Laser Cut M-6 Carnifex Rubber Band Gun From Mass Effect

Ever since I was a kid I have always wanted a rubber band gun. Growing up, my parents would never buy me one because they were afraid I would hurt myself. Now that I'm an adult, I'm old enough to make my own! My urge to own one started when I walked down a toy store with my girlfriend to browse around, and saw the rubber band guns on sale, which were not cheap!

So, since I work at the tool shop in my college I'm attending, I decided to make my own rubber band gun. As an avid Mass Effect fan, I decided this would be a great opportunity to make one based on it. Not only is it a fun toy, but also a great prop for fans! Big shout out to the YouTube user: RBguns for his designs and free plans for his rubber band guns. Using the similar mechanism RBguns used for his M-9 rubber band gun, I designed the M-6 Carnifex around it. Instead of hand cutting all the parts like RBguns did, I used the laser cutter I have access to on campus to cut all the parts out, along with etching the parts for the extra detail!

And following with RBguns' style, I will be giving out the laser cut files for free in this tutorial! So if you want to make your own M-6 Carnifex, come on through!

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If you like this tutorial as much as I did taking the time to make it, please consider taking the time in voting for me in the Epilog contest and Halloween Prop contest as well! This is my first tutorial, so please, any and all constructive criticism will be appreciated.

Step 1: Gather Your References and Supplies

To start, I would recommend going online and looking up some images to reference the gun if you were making this from scratch and to just get a feel of what it would look like from different angles.

Supplies:

Three sheets of 12"x 24" x 1/8" (or 3mm) plywood (I use Baltic Birch from my local hardwood store, but you can get the sheet size from Michaels)
1/8" wooden dowel rod
#4 x 3/4" flat head wood screws
Small rubber bands (I just buy the assorted size)
Regular size rubber bands (I just buy the assorted size)
Wood Glue
Wood Stain (Optional)

Tools Needed

Sand paper (various grits from 220 to however high you wish to go)
Utility knife (in case you need to cut the laser cut parts out)
Glue Spreader (optional, or just you a stick, a card, your finger, etc)
Laser Cutter (technically you can print them out and cut them by hand if you want)
Adobe Illustrator (or an open source program similar)

Step 2: Get the Laser Cut File!

Now, if you were to make this from scratch, you would download a side image of the gun, blow it up full size and trace it with your vector editing program (Illustrator or other open source programs.) However, I have already done it for you all, so just download it! Also, download the layout pattern so you know which parts stack up on where.

The parts to laser cut are separated into three sheets because I usually work in 12" x 24" sheets of plywood (easier to break down from a 5' x 5' sheet of plywood from the lumber yard.)

Also, as requested by a member who left a comment to recommend it, I also converted the files to DXF. Hopefully they will still be in the right scale.!

Step 3: Cut the Parts Out!

With the files on hand, go ahead and cut them out on the laser cutter you will be using. As everyone will probably have a different set up for their laser cutter, make the changes you need with Illustrator or other open source program.

The way I have my file set up is for the laser cutter I have at my college campus, which is a Universal Laser Systems: Model PLS6.75. Because of this model, my laser cut files are designed with these parameters:

Red lines: The laser cutter will cut these lines
Black filled in areas: The laser cutter will raster (or etch) the area
All cut lines have to be hairline (.001 in)

Depending on how well your laser cutter cuts, you may need your utility knife to pop them out.

IMPORTANT!!!!!!!!!!!!!!!!!!!!!!!!!

MAKE SURE YOU SAVE THE LITTLE BITS CUT OUT FROM THE MOST TOP PANEL'S. YOU WILL NEED THOSE SMALL CIRCLES AND ROUNDED RECTANGULAR SHAPED PARTS TO GLUE BACK ON.

Step 4: Glue Up the Body Side

For the body, make use of the template given from the previous step to reference with parts. The internal parts are practically the same, except a couple of parts: the top parts where the sights are.

