Author Topic: Cradle Billet Box 6061 CNC V2 gearbox  (Read 3363 times)

Offline nukeduster

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Cradle Billet Box 6061 CNC V2 gearbox
« on: November 24, 2013, 02:42:09 PM »
Hey everyone, I received my Cradle Billet Box gearbox the other day, and started assembly on it, with the idea of building a high performance G3 sniper rifle for an upcoming sniper event next month. The goal is 550fps with .25g. The build will be completed next weekend with durability & stress tests to follow.

As it is in its packaging:

Once I took it out of its box, my first impression that I had was that this thing was incredibly light. So much so I decided to take out my scale and measure it vs a lonex shell I had laying around.

Lonex (without bushings or selector plate attached):

Cradle (WITH bushings and selector plate attached).

Also note, that the gearbox indicates the torque ratings of the fasteners for the shell. Also, the windows come pre-radiused.

It's so much lighter, that I decided to start adding components to the gearbox until I could get it to weigh in the same as a bone stock, completely empty lonex shell. To get there, I added lonex 8mm bearings, siegetek 20:1s, DA 14.5 steel teeth piston (not lightened) and polycarb piston head with ball bearings, SHS cylinder and DA cylinder head with sorbo attached, lonex tappet plate, lonex G3 nozzle. Also had all shims to shim properly, a steel MP5 trigger, and a SHS trigger assembly.

Basically, an entire complete gearbox minus wiring, a spring, and a spring guide.

Some interesting little features:

A small cut-out in the gearbox shell that keeps your trigger spring in place so that your trigger does not move about when taking the gearbox apart:

Two small orientation windows that show your piston alignment once your box is sealed up, allowing you to make sure that your piston is sitting correctly in the guide rails.

The cut out at the bottom is to allow larger gauge wire to be used in the gearbox shell, as well as having a small tab protruding outward to keep the wiring retained in position so that it doesn't get cut up by your motor. The window above it, next to the shaft hole of your anti reversal latch is to allow the decompression of the gearbox's spring.

So, there are a lot of strong points to the gearbox, but what about weaknesses?

Honestly, they're more anal retentive gripes but they're worth pointing out.

1. No quick change spring guide. To some this is a plus, since having a quick change spring guide could weaken the rear of the gearbox (which matters since you're going to be using a gearbox like this in stressful builds), add weight and complexity, and add a proprietary part, and for many v2 builds isn't even useful.

2. It uses imperial not metric fasteners throughout. It's not like they're hard to track down if you need replacements but it's worth pointing out for those of you who start throwing metric hex's at the fasteners and start stripping them out.

3. Extra reinforcement material inside the shell which precludes the ability to mount a mosfet internally. It is completely safe to remove this extra material if you wish to install one internally, it just adds extra work for the installer.

Stress tests and final thoughts will follow in a few weeks as I put this gearbox through its paces.