Pin-lock quick disconnect (pin-lock QD, MFL or barb tail)
Where pin-lock QD, MFL or barb tail is used, its real dimensions, and how to connect it to other keg fittings.
Published dimensions
- Designation
- pin-lock QD, MFL or barb tail
- Size / thread
- locates on the post pins; tail is 1/4" MFL (7/16-20 UNF) or a 1/4"/5/16" barb
- Fitting form
- notched quick disconnect
- Seals on
- O-ring seals over the post; the tail seals by flare or clamp
- Rating / role
- the pin-lock keg connector; taller than a ball-lock QD
Used on: pin-lock corny kegs (Cornelius and Firestone pin-lock); gas has two pins, liquid has three.
A pin-lock disconnect drops over the post and locks against its pins, so like the ball-lock it never uses the post thread. The gas disconnect clears two pins and the liquid one clears three, which is what stops you swapping them. The tail choice, MFL or barb, is the same decision as on a ball-lock.
Flare fittings seal on the 45 degree flare face and must never be taped. Push-in fittings seal on an O-ring against the tube wall and need the tube cut square. Barbs seal under a worm clamp. Getting the sealing method right matters more than the thread label, because most homebrew leaks are a taped flare or an unclamped barb.
Connect this fitting
Sources: Keg Outlet corny keg disconnects (ball lock and pin lock, MFL/barb tails) ยท DraftMag ball lock vs pin lock disconnect comparison