Have 3D printer...will create.

Photo of Chopper from Rebels shown for reference.

The History...

The C-series droid was introduced in Star Wars Rebels as "C1-10P - Chopper." I will build a Canon version someday, but for now, I prefer customs and I show my work below. The above left picture is what we got in the REBELS TV show, and the above right is the original concept, according to the Star Wars website, shich showed Chopper originally having a domed head and an eye similar to R2. As you can see from this picture, a lot of items were kept while others were changed. One thing that was shown in the episode "Forgotten Droid" was that Chopper "originally" had symmetrical legs similar to his right leg - the straight one.

In the 7th season of Clone Wars, we were introduced to another C-series droid - CH-33P (Cheep) which showed it having two of choppers left legs as its primary legs, but also a dome head like the original concept art and a "normal" center foot that is about 75% scale to the outer feet.

This page from here on is chronicling the build of my own C1 droid...C1-13L - Chelsea! Since this will be for my little girl, you will notice she has pink and silver parts. Also my plan is to have her be a "Factory Fresh" C1 astromech, since Chopper is a mashup of spare parts.

I originally started this using my DaVinci XYZ, but it needed replacing, so I upgraded to a Creality CR-10 with a bigger print area. Because of the issues I had with the XYZ, I didn't take pictures of the parts before assembly, but they are pretty straight forward. The files for the build can be found on the R2 Builders Club forums forums and on thingiverse.com here and here. I can't remember wher I found the rest of the files, but a Google search should turn up most of them.


I was planning on 3D printing the majority, but I was having issues with the printer at the time, so I decided to build the head out of styrene. You can click the link below for a free copy of the styrene plans.

Chopper Head Styrene Drawings

I don't remember who came up with these originally, but I used them for my build, with a few slight modifications.

Side arm boxes:

Base ring and top ring.

All ribs.

Bones of the head done.

Top outer ring and top plate done.

The original prints called for one .080 skin with the details milled into it at .040. But based on my experience with my ArJay Astromech, I decided to make 2 layers of .060 (1mm) with the inner skin flat and the details on the outer skin.

I didn't take pics, but I used my HIPs slurry to fill holes and sanded it down smooth. I also added hand-crafted doors made from 6mm Sintra (PVC board) to the head.


Click on each pic for higher resolution.

Most of these pics came from when I was originally building Chopper, but some parts have been/will be modified for Chelsea.

I printed the "bones" of the body from files I got from ProtoPROPS on Thingiverse.com out of leftover filament I had lying around...which is why some parts are black, some "clear," and some yellow, as well as white. I love this design, but I'm gradually going through each piece cleaning them up and modifying them slightly to add some minor details.

About halfway through printing the top ring, my DaVinci XYZ printer died and I switched over to a Creality CR-10 with a much bigger build platform. Some of these parts are trial and error, so if you print your own, you may have better luck.

This "Front Scanner Dish" didn't come out like I wanted, so rather than reprint, I just used a little Bondo to smooth it out. Also, the "Body Chest Plate 1-1" (the one that is slightly askew) broke as I was putting it on, so I just hot glued it together in this pic, but removed it later for the final build. I also modified the main panel file to not have the screw holes for that small plate. Sorry, no picture yet.

Power coupling (Chopper) covered by a door (Chelsea)

Auxillary Arm - The original plans call for a partial door that leaves the arm exposed. Since I'm making a "factory Fresh" version, I reworked the .stl file and created a door. For this print, it is solid, but in the future, someone can take it and make it 2 separate pieces with a hinge if they so desire.

Auxillary Arm Door Panel - Printed on CR-10 using Cura with "Trees" support

Right Leg Mount - The back panel next to this mount, as well as the one from the other side and the back panel, I made out of 6mm Sintra. (pictures below)

Hex Adaptor

Left Leg mount - SPECIAL NOTE: This part was printed incorrectly and has been fixed. The channels for the bolts that allow the leg to move should be going counter-clockwise from the center. The corrected part is shown in other pictures.

I primed the whole body, then hit it with the first coat of white. You can also see the full arm installed and the correct lef leg hubb in place.

PAINTED!!! Yes, there are some slight booboos in some places, but this is for my daughter and she's happy with the way it looks for now...so much so that when she saw it painted like this for the first time, she actually squeed...This is also a steep learning curve for me in dialing in 3D print settings, and I may replace some parts in the future when I have the extra time and cash.

I got the arm files from Thingaverse as well, and the maker did warn that the 3/4" pipe file may be too short. And it was for the frame I'm building, so as you can see above, I used 3/4" PVC instead.


