Keg post thread confusion

[stever1000]

I'm referencing this website which shows the different thread sizes:
http://www.dresselbrew.com/Keg_Info.htm

I have one cornelious ball lock, and one firestone VI ball lock, however I am having difficulties putting the threads back on properly...

According to the above website, the threads are :

Firestone VI Challenger
Gas 9/16"-18
Liquid 5/8" -18

Cornelius Spartan & Super Champion
Gas 19/32" - 18
Liquid 19/32" - 18

I have two liquid and two gas posts. Two gas posts have the notches on the base, and the two liquid have no notches. To confirm this, the gas disconnect only locks easily on the gas post, confirming I have two of each.

My confusion is this:
all 4 (gas and liquid) posts will easily thread all the way onto the GAS/IN on the Firestone keg.

Both liquid posts will screw onto both threads (GAS/IN and LIQUID/OUT) on the cornelious keg, but neither of the two gas posts will screw onto the cornelious threads.

The website above lists different size threads for the liquid/gas of the firestone, whereas the corny has the same threads for liquid/gas BUT firestone and cornelious have different threads.

What has happened?

To make matters more confusing, I bought 6, cleaned all of them (including dissassembly), sold 2 (both of which held pressure) filled two of mine (both hold pressure and are in the kegerator) and the last 2 got mismatched somehow.

 

[stever1000]

Anyone with more experience have any insight?

 

[johnhenryrolf]

I am a machinist, and am trying to figure out what you've got going on...all I can say is that you (obviously) have some different thread sizes going on, but after reading your question I'm going to have to re-read, and maybe re-read again to figure out what your issue is!? What's your question?

(10 minutes later)...your 9/16" thread is way smaller than all of the others, the 19/32" threads are smaller than the 5/8", but MAY still work, all of the tpi (threads per inch) look to be the same, but you're going to have trouble sealing a bigger female side with a smaller male side. Hope this helps!

 

[day_trippr]

The Cornelius 19/32 threads are larger diameter than both of the Firestone thread sizes, so you were just cross-threading the larger Corny posts over the smaller Firestone threaded risers. If you had actually tried to tighten them down you'd probably have stripped something...

Cheers!

 

[geejay]

The website is correct on the thread sizes. FIrestone not only uses a different size for gas and liquid, but changed it from model to model, so there are 5 or 6 different firestone posts. I recently reconditioned about 40 corny kegs and 79 of the posts were 19/32". The one odd post was on a Corny "Spartan" and used a 5/8 like a Firestone.
You can put a larger post on a smaller fitting, but it won't seal and you might mess up the threads.
More than half of my Corny gas posts are 12 sided. Most of my firestone posts were 6 sided. Most of my firestone posts had Hansen written on the side. My corny posts never have writing.