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How do I connect UK BSP beer fittings to a Corny keg rig?
UK beer fittings run on parallel BSP threads that seal on a washer, so bridging them to a flare-based Cornelius rig is about the seal type as much as the thread.
BSP is parallel and seals on a washer
British beer gear leans on BSP threads. The classic UK beer-nut and tail thread is 5/8 inch BSP, and 3/8 inch BSP shank threads also appear. BSP parallel threads, sometimes written G, follow ISO 228 and seal on a washer or O-ring, not on the thread itself.
That is a different sealing principle from the SAE flare on a Cornelius setup, which seals on the coned face, and from NPT, which is tapered and seals on the thread. Knowing which seal you have tells you whether tape helps or hurts.
What a UK shank presents
A UK keg coupler or a font shank typically hands you a 5/8 inch BSP beer nut on a tailpiece. Behind that sits barbed tube or a further BSP thread. Because the beer nut seals on a fibre or nylon washer, you fit a fresh washer rather than wrapping the thread.
On the gas side, UK regulators and couplers vary, so confirm whether your gas port is BSP or a barb before buying an adapter.
Bridging to Cornelius flare
A Cornelius rig usually terminates in 1/4 inch MFL flares and Duotight push-in fittings. To join a UK 5/8 inch BSP tail to that world you use a BSP-to-flare or BSP-to-barb adapter, keeping the washer seal on the BSP side and the flare face seal on the flare side.
Do not put PTFE tape on the flare, and do not rely on tape to fix a leaking BSP washer joint. Replace the washer instead.
Getting the sizes right
Match the BSP size before you buy: 5/8 inch BSP is the common beer nut, while 3/8 inch BSP turns up on smaller shanks. On the Cornelius side, match your flare (1/4 inch MFL or FFL) and your push-in tube OD. Order the adapter that names both ends and you avoid a stack of near-misses.
Get the right fitting
Open the KegFitFinder toolBridge BSP to flare or push-inFind 5/8 BSP beer nut to MFL adapter on eBayaffiliateRelated
Sources: ISO 228 (BSP) thread standard ยท American Homebrewers Association