In my search to find legs for Chopper, I found several people with them, from 3D printed, to wood, to even someone who made them out of Styrene like what is available for a standard R2 unit. But in all of that, I didn't find anyone with stl files (3D print) or plans called a "Flat-pack" available, like the head. So I started working on my own. They are still a work in progress but you can get them below. And yes, I used the R2 leg patterns for reference.

Click on the pics for a higher resolution for download, or get the full flat pack - all parts or 3mm and 1mm separate - below.

If you would like to download and use my plans, please feel free. But keep in mind, as I said, they are still in a testing phase and subject to change. If you notice anything in error, please feel free to contact me to let me know! As you can see, I have the files for the Chopper right and left legs, but for my final build, I'm only using the files for the right leg (with a modified foot for the left) for the "factory fresh" look.

Chopper Legs - Full Set Updated 4/25/2019
Chopper Legs - 3mm Parts Updated 4/25/2019
Chopper Legs - 1mm Parts (Skins) Updated 4/25/2019

  • Right Leg
  • Left Leg
  • Ankles
  • Feet
  • Battery Boxes


    PLEASE NOTE: I decided to go with 3D printed legs and I'm in the process of printing all those pieces. Once completed, I'll post an update.

    This is the right leg mocked up with cardboard. Some extra parts were made after construction because, in an Alpha-test, you find things that you don't think of during the design phase on the computer.

    Right upper leg done. During the Beta test phase, the skins on the upper curve will be added.

    And checking the placement on the 3D printed body.

    And checking the sweep for 3-leg mode.

    So after lots of swearing, going back to the drawing board, and a couple of sheets of plastic, I finally have the first beta version of the right leg:

    The is the first build of the right leg made from Styrene. After I built this, I noticed that the top and bottom halves of the leg need to be separate, so the plans were adjusted accordingly.

    This pic is using a piece of 1" PVC tubing for the ankle tube. This was changed to a 3D print tube and ankle for my build.
    And the battery boxes will be more complete.

    I installed a temoporary motor for the wheel, and the wires run up the chase pipe just like I planned.

    And the battery box needs a little work, mainly to ensure the skin stays on better.

    I completely redesigned the ankle to be all one piece so that a threaded rod can be used to go through it, the piston, and then connect in the upper part of the leg.
    You can also see in this pic that this is the second right leg I constructed from the updated plans to make the bottom part of the leg separate so it can be placed in the right spot.

    I originally designed the bottom of the piston to have an inset to hide a nut, but redesigned it to be a "tab" that...

    ...would fit into the inset of the ankle tube for proper placement.

    And seated together, it is in the proper position for the leg.

    First off in this pic, you'll notice that I cut off the major portion of the face of the upper leg. (The flat pack will be upgraded to show this cut line soon) This was to get access inside to do this: These are piston caps I designed that will have the threaded rod running through it to hold everything together.

    These were originally designed to be a part of the full 3D printed leg I'm designing, but I wanted to have them as an option for the Styrene build, too.

    Marked to make sure the cap would sit in the right spot.

    Glued the cap in with Weld-On3 and then used Styrene slurry to permanently fix it in place.

    I used a locking nut on the bottom of a #10 threaded rod for the ankle (This will be redesigned a bit to allow the nut to seat inside better).

    For the top, I used a flat washer, locking washer, and a wingnut to put everything together.

    And then a dab of hot glue on the extra bits just to get a look at the whole thing together... These pics show a bottom cap I designed and 3D printed instead of using styrene so the ankle tube would set properly.

    3D files will be released here soon!

    Now on to the feet!

    More pics coming soon!

    Left Leg (for a Chopper build)

    This is the very first Beta Test of the TMA-produced Styrene Leg Flatpack. It is an ongoing project and this tutorial will be added to the full build files to be release for free to the Chopper Builders Facebook page as well as Astromech.net. This is my testing of the Left Leg for Chopper, but I will not be using this for my build.

    All parts (except Top Inside Supports [TIS] shown.

    Drill a pilot hole in the chase marker to line up the Base Mid Plates (BMP).

    Clamp them together and drill out whatever size chase you prefer. It's marked for a 1/2" hole, but you can make it larger or smaller as you like.

    Drill the same hole for the Base End Plate (BEP). Glue that to the Base along with one Base Side Plate (BSP)

    Glue in the BMP parts. One does get attached securely to the BEP.

    Glue on the other BSP.

