to G3/4 parallel adapteraffiliate search Find R3/4 tapered to G3/4 parallel adapter on eBayaffiliate

An R3/4 tapered male will start into a G3/4 parallel female because the diameters match, but the seal is made differently: the taper seals on the thread, the parallel on a washer. A dedicated adapter, or PTFE tape plus a bonded seal, makes it reliable.

Mixing tapered and parallel BSP is a partial fit that often weeps. Decide which end does the sealing and set it up for that, do not rely on both.

Related connections

3/4" BSP tapered (R3/4 / BSPT)R3/4 3/4" BSP parallel (G3/4 / BSPP)G3/4 Garden Hose Thread (GHT / NH) to 3/4" BSP parallel (G3/4 / BSPP)adapter 1/2" BSP parallel (G1/2 / BSPP) to 3/4" BSP parallel (G3/4 / BSPP)adapter 3/4" BSP parallel (G3/4 / BSPP) to 1" BSP parallel (G1 / BSPP)adapter Male aerator thread (M22 x 1 / 15/16"-27) to 3/4" BSP parallel (G3/4 / BSPP)adapter

Sources: BS 21 / ISO 7 (BSPT tapered pipe threads) · BSP thread dimensions chart (ISO 228 / ISO 7), AmesWeb · ISO 228-1 (G / BSPP parallel pipe threads) · Washing-machine / dishwasher inlet 3/4 BSP connector data