NO FIT FOSTERS

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Keyman62421

Keyman62421

Member
Feb 24, 2017
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Claremont, Illinois, 62421 United States
I'll try to post this so it makes sense. I have several guns, of course all have a foster Male fitting attached some where. I have numerous whips attached to compressors and charging fill gauges. I have 1 FX extended female quick conect fitting ( for impacts) that fits ALL Male fosters. I have others that fit some but not others and some that fit others but not some 🤔 I even bought a couple new extended from Trenier, didn't fit, called and when they checked, none of their's fit. The most common fault is the diameter of Male is larger than female. Some the Male will not fully seat in the oring housing @ base of fitting. Too long. While your opining on this, I place my impact and maverick side by side and try fittings. Some will fit impact but not maverick.

My question is "HUH?"

I've been fighting this for several years! No they are not all AV, HOWERVER I have an AV female and Male that won't fit together. I've tried to figure If bsfp or what ever and or the other was the problem but is is a dominant yet random fit problem. I'd replace them if I could be sure of fits. I MUST check EVERY time I go to range and carry extended fx.

HALP🤬
 
I've had the same problem across multiple male fosters, usually fill probes, but also on a male to male foster.

The issue on all of mine has been that the distance between red lines here is too wide for some female fosters.

fosters.1630500860.jpg


On one of my eaglevision fill probes a buddy machined some material from the shoulder where the green arrow is pointing, carefully keeping the same angle and not removing any material in the thinner neck portion of the foster. 

I've been able to do the same with caveman machining tools on others. Chuck it up in a drill and spin it against a file or emory cloth wrapped around something with a good sharp angle. 

True machining is the best way to do it, but it can be accomplished the redneck way. I'm not saying I recommend the redneck way, as it could get you in trouble if you take too much off the neck area and create a thin spot. 
 
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yup ... what i did that was quite effective is hit them with 600 grit paper .. and the best way to do that is take them off and chuck them in a drill and spin them .. just keep workin it until they fit the tightest female you use well ...

.. to clarify i found 'none' of the wide variety of sourced fittings i have to be 'too wide' as above .. its almost entirely the diameter that makes it difficult to push in, especially deep enough the ring clicks .. every fitting i used i got to operate like butter using the mentioned method with 'zero' issues ..orings cover a multitude of sins so to speak, as long as that ring locks easy and positively ... 
 
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yup ... what i did that was quite effective is hit them with 600 grit paper .. and the best way to do that is take them off and chuck them in a drill and spin them .. just keep workin it until they fit the tightest female you use well ...

.. to clarify i found 'none' of the wide variety of sourced fittings i have to be 'too wide' as above .. its almost entirely the diameter that makes it difficult to push in, especially deep enough the ring clicks .. every fitting i used i got to operate like butter using the mentioned method with 'zero' issues ..orings cover a multitude of sins so to speak, as long as that ring locks easy and positively ...
Click to expand...

My solution as well, EASY and done.
 
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Screenshot_20210901-082532.1630510093.png


On second thought, it's probably more the distance between these red dots than the too wide band that has been the issue. If distance between these two dots is too much, the tip bottoms out and the shoulder is still distal to the locking rings. Removing some of the shoulder as I previously described solves it. 

Just reducing the OD of the band causes some concerns for me. That band is what keeps the female on there, just the tiniest bit too much reduction in diameter of the band and the females gonna go flying. Wonder what the fpe of a 1 ounce? (437 grains) female foster is when it's got 4200psi behind it with a 87cf plenum? Yikes!?!?!
 
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I've had the same problem across multiple male fosters, usually fill probes, but also on a male to male foster.

The issue on all of mine has been that the distance between red lines here is too wide for some female fosters.

fosters.1630500860.jpg


On one of my eaglevision fill probes a buddy machined some material from the shoulder where the green arrow is pointing, carefully keeping the same angle and not removing any material in the thinner neck portion of the foster. 

I've been able to do the same with caveman machining tools on others. Chuck it up in a drill and spin it against a file or emory cloth wrapped around something with a good sharp angle. 

True machining is the best way to do it, but it can be accomplished the redneck way. I'm not saying I recommend the redneck way, as it could get you in trouble if you take too much off the neck area and create a thin spot.
Click to expand...

The only thing I've had to do to any male fosters (so far) is reduce the OD of the area between the red dots shown above, not change the width of that "band" or mess with the shoulder. Certainly wouldn't want to take off too much but if one doesn't go FULL redneck on it(i.e. check fit as you remove a small amount), it seems to have worked for most people. I suppose other dimensions could be off as well but that OD seems to be the common source of mismatch, based on what I've read.
 
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Screenshot_20210901-082532.1630510093.png


On second thought, it's probably more the distance between these red dots than the too wide band that has been the issue. If distance between these two dots is too much, the tip bottoms out and the shoulder is still distal to the locking rings. Removing some of the shoulder as I previously described solves it. 

Just reducing the OD of the band causes some concerns for me. That band is what keeps the female on there, just the tiniest bit too much reduction in diameter of the band and the females gonna go flying. Wonder what the fpe of a 1 ounce? (437 grains) female foster is when it's got 4200psi behind it with a 87cf plenum? Yikes!?!?!
Click to expand...

Remove a tiny bit then check. Not that difficult. 
 
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I got an extended female foster QD from Joe B that didn't fully lock on to a deadhead and it blew out at about 3kpsi (exciting!). Joe usually uses quality USA made fittings, so I poked around the internet looking at these extended female foster QDs. My conclusion - couldn't find any USA made ones, all the pictures look the same, so I bet they all come from the same chinese factory, no matter what brand they are sold under (FX, Saber Tactical, etc).

No more chinese fittings on my HPA gear. USA Foster branded fittings work every time with no fit issues. If I had a fit issue with a male fitting in a new airgun, I wouldn't even blink at swapping it out for a Foster one. Easy fix.
 
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I have been finding that Most Asia Foster fittings are a true 8MM and the rest are around 7.7mm. The Asia females will fit loose on the ones we regularly use 7.7mm, and females of other origin wont fit the Asia males. also of note is the Asia fittings are mostly m10 x1 thread, and the ones we find are 1/8 NPT 27 thread pitch, 1/8 BSP 28 thread pitch, or 1/8 BST at also a 28 thread pitch. I believe the foster fitting that is most used is the Foster 22 (Standard US) but I have yet to find a "true" measurement for these fittings. 

QD-4mm-foster22_DIAG.1631876386.png
 
foster fittings.1631876565.jpg



 
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