    And the top 3mm skin now is glued on.. IF YOU PREFER, similar to the R2 leg construction, you can put on the top plate before the BSP to add more glue for security if you like.

    Now starting ont he top.

    Drill pilot holes in the center hub and for the leg bolts.

    Top Base Plate Outer (TBPO) is glued onto Top Base Plate Inner (TBPI) at champher line. Line up with a pilot hole in the chase marker.

    Champher the ed=nds and drill the 1/2" hole

    Secure the end plates to the top base, and glue in the Top Inner Supports (TIS)

    Attach the Side Arch Supports (SAS)

    and the Angled Arch SUpports (AAS) Pay attention to the champher ends.

    Start with the Upper Arch Supports (UAS)

    And finished.

    Now add the top 3mm Skin. I'm leaving the center hub uncut for now until I get the arched skins attached. Also, you will notice with the top and bottom being built separatel, they are offset just a bit. This is in line with the Canon sources.

    More pics coming soon!


    The ankles were part of the Styrene Flat Pack, but have been removed in favor of the 3D print file now available. I still have those plans if you would prefer to make them out of styrene.


    As with the legs, I started with cardboard mock ups just to check for measurements, placement, and such.

    As I said above, I'm using the R2 leg patterns for reference. As such, there is only one spot for a wheel per foot. Based on what I've seen from others, I may include an option for 2 wheels per foot in the future.

    And just for fun, here's a 3D foot I worked up. The advantage of this is I can design the interior to accept 1 or 2 wheels with a drive motor. The ankle wedge is a separate part that will be available for free download soon.

    3D DESIGN - See below

    Center Foot Styrene Flat Pack V2 Uploaded 5/16/2020

    I worked up a flat pack for a styrene center foot build and you can get the files for free by clicking the link above. They are still very much a work in progress, so be prepared for some parts not to work out until I can update with the final plans. The following pics were taken of the build of the 2.0 plans, which which was a Beta build to show areas of improvement for the 2.1 plans. Again, these were based off the R2 plans, and some liberties were taken, but the build method is similar.

    UPDATE 5/17/2020 - After the final season of Clone Wars was released, I found great reference images of the center foot thanks to the new (albeit temporary) character of CH-33P (Cheep). In those pics, it shows the center foot as being roughly 75% of the side feet, so the flat pack above has all parts reduced by that much.

    To start, here's all the parts cut out but not trimmed.

    After trimming and drilling pilot holes in the crosshairs, leave the plans glued to two of the CFMB1 pieces, remove them from the other CFMB1s, and glue them together using the drill bit as a guide.

    Clamp the two sets together so the necessary holes can be drilled. Trim out the section of the CFMB that will be access for the wheel mount nut.

    Using the drill bit as a guide again, glue on one CFMB2 piece to each side. Clamp together to set.

    I clamped my setup to the drill press base and drilled all inline holes at one time. The R2 plans call for a larger hole on the outer CFMB1, and that can be done if desired prior to glueing together.

    Glue in the valley base.

    Use the drill bit to line up the ankle holes and glue on the other side.

    Wheel mounts.

    Line up with the drill bit and clue together.

    Once the glue is set, drill out a 10mm hole for the caster and glue to the other parts. After this is set, use a sander to make the sides flush for the next step.

    Glue on the front and back.

    Glue on the base.

    Add the ribs.

    Glue on one of the sides.

    After this step, you have a choice. The V2.1 plans will have an option for a removable panel to access the bolt hinge for the ankle. If you want to install it permanently, do so now then add the last side prior to finishing. If you want to wait, those details are coming soon.

    On to the base ring. This ring is kind of tricky. The objective is to have it line up with the sides of the foot, and to do that, you need to cut out the inner section (pilot holes to start, or however you wish to do so), then glue the uprights (skirts) to the trim. Once this is done, chamfer the edge inward so the ring rests on the side of the foot. Or you could do the easy thing by trimming even with the skirt and backfilling with styrene slurry... (see below).

    Test fit of 3D printed parts. The styrene plans will be updated with the proper placement of the side pieces, and even though it's not very pretty, I cut a hole (not shown) to access where the ankle pin will be. I'm going to use a 10mmall-thread rod cut down to 2.5" long and use lock nuts on each side to hold it in place. This is simply in case I need to remove the foot from the ankle later.

    First slurry layer done. Skins will go on after this is cured and sanded.

    And here is the finished foot, complete with all filler (I didn't see some errors until late) and the ankle and foot wedges attached. I'm not installing the wheel until it's ready to go on the droid.

