TheSamba.com :: View topic - AN-6 vs AN-8

Sat Aug 06, 2016 12:22 pm

Dale M. wrote: roachdub58 wrote: 74 Thing wrote: I use AN-10 for the oil hoses. Regardless if you use AN-8 or AN-10 make sure you do not use restrictive brass fittings. If you do you should port the restrictive fittings first. Better yet just buy some quality XRP fittings that flow well from the get go and are not restrictive. You still may need to clean up casting flash on the oil cooler mount.

I'm always praising XRP. I've sold thousands of fittings and made/crimped tons of a/c, Teflon brake, oil, hydraulic, and fuel hoses. The quality and consistency are some of the best. Not all fittings are the same. If you were to order a standard XRP -8 NPT to AN adapter fitting, it will be 3/8" NPT. The hole machined through is one size. AN seals on the face, so the size of the hole can vary between manufacturers. If flow is your concern, don't get hardware store fittings or Chinese AN that may have a smaller hole or step machined into it.

Is my perception wrong but isn't the hole in fitting and inside diameter of tube supposed to be the same for "-X" AN fitting you get..

Though AN stood for "ARMY-NAVY" (AN) standard so military machinery all have same fittings so there would never be a supply problem if a replacement fitting was needed.... Some place a few years back the was a military document the specified any AN fitting to be used on military machines....

Also as you increase size of fitting the area of inside almost doubles so a a AN-8 will flow almost double a AN-6 will flow...

Just for giggles...

http://www.diamondfasteners.com/Military-Fasteners/fittings/an-fittings

Dale

Correct, I think the first use was military aircraft engines.

Sat Aug 06, 2016 12:38 pm

An important consideration, is that hose length and fittings do cause restrictions to flow. In other words, if your installation requires 15' of hose, and/or elbows at every end, would be better off using a larger size hose (an-10) than usual.

Sat Aug 06, 2016 1:05 pm

If it's a real AN fitting actually made for military use, you can be pretty sure the machining will be to a certain spec. I've looked through buckets of surplus fittings from military use and they are good with varying color and cosmetic differences.

Then, you have Chinese made fittings that are made for Joe Blow the private consumer and they can be made anyway they want. Someone like XRP can make a performance based fitting that can be different from military spec because they are marketed as a high flow fitting. Nothing guarantees any of these fittings will match each other. Some of the radius machining makes an XRP fitting possibly more expensive and higher flowing than military spec requires. I think they tried to exceed military spec. XRP anodizing/plating is waaaay nicer than real military AN. There are small differences such as leaving a brushed finish or polished finish before anodizing. Cheap fittings have cheap anodizing that changes color with heat too.

You also have JIC spec fittings that are a little different even though they are still a 37 degree flare and basically compatible for what we are using them for, not critical things like aircraft and battleships.

Sat Aug 06, 2016 2:03 pm

roachdub58 wrote: If it's a real AN fitting actually made for military use, you can be pretty sure the machining will be to a certain spec. I've looked through buckets of surplus fittings from military use and they are good with varying color and cosmetic differences.

Then, you have Chinese made fittings that are made for Joe Blow the private consumer and they can be made anyway they want. Someone like XRP can make a performance based fitting that can be different from military spec because they are marketed as a high flow fitting. Nothing guarantees any of these fittings will match each other. Some of the radius machining makes an XRP fitting possibly more expensive and higher flowing than military spec requires. I think they tried to exceed military spec. XRP anodizing/plating is waaaay nicer than real military AN. There are small differences such as leaving a brushed finish or polished finish before anodizing. Cheap fittings have cheap anodizing that changes color with heat too.

You also have JIC spec fittings that are a little different even though they are still a 37 degree flare and basically compatible for what we are using them for, not critical things like aircraft and battleships.

yeah we have aluminium and steel oil fittings, used on both hard and flexi lines, oil, fuel and 3000psi hydraulics... never seen a badly made one, but what the Navy pay for them, i'd hope not either! especial when there flight critical

:)