Take your time and glue them properly. After the internal structure is done, flip it over and start building up the outside layers. Again, reference the template for help. Use a spreader to ensure proper coverage of your parts. You can either use an actual glue spreader, a regular piece of flat material, or just your finger. You can also sand the parts as well now if you like.

Once all the main layers are built up, make sure to glue on the little bits that were cut off (You did save them right?) for the extra detail.

Once that's all glued up, congrats! You are about half way done!

Step 5: Glue the Lid Side

Like the body side of the rubber band gun, glue up the layers of the lid side. This is called the Lid Side because this part doesn't house the body internal structure. Screws will be put into this part to secure it onto the body, hence LID SIDE.

Don't forget the little bit details!

Step 6: Glue the Inside Mechanism

After the body and lid parts are done gluing, now it's time for the inside mechanism. Make sure when gluing up the inside mechanism parts to have them properly glued in the right order. More than likely, when you test fit them, it may be very snug. You can sand down the parts as needed.

(I have since uploading these photos changed the design of the internal parts, but only aesthetically so it will fire better and looks better as well. It is still functionally the same.)

Step 7: Cut Dowel to Length

The dowels are used to position and allow the inside mechanism to swing to allow it to fire rubber bands. You will need 1/8th dowels. You will have to cut them to the appropriate lengths.

Dowel length for pivot points: 11/16 (0.687 decimal, 17.46 mm)

Dowel length for connecting points: 7/16 (0.4375 decimal, 11.11 mm)

Keep in mind: The measurements for the dowel parts are approximate to the plywood you use. I know some 1/8th inch plywood (0.125) sold may actually be 3mm (0.118) and vice versa. Also, for the connecting points, the amount of sanding you do on the surface of those parts may also change the length of the dowel needed.

You will need two cut dowels for the connecting points, and three cut dowels for the pivot points.

Step 8: Sand Everything!

At this point, if you haven't been sanding, do it now!

I usually don't sand the inside surfaces of the gun except for where the moving parts are going to be. I also sand the inside mechanism to make sure things are relatively smooth with just enough friction for the trigger pull.

Step 9: Determine Where to Add the Screws

In order to keep the lid side secured onto the body, screws will be needed to ensure it doesn't all fall apart. When considering where to add screws, think about where the main bulk of the material may be so it can house the screws. Also consider where the screws add pressure downward to ensure the lid is sealed on top of the body so less gaps are visible along the edge.

You are going to want to drill a pilot of that is slightly smaller than the screw you plan to use, and also consider counter sinking them so they are flush with the gun (if your screws are flat heads.)

Step 10: Test Fit/Install Mechanism

At this point, your internal mechanism should be glued up and ready for assembly. Position the parts as shown on the images with the dowels.

The rubber bands that drive the mechanism needs to hook onto the internal mechanism's hook and the hook from the body side's top surface. Hook the rubber bands and test it by pulling the trigger. It should arc over enough to allow the wheel to spin over the front of the stopper and catch on the back back stopper.

(I have since uploading these photos changed the design of the internal parts, but only aesthetically so it will fire better and looks better as well. It is still functionally the same.)

Step 11: Glue Gun Muzzle

If you haven't done so yet, glue together the gun's muzzle. To make sure the muzzle are placed as accurate as possible, I generally put the gun together (have the lid attached to the body,) then glue on the muzzle and let it dry. Try not to put glue where the lid would be.

Step 12: (Optional) Stain and Seal

If you want to, you can add a stain and seal the rubber band gun so it can be protected from the elements and also allow for different variations in color for the surface of the gun. Since you are using plywood, any wood working stain and sealer would do.

Step 13: How to Load and Shoot

To load your rubber band gun, hook the rubber band onto the sights in the front of the gun, and bring it back until it goes behind the star wheel. If you want to load more, just pull the wheel back until the next arm of the wheel comes up. Then just keep loading until your hearts content, or until you run out of room.

When the rubber bands are loaded, just pull on the trigger! The mechanism fires at a semi-auto rate, so it can shoot one at a time, and it fires as fast as you pull the trigger.

Be safe, and have fun!