VFC AEG Mk18 mod1 High Cycle Custom: Gearbox Edition

NowLast time I did a brief review and disassembly.Therefore, we will proceed with determining the direction of customization and selecting the parts.

So, let's start by considering the direction of the customization.

Customization direction and selection of custom parts

First, we determine the target performance level.

There doesn't seem to be anything wrong with it right out of the box, so I'll focus on improving its basic performance.

We select and procure parts based on the target. The procured parts are as follows:

I bought Bellhammer's extreme pressure grease.

This time, I became interested in brushless motors rather than electronic triggers, so I bought one.

I prefer radial ball bearings for gears, so Super Shooter is my only choice.

I chose the rest based on my own preferences.

The plan is to increase the cycle rate with a motor and high-speed gears, and to improve durability, use a reinforced piston and a polymer piston head.

Furthermore, the entire electrical system will be reinforced and rebuilt. This will involve thicker wiring, the addition of fuses, and the use of T-type connectors.

Customization of the gearbox

First, we'll prepare the electrical system.

I've already polished the movable parts of the gearbox without taking any photos this time. Sorry about that.

Electrical system creation

First, I'm going to change all the electrical components, which I hate.

First, remove the original wiring from the switch. To be safe, disassemble the switch and melt the solder on the electrodes. You could also try cutting the solder with wire cutters.

Next, cut the 1.25 sq wire to the same length as the original wire, or slightly longer, and solder it to the switch.

To avoid confusion about which wire goes where, I'll put red heat shrink tubing on the positive terminal and black heat shrink tubing on the negative terminal. (Don't shrink them yet).

I'll temporarily run the wiring through the gearbox, assemble the motor and grip, and visualize how to attach the motor terminals.

Also, it seems that brushless motors won't fit into the grips of some models without modification, but they seem to work fine with VFC's genuine grips.

Check the wiring inside the gearbox.

Check the wiring inside the grip.

The wiring layout to the motor should be the same as the original. The top wire in the picture is for the negative terminal (-) and the bottom wire is for the positive terminal (+).

Otherwise, the lid won't close properly, or the lid and wires will interfere with each other, preventing you from positioning the motor correctly.

Then, attach faston terminals to the wiring.

Next, install a fuse in the wiring.

Attach the faston terminal to the positive side wherever you like.

The leftmost terminal is intentionally installed in reverse. (The terminal is size 110.)

Next, install the fuse and protect it with heat shrink tubing. (Blade 30A)

Attach a T-type connector to the wire extending from the fuse.

All that's left is to attach protective tubing to any areas that might interfere with the gearbox, and then the wiring is complete.

Incidentally, the reason we're not using electronic components like FETs this time is because we're using a brushless motor. I'll explain this in more detail in another section, but brushless motors, by their very nature, require control over the electrical polarity, so they have a control board attached to them.

The motor's control signals and those of additional components such as FETs, SBDs, and FCUs can conflict, causing errors. Therefore, caution is necessary when adding additional electronic components.

Since the control board also serves as a substitute for FETs, we don't need FETs or SBDs this time.

Details on how FETs work and how to wire them can be found here.

Switch customization

Next, install the short-stroke switch into the gearbox and check for any wiring issues. (Also install the cutoff lever.)

The Stinger's short-stroke switch does not have electrodes, so you will need to remove the electrodes from the original switch and swap them in.

We will make a switch.

We'll temporarily assemble the switch on the gearbox side.

Install the short-stroke switch and check it. At this time, it's a good idea to install the cutoff lever and check the cutoff function as well.

Once the switch is assembled, connect the battery and motor and test it.

This test will include both semi-automatic and full-automatic shots.

If there are no abnormalities, the motor will run continuously at full power. In the case of semi-automatic mode, move the cutoff switch to check if the motor stops.

Also, you can adjust the trigger stroke here.

I attached 1mm Tamiya plastic sheet to the gearbox and adjusted it by filing it down.

We also adjust the spread of the switch terminals.

Detailed instructions on how to install the short-stroke switch are provided by Mr. Daimon of Stinger, the manufacturer and distributor, so I will leave the details to him.

Gear preparation

Next, we'll prepare the gears.

First, let's examine the gears.

There are no burrs or anything, so it looks like it can be used as is.

However, since we're aiming for a rate of fire of over 25 rounds per second this time, sector cutting will be essential.

When KRISS VECTORI attached a diamond cutter to my wife's rotary tool and cut the gears like this.

After thinking about it for about 10 seconds, I'll go with a safe setting: cut 3 pieces, 2 on the pull side and 1 on the release side.

When purchasing a diamond cutter, please pay attention to the shank diameter of your existing rotary tool. If you choose the wrong size, it will not fit.

• Diamond cutter, shank diameter 2.35mm
It's very useful for machining iron-based parts such as gears. A hard diamond is recommended if possible.

Mini vise
It's inexpensive and versatile.

In my setup, I can process one gear in about 5 minutes. I finish the cut gear surface with a rotary tool (using a tungsten bit).

