Building from Old and Spare Parts 2
Continuing with my previous post, I checked another set of gears which I am considering for my project. These orginally came with the black gearbox and the gears currently being used came with my M4. Why I swithced out these gears I cannot recall.
Sector gear. In terms of weight, it's heavier because of the lack of holes made to lighten it, giving one the impression it is a sturdy gear. In my opinion, it could contribute to extra weight and make it harder to stop when it is rotating. The lack of a sector chip (I forgot to take a shot of the other side) also means there is a possibility of misfeeding when used with a lipoly battery.
Spur gear. The polished finish from sanding surface marks due to the improper shimming and the sector gear when it rotated. One of the earlier mistakes I made when I started out in this hobby was to use the gun without checking to see if the gears were properly shimmed. Except for that, there are no issues. The teeth show no excessive wear and the axles appear straight and parallel.
Bevel gear. The orginal bevel gear my M4 came with had less teeth for the anti-reverse latch grab on to. This version is much better and a lot easier to de-cock manually. I also have a version that comes with ball bearings on the other side of the gear. To be honest, I can't tell if there is a difference in performance whether this gear has ball bearings or not. I do think that using that kind of gear with heavy springs could lead to early wear and eventually misalignment.
Here I have two springs from Guarder, the one on top is an SP 120 and the other an SP110. Both springs have seen extensive use. The SP120 in particular has been used in three AEGs, first the M4 and then my two G3s. The SP110 was originally used the G3A3 because the stock motor wasn't strong enough to handle any spring higher than a 110. Because the 120 has seen so much use, it is no longer straight and this has affected its performance. When I last used this on my RAS, it clocked 380 fps. Not bad for CQB but I was expecting a bit more. On the same gun the 110 clocked at 390 not only because it's a few months "younger", it has remained straight.
Piston body and head. Had I known I had this stashed in my toolbox, I would have not bought the previous unit for the G3A3. This also came with the black gearbox. It has bearings which allows the spring to twist when it is being compressed extending its life and keeping it from twisting the piston body or head. Although it is not clearly shown, the two teeth after the last have been shaved off for better engagement with the sector gear. When I took it apart for this shot I noted that the screw was a bit too tight so I may have to look for a replacement with threads that aren't as sharp.
Cylinder. This came from the G3A3. As you can see, the hole is square and it's location is similar to that of a type 2 found in JG M4s. When I had this paired with an SP 110, it clocked at 410 fps (barrel was a stock 506mm, 6.08 id) on a Guarder chrono. When I tried it with my then new SP120, it clocked at 460 fps , this time using a Madbull chrono. It is relatively soft, as the marks and lines made by the piston head are evident on the inside of the cylinder wall. I don't remeber comparing this to a regular cylinder though I expect to have the same perfomance.
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