Why do I need to upgrade (or not) - with explanations!

[ILLusion]

Good find. Copper is still softer than steel and harder than brass. Those bushings aren't pure copper though. It's an alloy of some sort and I'm pretty sure it's alloyed to make it tougher and harder than raw copper.

The ICS copper bushings, (like most metal bushings) are manufactured with a sintered process. The process makes the material tougher than in it's raw form and it allows the manufacturer to impregnate the metal with oil.

As a result, when heat is built up due to friction, the metal will "sweat" oil. These are the bushings that are also called "oilless" bushings. I personally prefer these over CNC machined bushings, even if it has "oil channels."

[Agit-Prop]

They're probably "bearing bronze"

[ILLusion]

Is that a "special" sintering powder mix of Cu & tin specifically for bearing use?

[Agit-Prop]

Originally Posted by [url=http://www.tribology-abc.com/abc/sinter.htm

this site[/url]]Porous bearings are manufactured by sintering, e.g. powder of the material components is pressed together at high temperature and high pressure. Despite of the powder is melted together capillary channels remain resulting in a porous material. By impregnation of the channels with liquid or solid lubricants, bearing materials acquires that are lubricated for life, they have not to be lubricated during lifetime. As a fact of the capillary channels porous materials are bros and sensitive for cracks.

Examples of sintered porous bearing materials are the ceramic materials, carbon brushes of electric drives, porous bronze bearing bushes, aluminum matrix composites consisting of a mixture of aluminum powder and ceramic granules and sintered polymers.

The most widely used type of porous bearing in consumer apparatus is a porous bronze consisting of 90% bronze, 10% tin and often some addition of graphite and lead to improve dry running properties. Furthermore a frequent use is made of porous iron bearings, which can take up a higher bearing load but have a lower permissible speed of the shaft in the bearing.

Lubrication regime: About 10 to 35% of the porous material consists of lubricant impregnated channels. As a consequence of the porous bearing surface a sufficient hydrodynamic pressure distribution to avoid mechanical contact between shaft and bush as in solid bearings cannot be created. The pressure build up forces the oil into to pores of the loaded part of the bearing. Then the oil flow to the unloaded section of the porous bearing and replenish the gab [Morgan, 1957]. The type of lubrication that occurs can be assessed by determining the so-called Stribeck curve, which gives the relation between the friction and the shaft speed. Depending on rotational speed and load porous bearings almost invariably operate in the region of mixed lubrication.

It could be a mix of bronze and PTFE or graphite powders

[ILLusion]

hmm... interesting indeed.

Prometheus and Systema both have oilless bushings that have a bronzish colouring to it as well.

[Agit-Prop]

Bronze is used for many applications including valve guides in automotive engines.

[eggman51]

Other relavant good technical info here:
http://filairsoft.com/airsoft124.htm

Eamonn aka eggman

[lamlok]

In HK, the mainstream Mech box mod is to use 8mm bearings for high powered guns.
The large diameter bearing gives both sturctural and friction advantages. Is it common to see guns in excess of 500ft/sec while having 25+ shot/sec.
Of course during the mod, the slightest misalignment will totally ruin the gearbox. I've seen too many DIY failure. Only the most experienced gunsimth will be able to perform such mod.

[BC_K]

Originally Posted by lamlok

In HK, the mainstream Mech box mod is to use 8mm bearings for high powered guns.
The large diameter bearing gives both sturctural and friction advantages. Is it common to see guns in excess of 500ft/sec while having 25+ shot/sec.
Of course during the mod, the slightest misalignment will totally ruin the gearbox. I've seen too many DIY failure. Only the most experienced gunsimth will be able to perform such mod.

Congrat's on diggin up a thread that has been dead for half a year +.

We won't have such a problem cause we DON'T use AEG's that shoot 500fps+.

Welcome to asc, try not to awaken too many threads that are dead. :wink:

[nic_s]

Originally Posted by lamlok

500ft/sec while having 25+ shot/sec.

I'm really sorry for resurrecting this thread, but I gotta ask, am I the only one shocked at hearing 500fps @1,500 RPM? Holy shit, I had no idea an AEG was capable of that. I mean, never mind strong internals, you'd have to hook up a freaking car battery to get numbers like that!

[Nocturnal]

i have seen a video of an AEG shooting a watermelon in half a LOOOONG time ago.
i dont know what battery they used or upgrades.. but i would not want to be at the other end of that muzzle.

[Gryphon]

Holy thread revival, Batman!

Can anyone provide a general list of velocities at which point you ought to start thinking about durability upgrades, and for which part? For instance, obviously a stock or slightly hotter gun seems to run just fine with stock internals. However let's say you wanted to push your AEG to 340, 360, or 380 fps. At what point does it become prudent to install new parts to avoid accellerated wear, bearing in mind that cost is always a factor? No point in spending $100 on new parts if you don't need them.

I suppose it also depends on gearbox construction, because my CA249 box is decidedly stronger than the Version 2 in my M15A4. However some rough starting points would be of tremendous assistance. Thanks!

[mouse]

Woop, Thread revival so hopefully Shuridys get his or her answer, and this thread had been an awsome guide to upgrading my m4!

[Greylocks]

The honest answer is actually pretty dumb sounding; the moment you upgrade the power, you must upgreade the durability.
The guns are designed for their 'stock' power. Anything more is your problem.

[bigbiscuit]

you didn't really explain whether to upgrade right away or not though..just what parts to upgrade and such, good article though, props to that