THUMPER 1:8 scale RC Car CJ7 Rock Crawler by BlackCrow (No supports!)

***Assembly Videos At bottom of this page*** Are you new to Black Crow Prints? All the STL files are here free on Printables.com. A non printed parts list is below along with easy step by step assembly videos. Help is available, usually within 24hrs. You can contact me thru private message or comments on the makes and comments tab. File updates are always listed at the bottom of each description page. Ways you can help: Let me know when I make a mistake. Share your builds with friends on social media and subscribe to my YouTube channel. If you would like to help me provide these models free to others you can become a “My Club” member. No obligation implied and you will get no special treatment from me other than my appreciation. .. Now go build an adventure. ________________________________________________________________________________________________________________ Now, I am proud to introduce Thumper. Thumper is a scaled CJ7 rock crawler. These crawlers are common in the western and south eastern USA. This model is very close in build to the real thing. Scale puts the 120mm tires at the standard 37" tall. The front axle has been moved forward about 10 inches and the back axle moved back about 9 inches. The seats have been moved back and mounted to the roll bars for safety. A race fuel cell has been added and raised above the frame for clearance. Without a trailer hitch the approach and departure angles are 90 degrees. The ramp over angle could be better. You can't have everything. Update: New clearance mod improves ramp over angle. (belly clearance) See High Clearance Mod below in link to build options. When building a real rock crawler you want the tires to be as big as you can swing while keeping the body and center of gravity as low as possible. You want lots of power while staying light and nimble. Cooling the engine is usually an issue and it has to practically run upside down without leaking fluids. To be honest the CJ7 is not the best choice for this and they are becoming too valuable to destroy. You could technically buy every part of a CJ7 without buying any actual AMC or Jeep parts using 100% catalog aftermarket parts. This model is a fully home built custom crawler.

This 3D printed build was designed to be strong and easy to work on. I appreciate the “fully 3D printed” models put out by others however I tend to be a bit more utilitarian. This model uses RC hobby standard metal axle gears and drive shafts. The transmissions use an amazingly strong belt system that is very quit. The motor/transmission sets are easily removed and swapped without removing axle links or suspension. The battery module slides out the back for easy charging or swapping. This model has room for one or two 2S 7.4 volt shorty Lipo batteries. Before building please read carefully. This model has options. In an attempt to keep things simple the motor/transmission build options and other options are in separate listings. Build this Jeep chassis, pick your motor/transmission setup. Then combined or swap out Motor/transmissions. You also have door and top options along with custom options in the Thumper aftermarket store. The half top option requires a different rear tub found in the Door and Top Shop. The Four Wheel Steer option also has a separate listing for it's custom parts. All the STL files you need are listed with links below. Parts are numbered in order of use. Parts files are in proper orientation to print. Assembly videos at the very bottom of this page. _________________________________________________________________________________________________________________ Videos: Introduction here. !!!! Assembly videos at bottom of this page !!!!!

Introduction to Four Wheel Steer version. **Assembly videos at bottom of this page!!**

________________________________________________________________________________________________________________ ***Builds By Others*** Action Video below by independent Builder Lasz YouTube channel here Top and doors in this video by MaSt52 here

