O-Ring Design/Fit question

Dick,

Look around the net for the Parker Hannifin Seal division web site. They have a O-ring design handbook that has everything in it and more. The printed version is something like 5/8" thick, but they have the PDF version on the web site.

Good luck

V>I am attempting to make a swivel fitting for a hydraulic landing gear

What he said. Plus look around the web site for "o ring university" or something like that. I toured a few months ago, would have saved me abunch of time making mistake many years ago. Leave feed back if you find it (please), I forgot to bookmark it. Kent

surprisingly, i would go look for a good paintball store! most if not all the external lines on those guns are 1/8npt, and i've seen swivels and stainless braided teflon hoses, etc. i know that most of the teflon hoses are rated for hydraulics. also, from my hot rod days, 2 companys called Earls and Aeroquip used to have a lot of the same stuff.

They're called "Banjo Fittings". Used on hydraulic systems on commercial aircraft. I would imagine, too, that Earls or Aeroquip would have them.

Garrett Fulton

What I am looking for is NOT a banjo fitting but a dynamic moving fitting Commercially it is refered to as a Live swivel. I found some fittings Manufactured by Tomkins Industries but the smallest size is

The Parker Manual on O-rings can be found at

Sorry I wasn't of any help in your search. I've seen banjo fittings used on hydraulic plumbing on the landing gear of Boeing, Lockheed, Grumman, Douglas and Airbus for the last 37 years. Figured you could use the same thing, but maybe they don't come in that small of a size.

Garrett Fulton

As far as I can see, 00-5700.pdf is the cover and table of contents. You need to download that and 01-5700.pdf, ..., 11-5700.pdf. This will omit a bit at the end like the back cover. :-)

Ted

Banjo fittings are strictly a static device while swivels are dynamic. A swivel will rotate allowing the hydraulic fluid to pass unimpeded. A banjo fitting will not swivel and when someone tries to make it swivel it spills its contents all over the place.

Best regards, Charles

Charles A. Peavey wrote in article ...

The banjo fittings I'm familiar with do swivel in operation. The drilled through bolt that secures the cylinder to the bulkhead fitting is shouldered at the shank to prevent seating too deep and binding the cylinder. The through bolt is also cross drilled with several ports and grooved for Orings that seat on the inside diameter of each end of the cylinder. I haven't ever seen a banjo fitting retained with what looks like a snap ring as in the Tomkins swivel fitting on an aircraft hydraulic system. Probably just a question of semantics. Here on the flight line, they're called banjo fittings and they swivel in operation. They most assuredly don't spill their contents during swiveling. A dynamic device, not static.

Garrett

Greetings:

Thanks for your reply and an interesting addition to the dialog. I am not sure what jargon is used on flight lines. I am familiar with banjo fittings from an automotive standpoint. Banjo fittings have been in use in the automotive field for many years and are technically called so. The fuel connection on Skinners Union carburators most immediately comes to mind as do the fluid fittings commonly used by Vickers on British brake systems. Perhaps the difference in terms comes from a difference in location since I know in Great Britain they refer to items by quite different names than we do in the "States"

However, in technical literature, and both US and Foriegn sources come to mind, I have always known hydraulic swivels to be just that. As principal engineer and co-owner of Action Mechatronics, Inc (formerly Action Hydraulics, Inc) and a fluid power engineer for over 37 years I have never heard of a swivel being referred to anything other than as a swivel.

All swivel fittings worth buying are designed to be taken apart and rebuilt with new "O" rings. A retainer must be of a type that can be easiloy removed. To allow a swivel of the type you describe where the seals are compressed by a central bolt would be to doom to failure in a very short time since the "O" rings are clamped by the bolt, washer,, banjo body and the body of whatever it is screwed down to. While I do not doubt that there is the possibility of moving a banjo type fitting it is not designed to do so since the clamping force can not be controlled. In a swivel the sealing forces are constant and the only thing that varies is that over the years the body will wear but it will take a very long time. In hydraulic systems using the wrong kind of fitting can be a dreadful mistake and at the very least costly in terms of parts. The wrong fitting in high pressure hydraulic systems (systems over a few hundred psi) can also be deadly.

Best regards, Charles

And probably not familiar with aviation hydraulics which explains the rest of your post.

Charles A. Peavey wrote in article ...

And I'm familiar with "banjo" fittings from an aviation standpoint. That_is_what they're called.

The clamping force is controlled by the shoulder on the through bolt. The Orings are_not_compressed. End play is set up with stainless steel washers at either end of the cylinder and the cylinder rotates freely. The fitting can be disassembled and the Orings replaced and any leakage I've ever seen were due to worn Orings. Tell you what. Next time you come through the airport at Charlotte, NC, go up to one of the USAirways ticket counters. Get the agent to dial ext. 3830 and ask for me by name. I'll come up to your gate, escort you down to the line. We'll find an aircraft that isn't due out anytime soon. We'll go up to the cockpit, turn on the pumps, and go find a hydraulic bay. You can use my flashlight, (I'm on 2nd shift), and stand there and swivel a "banjo" fitting to your heart's content. If it leaks, I'm buying the beer.

Garrett Fulton

I've always been familiar with "banjo" fittings in automotive, in two, three, four, and five port arrangements, and used in brake, fuel, injector, and oil lines They are a fixed in place item, not designed to be used as a live swivel fitting. But I decided to have a quick peek at my Aircraft Spruce catalogue, which is mind you the only one of that type product supply I have. In the section dealing with Fuel Supplies-Primers, ACS shows a sub title and drawing and the following text caption:

quote (verbatim) BANJO FITTING This can be rotated through 360 degrees then tightened and safety locked. Excellent for applications where space was limited. It can really be described as an adjustable 90 degree elbow fitting. P/N 05-29565......................................$52.75

end quote.

There are none of the usual dimensions given, but would appear to have a male 1/4NPT both on the end and on the spud.

Mind you, ACS isn't "big" on hydraulic systems!

Take care.

Brian Laws>