15. 09. 2018
Based on yours frequently asked questions about the high "price" of ou CNC gearbox V2, we decided, that we will answer you by this article and we do a comparison of two same products. In this case "CNC" gearbox "7075" made by chinese manufacturer againts our CNC milled gearbox made from aircraft dural EN AW 7075. Both of these gearboxes are V2 versions.
We will start with chinese gearbox. This gearbox includes pre-installed ball bearings which means a serious functionality problem with plate selector and fire selector (we made an article about that) and that causes destroying of the plate selector.
Picture n.1 - First suspicious thing is too good looking layer of the anodizing, as you can know from our articles, anodizing process on aicraft dural EN AW 7075 is very difficult and you can see all layer defects on the surface of the material, mostly when material reacts with copper in anodizing bath. There are also no radius cuts in the space of the cylinder, so that is another thing, that needs to fix up.
Picture n.2 - Metal burrs everywhere.
Picture n.3 - Thread holes for the screws have really huge metal burrs and they needs to be removed.
Picture n.4 - There are a lot of inaccuracies in the gearbox, a lot of milling defects and both sides does not fit together very well.
Picture n.5 - The pin of trigget unit spring is pressed in a that is only in matter of time, when this pin will drop out during fire. We also used this method in past, but this solution makes only problems than solution, this solution only brings savings during manufacturing.
Picture n.6 - Pin for tappet plate spring is also pressed in. Space for Hop Up chamber is not cylindrical but with sharp surface. Cylinder to the cube can not go.
Picture n.7 - Metal burrs everywhere. Worst part of this are mostly humped line after milling which gives us a clue, that this is not aircraft dural, because it is can be cutted perfectly, so the surface should be smooth. This looks like a foundry type aluminum. You can image how must the polymer piston feel, when it is moving on this sharp burred surface.
Picture n.8 - Another burrs and inaccuracies.
Picture n.9 - Huge metal burrs everywhere, milling machine also directly misscuts into the product, a lot of edges from inaccurate milling.
Picture n.10 - Inaccurate manufacturing = a visible hole on one side = low strength of the bushing/bearing.
Picture n.11 - Burrs, inaccuracies. Different lines of milling, hitting the material with milling.
Picture n.12 - Space for Hop Up chamber must be cylindric (circle), we can see a rough edge in this case, so fitting the Hop Up chamber would require modifications. All milled parts are made with huge demand on savings what results in low quality. One side of the gearbox has cutted edge, other one somehow.
Picture n.13 - Again, burrs and inaccuracies.
Picture n.14 - Missing trigger stop, that is because of saving on the material and customer gets incomplete products.
Picture n.15 - Gearbox can not be fitted together without movement will because of huge pins for connections. Screwing together also not helps. There is just a visible gap againts light.
We wasn't really sure, that this gearbox is made from aircraft dural, so we asked our partner Scrapmetals Gebeshuber for material analysis. Results were not surprising. This gearbox is not made from aircraft dural, as the manufacturer and seller declares. But it is made from foundry aluminum which has only third of the strength againts our used aircraft dural. We want to say, that manufacturer of these gearboxes deceives the customers and lies about his products. If we count that to that all manufacturing defects and inaccuracies, we do not understand why some people defending this product. Well we can imagine why, because they never had a chance to compare that product to the other one. This products is completely pointless, it is not manufactued well, does not have required strength and mechanical resistance.
The results basically says, that the chinese gearbox is made from 97,93% pure aluminum and other elements have only some tenth of %. This is pure deceiving and cheating of the customer. We would be ashamed honestly if we sell this products to you. So make a picture about comparison of our CNC gearbox V2, which is milled from huge block of aircraft dural EN AW 7075 with more than 3x strength than the chinese gearbox, made from foundry aluminum. Basically we can see, that the typical chinese manufacturer is focused on making with the lowest possible price and selling with highest possible profit, as people say, f*ck with the customer.
We can see from the analysis of the CNC RetroArms gearbox, that it is trully made from declared material EN AW 7075, what is aircraft dural. Chemical formula for EN AW 7075 is AlZnMgCu1,5, so it can be seen, that all of these elements are in standard norm in this material.
CNC RetroArms gearbox V2 is manufactured from huge block of aircraft dural EN AW 7075. For manufacturing we use 2 blocks of this material of almost 2kg weight.
Picture n.16 - Two pieces of aircraft dural EN AW 7075 used for manufacturing of CNC gearbox V2.
Picture n.17 - Look on CNC gearbox V2 manufactured from aircraft dural EN AW 7075.
Picture n.18 - All edges are milled out, no burrs.
Picture n.19 - All edges are milled out by machine.
Picture n.20 - Tappet plate pin is solid part of the gearbox, it can not drop out and thanks to strength material, it can't break.
Picture n.21 - Pin for the trigger switch spring is also part of the gearbox and has same groove as the tappet plate pin, so the spring do not slide off the pin.
Picture n.22 - Guiding line for piston is milled with precision, without any burrs, surface has the best quality and the piston will move freely.
Picture n.23 - Detail of space for trigger switch unit and plate selector. All lines are milled equaly on each other and all edges are milled out.
Picture n.24 - Precise cylindric milled space for Hop Up chamber. Take a look on all edge cutting and quality milled surface.
Picture n.25 - Solid part of gearbox is also trigger stop.
Picture n.26 - Both sides of the gearbox fits perfectly together even without the screws.
Picture n.27 - Space for motor is precisely milled, centered and all edges are milled out.
Picture n.28 - Rear part of the gearbox, where sits QSC spring guide. All edges are milled out perfectly.
RetroArms gearbox has also some clever solutions like protection of wirings againts rubbing, grooves for spring, AOE window and other ones, which we talk about in another article about our new generation of CNC gearboxes V2. These little details like small edge cutting, clean milling work, using high quality material and polymer (very expensive) fluid for milling and preservation makes all added value to our gearboxes. For example our special strentgh torx screws 12.9 with low head also adds to the value of the product.
We tried also i test with sharp knife. We make a cut on the both ones and there was no surprise, that chinese gearbox was much more soft, than the RetroArms one. It is a proof, that chinese gearbox is not manufactured from aircraft dural like our RetroArms ones.
The choice is always on the customer, we just wanted to make a point about questions, why our gearboxes costs little more. In the end it is not true. If we make a point about low quality material and low quality manufacturing process of chinese gearbox, this gearbox should cost much more less. We need to also add needed time for modifications of this chinese gearbox to get it working propeply, mostly shown on pictures number 3 and 12.
