O-ring Size for Walther Fill Adapters?

[Gwhite]

I need to order spares for the team I help coach. They use the same adapter for the AP-20, LP-400 & LP-500. They aren't listed on any of the parts lists I can find. They appear to be ~ 12.8 mm ID x 2.5 mm cross-section.

Does anyone have anything more definitive?

Of course, they don't appear to be the same size as the ones used by any of the other fill adapters we have...

Thanks!

[David M]

part no 2620774 O-Ring ø 12.0x2.5mm
to fit fill adaptor #2771080 200/300 bar kpl.

[Gwhite]

Thanks! The fill adapter part number for the AP20/LP400/LP500 is #2777878, and it's only rated for 200/232 bar.

12 mm is going to be quite a stretch on the ID to fit... I suspect they may use a smaller ring for the 200/300 bar adapter.

The rings are pretty tight. I tried prying one out, but I didn't had a suitable tool handy to do it without damaging the O-ring.

Unless somebody comes up with something, I will risk sacrificing an O-ring to double check the size. I have a list of all the parts in an extensive spare parts kit Walther/Hammerli sells for the AP-20. It includes the #2777878 fill adapter, but they don't include a spare O-ring.

[m1963]

Hello-

We had one Hammerli fill adapter with the original o-ring left. The measurements are OD 17mm x2.5mm

We are using these o-rings from Best fittings to replace them, with a perfect fit-

https://www.bestfittings.co.uk/shop/air ... ng-5-pack/

The photo shows the original on the rule, and the Best fittings o-ring installed. If you stack the Hammerli o-ring on top of the one from Best fittings, they are identical.

It seems to be a standard DIN 300, size 112 o-ring:

http://www.captainoring.com/uploads/4/0 ... achart.pdf

Regards,
m1963

[Gwhite]

Sounds good! Thanks! They must really stretch them to get them in place. That's probably good to prevent the students from popping them loose... I've had numerous instances of students complaining about leaks when filling because they lost their O-ring somewhere long the way. Occasionally, it gets left in the female DIN adapter, and then the next student can't get a fill...

I was a bit surprised that Walther would have used two different sized face seals on their fill adapters, but far weirder things have happened.

For future reference, here's a link to the McMaster Carr 12 mm x 2.5 mm ring: https://www.mcmaster.com/9262K236/

These things are far from standardized. Here's what we've found in the past:

Benelli Kite & Morini: 11.3mm x 2.4mm

Steyr (the big one): 13mm x 2.0mm

Hammerli 480K (Converted to AP40 Clynders): 14mm x 2mm (this is for custom brass fill adapters from Larry Carter)

[David M]

That's probably good to prevent the students from popping them loose...

One trick to retain the O ring is to use two or three small dabs of super glue on first install.
Put a drop on a plastic bag and dab a toothpick/match in glue then dab adaptor.
Every little bit helps...

[Gwhite]

That's probably good to prevent the students from popping them loose...

One trick to retain the O ring is to use two or three small dabs of super glue on first install.
Put a drop on a plastic bag and dab a toothpick/match in glue then dab adaptor.
Every little bit helps...

That might work nicely the first time, but then you have to clean the residue off carefully the next time you replace the O-ring. If it was just me maintaining things, that might work, but with several other coaches, one of them is likely to miss that step in a rush & then you've got a problem. Worse case scenario is that somebody decides to clean it out with a sharp implement, and then we're really in trouble...

I've had to make a special tool for hammering out dented O-ring seats in adapters that have been dropped on the business end... Part of my job description is not blowing a gasket when a student destroys part of an expensive pistol in a moment of clumsiness, or due to lack of mechanical savvy. I've already had to rethread a Pardini SP grip bolt this week after a student had thoroughly cross-threaded it.

[David M]

Acetone does the job.

[Gwhite]

True, but the adapters I'm concerned about are in our travel kit for away matches. That makes having acetone handy a bit tricky.

At least for the Walther/Hammerli adapter, the O-rings appear tight enough that we aren't likely to have one come loose. I may investigate using slightly "wrong" sized O-rings in some of the other adapters to achieve the same effect.