Not a direct fit. Joining 4 inch camlock coupling to 4" BSP tapered (R4 / BSPT) needs a 4 inch camlock to R4 threaded adapter. Sealing method, the real-world trap, and the exact part to use.
Updated 05 September 2026.
Connect 4 inch camlock coupling to 4" BSP tapered (R4 / BSPT)
How to join 4" camlock (A-A-59326) and R4, and what stops it leaking.
Not a direct fit. Joining 4 inch camlock coupling to 4" BSP tapered (R4 / BSPT) needs a 4 inch camlock to R4 threaded adapter.
The part to buy
A 4 inch cam-and-groove coupling has no thread of its own, so it reaches a R4 (tapered BSP (BSPT)) port through a same-size threaded camlock adapter: a Type A male adapter or a threaded coupler carrying the R4 thread on its back. That thread is a tapered, 55 degree form of 113.03 mm major diameter at 11 threads per inch and seals on the thread flanks with PTFE tape or paste; the cam end then mates to its opposite 4 inch camlock half.
The 4 inch cam profile and the R4 thread are two separate choices. A correct R4 back thread still leaves you with the wrong front if the half you mate to is not the matching 4 inch cam type, so confirm both the size and the A-to-F type before buying.
Related connections
Questions and answers
Connect 4 inch camlock coupling to 4" BSP tapered (R4 / BSPT)?
Not a direct fit. Joining 4 inch camlock coupling to 4" BSP tapered (R4 / BSPT) needs a 4 inch camlock to R4 threaded adapter.