Tungsten bit for rotary tool, shank diameter 2.35mm
Tungsten, the second hardest material after diamond, is recommended considering the price. It cuts very effectively.

It's not a very neat finish, but as long as it doesn't come into contact with the piston teeth, it'll be fine, so I'll go with this.

Check the tappet plate

Next, let's compare the shape of the tappet with that of the original part.

Actually, I had prepared the Ronex tappet plate as a spare in case the original tappet plate broke, but this time, the shape of the gear cam (bearing part) and the blades seemed to be a good match, so I decided to use it.

Checking the nozzle position

It looks like the nozzle on the Ronex will stick out a little further. I'll temporarily assemble the tappet, nozzle, and chamber to check for stumbling, hop-up, and feeding.

Nozzle adjustment

This is where we decided on the nozzle length for the retro design.

Experimental results showed that even when the nozzle was extended beyond the original length, it interfered with the gasket opening and wouldn't go in, so I shortened it to the same length as the original, approximately 21.2mm. (I wanted to use the custom nozzle since I had already prepared it.)

I prefer the retro shape of the nozzle tip.

AOE adjustments

Next, we will adjust the AOE (Area of ​​Effect).

First, let's assemble the piston.

The weight around the piston is 26g. This is about the same as Tokyo Marui's, so I'll leave it at that. If it exceeds 30g, I'll remove the thrust bearing or cut out some material to reduce the weight.

Assemble the gears, cylinder, and cylinder head, then check the angle of error (AOE) and ensure that the cut gear bottom does not interfere with the rack.

At the same time, check for play in the cylinder and gearbox.

AOE confirmation

Checking for gear interference

The interference with the machined tooth root was OK, and the cylinder play was OK, but the crucial AOE (Angle of Engagement) was not engaging properly, so I cut out two pieces of the usual 1mm thick Haneite rubber and attached them to the cylinder head with super glue.

Also, since the third tooth of the cylinder rack and the teeth of the sector are close together, we will slightly shave down the teeth of the rack.

While we're at it, we'll add a chamfer to the rear end of the cylinder. It's a little trick to prevent the spring from getting caught.

Now let's check AOE again.

That was a good hit.

Checking for gear interference

There is about 2mm of clearance, so it's OK.

feel well.

Gearbox modification

Next, to prevent cracking, I'll use a rotary tool to round off the four corners of the window on the gearbox casing (just a little).

Next, sand the surfaces where the moving parts inside the gearbox move using #1000 grit sandpaper.

Now, scrub the parts thoroughly with a mild detergent and let them dry.

Safety adjustment

Next, adjust the safety on the switch that still needs adjustment.

I attach a 1mm plastic sheet to the stopper part of the trigger's safety rod and adjust it by filing it down.

By the way, when assembling the trigger, slightly bending the trigger spring towards the gearbox will make assembly a little easier.

Although it's only two or three lines of text so far, the adjustment range is very precise, and it took about four hours.

I'm extremely tired.

Gear bonding

Now that the preparation is done, I'll attach the sector gear bolts with super strong adhesive.

シム調整

Next, we'll adjust the shims based on the bevel gear, as usual.

Assemble the grip and bevel gear into the gearbox and measure the gap of the bevel gear.

Here are the measurement results.

The Sim I chose

Here are the details of my shim adjustment method, which is my own approach.

I tightened the bolts on the gearbox for a test assembly, and when I rotated the gears by hand, the sound and movement were smooth, so it's OK.

I've finally finished the preparation.

All that's left is to assemble it.

This time, I'll be using Bellhammer's extreme pressure grease where high-viscosity grease would normally be applied, and GAW's extreme pressure grease where silicone grease would normally be applied.

Since durability is a priority, I apply a slightly generous amount.

Bellhammer No. 2 Gold Grease
This is a classic, top-quality grease. No. 2 has the same ingredients as No. 0 but with a higher viscosity. I primarily use it for metal-to-metal connections.

GAW G-GREASE
This is a standard grease. It has a lower viscosity compared to the Bellhammer Gold series, so I use it inside the cylinders of both electric and airsoft guns. It's a bit pricey, but the quantity is large, so in the end, it doesn't feel overpriced.

The gearbox is finally complete.

By the way, having something like the red clip shown in the picture is helpful when assembling it.

• Gearbox Installation Kit
This might be useful for those who aren't used to closing the gearbox. You can manage without it, though.

Since this is getting a bit long, the assembly from the chamber onwards will be...I'll do it next time.

VFC MK18 mod.1 AEG Full Metal Tan Color (Officially Licensed Version, JP Version)
This is the main article. It's also available in black in addition to tan.

The VFC Mk18 mod.1 has a 10.3-inch barrel, but the RIS2's 14.5-inch barrel is also cool and highly recommended.

VFC VR16 RISⅡ Daniel Defense
The engraving is different, and the internal components have been slightly upgraded. The link is for the 14.5-inch tan color.