# Ball lock and pin lock keg posts and 5 gal Cornelius keg: post threads, wrench sizes, keg height and diameter

> What thread and wrench size is a ball lock keg post, and how big is a corny keg?

- Category: Tri-clamp & pipe › Pipe, tube & threads
- Kind: Standard part
- Basis: Published post-thread reference (HomebrewFinds), Wikipedia (Cornelius keg), retailer listings (Kegoutlet, Homebrewing.org); numbers only
- Page: https://xemstudio.com/objects/keg-posts-and-cornelius-kegs/ · JSON: https://xemstudio.com/api/geometry?object=keg-posts-and-cornelius-kegs · Plain text: https://xemstudio.com/objects/keg-posts-and-cornelius-kegs/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- The common post thread is NOT 7/16-20. Cornelius and AEB kegs use 19/32-18 on both posts; Firestone and John Wood kegs usually use 9/16-18 (Wikipedia: Cornelius 19/32 in 18 TPI, Firestone/John Wood 9/16 in 18 TPI). 7/16-20 is the 1/4 in SAE flare / AN -4 thread, which is what a flare-nut gas or beer line screws onto; it is not the post.
- Two wrench sizes cover nearly all ball lock posts, 11/16 in and 7/8 in (6- or 12-point); pin lock posts take 13/16 in and need a notched socket.
- Ball lock and pin lock differ by the poppet and connector, not by the post thread: ball lock gas and liquid posts are the same thread and are told apart by the connector, pin lock by 2 pins (gas) or 3 pins (liquid).
- A 5 gal Cornelius-style ball lock keg is 8.5 in (216 mm) diameter and 25 in (635 mm) tall in maker listings; the pin lock is 9 in (229 mm) by 23 in (584 mm). Wikipedia lists 24.75 in for the ball lock and 8.5 in / 9 in diameters. Makers vary by about an inch, so measure your keg before building a kegerator.
- Not published by any maker we could read, so left out (no file): post outside diameter and height, poppet size, post o-ring sizes, lid opening. KegLand lists only a 20 mm long 1/4 in BSP tail on its welded post, and retail pages give no AS568 size for post o-rings.

## Sizes

| keg / post | gas post thread (TPI 18) | liquid post thread (TPI 18) | post wrench (hex) |
|---|---|---|---|
| Cornelius ball lock (Pepsi style) | 19/32-18 | 19/32-18 | 11/16 or 7/8 (6- or 12-point) |
| Cornelius pin lock (Coca-Cola style) | 19/32-18 (2 pin) | 19/32-18 (3 pin) | 13/16 (notched socket) |
| AEB ball lock | 19/32-18 | 19/32-18 | same as Cornelius |
| Firestone / John Wood ball lock (V, VI, Super Challenger) | 9/16-18 | 9/16-18 | - |
| Firestone / John Wood pin lock (A, R) | 9/16-18 (2 pin) | 9/16-18 (3 pin) | - |
| Firestone Challenger (racetrack) | 11/16-18 | 3/4-18 | - |

## Where the files are

- HomebrewFinds: [Homebrew keg post thread size reference](https://homebrewfinds.com/homebrew-keg-post-thread-size-reference) — web — Publisher's page; dimensions are facts
- HomebrewFinds: [Homebrew keg post sizes, ball lock and pin lock](https://www.homebrewfinds.com/homebrew-keg-post-sizes-ball-lock-pin-locks/) — web — Publisher's page; dimensions are facts
- Wikipedia: [Cornelius keg](https://en.wikipedia.org/wiki/Cornelius_keg) — web — Publisher's page; dimensions are facts
- Kegoutlet: [Cornelius kegs (ball lock 25 x 8.5 in, pin lock 23 x 9 in)](https://www.kegoutlet.com/cornelius-kegs.html) — web — Publisher's page; dimensions are facts
- Homebrewing.org (AIH): [New 5 gallon corny keg, ball lock](https://homebrewing.org/products/aih-new-5-gallon-corny-keg-ball-lock) — web — Publisher's page; dimensions are facts
- KegLand: [Ball lock post with 1/4 in bulkhead (20 mm thread)](https://www.kegland.com.au/ball-lock-post-with-1-4-inch-bulkhead-assembly-gas.html) — web — Publisher's page; dimensions are facts

## Questions

**What size is a ball lock keg post thread?**

19/32 in, 18 TPI on Cornelius and AEB kegs; 9/16 in, 18 TPI on most Firestone and John Wood kegs. It is not 7/16-20.

**How tall is a 5 gal ball lock keg?**

About 25 in (635 mm) tall and 8.5 in (216 mm) in diameter in maker listings; Wikipedia gives 24.75 in.

## Fits with

- [Push-fit fitting envelopes: 4 / 6 / 8 mm tube, G1/8 and G1/4 thread stubs](https://xemstudio.com/objects/push-fit-fittings/)
- [AS568 O-rings: all 349 standard sizes, -001 to -475](https://xemstudio.com/objects/as568-o-rings/)
- [Tri-clamp × hose barb adapters (14MPHR style): ½ to 4 in clamp, ¼ to 4 in hose](https://xemstudio.com/objects/tri-clamp-hose-barb-adapters/)
- [Hose barbs for 2, 3, 4, 6 and 8 mm ID tube](https://xemstudio.com/objects/hose-barbs/)