    Here's how I designed the foot wedges. There's room enough to make a cut out (this was rough, but I added a clean cut to the templates above) so you can put in the ankle hinge and access the bolt for the wheel.

    And just to compare, here's the regular R-series center foot.

    See below for the 3D foot, ankle, and brace upgrade I designed.

    And now to mounting the center foot!

    did a slight redesign of the ankle (and another mod after this print to make it better) so it would mount inside the adaptor.

    I love it whan a plan comes together... And interestingly enough, this is in just the right spot that it is PERFECTLY balanced on this one leg!



    More pics coming!

    Custom Designed 3D Parts

    This section is constantly being updated.

    Although there are a lot of 3D .stl files available for Chopper, there are some that I do believe others have designed, but have not made them available to the public yet. So I got tired of waiting, learned Blender, and got to work. These files are available for free download and will be upgraded from time to time. If you do download a file and discover an error, please let me know, or feel free to fix it for yourself and make it available to the public as well. Happy printing!

    Ankle Cylinder - created with a wide chase in the center for motor wires. The large inset fits a 1/2" PVC tube that serves as the spine for the leg. Holes near the ends are for the bolt up from the ankle and the small inset is for the nut to seat flat. This is hidden by the Leg Piston (below).

    I redesigned the cylinder to be a part of the ankle. In doing so, the pistons were also redesigned to have a "tab" that goes into the "slot" on the full ankle. A cap was designed to go inside the main leg body so that a threaded rod can be used to hold everything together as shown above. For this I used a #10 threaded rod, locking nuts for the bottom where it sits inside the ankle, and a flat washer, locking washer, and wingnut for the top inside the leg body.

    Other options available are the spacers for the bottom of the legs between the leg and the ankle cylinder. They are each labeled "L" or "R" for the appropriate side. The right side has a noticable offset for proper placement (long side towards the front).

    PLEASE NOTE: All 3D files are constnatly being updated, so please feel free to check back often to see if there's anythign new.

    Ankle Cylinder
    Cylinder End Puck
    Full Ankle And Cylinder

    Left Leg Spacer
    Right Leg Spacer

    Leg Piston - Designed with the angle at the top to connect with or set inside the leg angle. Also has a large inset at the bottom to hide the ankle nut on top of the cylinder and a narrow deep inset for the end of the bolt.
    Leg Piston
    Leg Piston Parts
    Leg Piston Cap

    Left Leg Parts - 2 pieces. Pretty self explanitory. Get the Shoulder Puck for the left leg below.
    Left Leg Center(Green)
    Left Leg Cylinder (Blue)
    Left Shoulder Puck

    Right Leg Parts
    Right Leg Cylinder (Yellow)
    Right Leg Upper (Green)
    Right Shoulder Puck (Blue)
    Right Leg Cap (Silver)

    Updated C1 Eye - This is not my original design. Someone else made this, I just used Blender to smooth it out.

    SKINS - Since I decided to make my C1 a "clean" droid, I upgraded a couple of the skin files oroginally made by ProtoProps that can be found on Thingiverse.com


    FIRST PIC - this is a full panel print since the bones done by ProtoProps don't have attachment points. Another option is being worked on that will allow this to be a door that can open.
    SECOND & THIRD PICS - These are two variations of the #11 panel. The firs is a full panel print and the second is just the lower half if anyone has the desire to make this a moveable door that works with Proto's original.
    FOURTH PIC - This is a modified version of the #13 panel without the screw holes for the small "patch" panel, as well as the "well" for the mount screw behind the patch raised even with the rest of the piece.


    I decided to work up a 3D design of the center foot for the fun of it and this is what I came up with:

    Center Foot ankle - V2 (as shown below)
    Center Foot wedge
    Center Foot Shell As shown in 3rd pic above
    Center Foot Wheel Base as shown in the 3rd pic above
    Center Foot main access door

    As mentioned at the top of this page, ProtoProps on Thingiverse has a great set of files for the body. One of the parts that fits his design (I can't remember if he designed it) is a center caster wood brace. It comes in 3 parts - front, back, and wheel mount. These parts are for using a piece of 2x4 wood to mount the center caster wheel. What I did for my C-series is design a brace adapter that spans those parts and allows the ankle piece to slip inside and be bolted securely all together.

    The dark blue and green pieces are from the wood mount files. The pink is the ankle I designed for the center foot. The light blue is an adapter that attaches to the wood mounts and allows the ankle to slip in and be bolted to it. As you can see on the ankle, I redesigned a little so a nut can slip in the side and be covered up by the adapter.

    Center Foot Brace Adapter