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bjorn

EB CNC 7075 Gearbox

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Nothing long, since I could not find a review on this item when the purchasing I thought I would write one myself.

 

First impression - simple cardboard box with the words "fine steel" on it, although it really is very lightweight aluminium as stated on Ebaybanned webpage.

 

cncgearbox001gx9.jpg

 

Next just some pictures from the gearbox itself...

 

cncgearbox002qk6.jpg

 

cncgearbox003nd8.jpg

 

Notice the strange forging? marks at the and of the cylinder area inside the gearbox? Can anyone verify for sure what they are. As in if this gearbox is forged and then CNC-d or something else? Also what kind of strength comparison can I expect from this when compared to regular die-cast gearboxes such as G&P or G&G. In the cold?

 

cncgearbox004ta6.jpg

 

 

More coming later tomorrow when I should be able to get to installing Element 300% gears in it with M120 spring and other Marui M4 parts.

 

Stay tuned,

 

Bjorn

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In all likeliness this, along with almost every other "CNC" part in Airsoft, has been machined from a rough cast. Machining from Billet is ludicrously expensive and generally not always worth it.

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image00006wq9.jpg

 

Sorry for the bad image quality.

 

Overall - everything fits in the gearbox nicely, no problem when installing, only the Element 300% gears make a lot of noise.

 

Atm M100 spring in there, shoots 112-114m/s. Ok ROF.

 

 

If anything new happens, I will post it here.

 

Bjorn

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In all likeliness this, along with almost every other "CNC" part in Airsoft, has been machined from a rough cast. Machining from Billet is ludicrously expensive and generally not always worth it.

Can't speak for other manufacturers... but any part manufactured by DYTac that is stated as being CNCed is in fact started off from Billet. I've personally seen it go from Billet to end product. Totally OT, I'm just saying that there are definite exceptions to the rule. As for this "CNC" gearbox, I'm pretty sure it started from a rough casting.

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Can't speak for other manufacturers... but any part manufactured by DYTac that is stated as being CNCed is in fact started off from Billet. I've personally seen it go from Billet to end product. Totally OT, I'm just saying that there are definite exceptions to the rule. As for this "CNC" gearbox, I'm pretty sure it started from a rough casting.

 

Strength wise how does a rough cast compare to a billet?

 

B.

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Not as strong. Casting is the same process they use for potmetal gearboxes, and which are notorious for snapping.

 

If they cast it out of steel, and then machine it, that would be better. 7075 aluminum is great, *same stuff they used in M16s*, but I don't know how much stronger it is compared to potmetal, as it isn't forged or presumably heat treated.

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Can't speak for other manufacturers... but any part manufactured by DYTac that is stated as being CNCed is in fact started off from Billet. I've personally seen it go from Billet to end product. Totally OT, I'm just saying that there are definite exceptions to the rule. As for this "CNC" gearbox, I'm pretty sure it started from a rough casting.

 

Fair enough, but they're an exception. Even the more expensive, reputable brands do this: Sheriff and SD, for example, CNC their slides from a casting, not billet.

 

To be honest, in most cases it really doesn't matter. Yes, from billet is stronger, but in machined from casting is strong enough for airsoft uses 90% of the time.

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