_______________________________________________________________________________________________ Links to build options: (You need to pick a transmission, The rest are optional) Metal Gear Motor/Transmissions https://www.printables.com/model/769045-thumper-and-morrigan-cheater-metal-gear-transmissi Printed Gear Motor/Transmissions https://www.printables.com/model/356820-thumpers-transmission-shop-for-18-scale-rock-crawl Four Wheel Steer Option https://www.printables.com/model/394110-thumper-4ws-rear-steer-mod-18-scale-rock-crawler-b High Clearance Mod https://www.printables.com/model/1217597-high-clearance-mod-for-thumper-rc-4x4-crawler Optional doors and tops https://www.printables.com/model/629922-thumper-door-and-top-shop Aftermarket Parts Shop https://www.printables.com/model/356827-thumpers-after-market-shop Requested and Retired parts https://www.printables.com/model/396992-requested-and-retired-parts Top Shop https://www.printables.com/model/629922-thumper-door-and-top-shop GoPro Mount https://www.printables.com/model/372044-thumper-gopro-mount-by-black-crow Trailer Hitch Options https://www.printables.com/model/279936-18-scale-110-scale-pintle-and-pintle-ball-combo-tr ________________________________________________________________________________________________________________ Motor Transmission Options You have a wide verity of options when it comes to motor transmission setups. First choose from printed gears or metal gears. Then see more options on Transmission pages. 3D printed gear transmissions here: https://www.printables.com/model/356820-thumpers-and-morrigans-transmission-shop-for-18-sc The 3D printed gears work very well unless you stay in the throttle for an extended period of time or use high rpm motors. Metal gear transmissions here: https://www.printables.com/model/769045-thumper-and-morrigan-cheater-metal-gear-transmissi The metal gears are better for people that push the limits. This is the better choice for 540 motors. The Fusion SE 1,200kv is awesome! This is also better if experimenting with 3S batteries. Next you have the option of Four Wheel Steer Parts marked Not 4WS will not be used on 4WS. Additional parts needed found in 4WS post https://www.printables.com/model/394110-thumper-4ws-rear-steer-mod-18-scale-rock-crawler-b This option is intended for the Crawlers. Keep in mind this option works best on rocks, dirt and slippery surfaces. If reduces the turning radius by about 70%. With locked axles it is not practical on carpet and other sticky surfaces. The good news is that you can turn it off. With just a flip of a switch you are back to front steering only. See more info on the 4WS Page listed above. __________________________________________________________________________________________________________________ Wheel base 12 ¾" (325mm) Wide (Narrow tires) 10" (255mm) (Wide tires) 10 ¾" 274mm Long 17 ½" (445mm) without trailer hitch. Tall 9" ( 229mm) 90mm shocks stiff for basher or 100mm sagging for crawling. __________________________________________________________________________________________________________________ Supports: No supports needed EVER! Supports are built into the Model. (Because of the built in supports and fine detailed areas a 0.4 nozzle or Adaptive slicer must be used) ________________________________________________________________________________________________________________ Printer Settings: 0.4 nozzle (no bigger because of built in supports) .2 layer Hight (no bigger) Wall Thickness: 0.8mm, 2 layers at 0.4mm Infill: Normal parts - 15% Roll bars - 25% Axles, links, hubs and wheels -80% (100% can exaggerate over extrusion problems) ************************************************************************************************** Special settings for radiator: Infill: Rectilinear 30% Layers top 0 Layers bottom 0 ************************************************************************************************** ________________________________________________________________________________________________________________ Filament: Models are designed around the use of a strong PLA. For best results use Prusa PLA, Inland Plus, CC3D Max, ( Hatchbox PLA does not test well with my models) Warping - Prusa printers with PLA plus - adjust bed temp to 65 degrees. Creality printers with PLA plus - adjust bed to 60 - 65 degrees. ________________________________________________________________________________________________________________ Parts Needed: Links are US Amazon Affiliates Axles : - AR44 gears- “Ring and pinion” need two sets, one for the front and one for the back. ratio should be 8T-33T for all models except Basher build with parallel 2S batteries. Then go with ( 8T-24T) https://amzn.to/3JgXBx2

- Axle shafts, Front and back - Compatible with Axial SCX 10 https://amzn.to/3PXuBOA

- Drive Shafts, Front and back - 105-155mm (5mm) (Actual measurements are 110mm to 120mm) https://amzn.to/3JgYBB6

Axle Bearings: 4 bearings 7x14x3.5 ( 687) https://amzn.to/3W1t3Xs or https://amzn.to/4wdbeEp 2 bearings 10x15x4 (6700-2RS) https://amzn.to/4cPEnfx or https://amzn.to/4wK9Fxw 10 bearings 5x11x4 (MR115-2RS) https://amzn.to/3VTBK68 or https://amzn.to/4gMFrVZ Steering Servo: https://amzn.to/4cVPt2r Battery- 2S Hard Case Shorty https://amzn.to/43ZbhpT or https://amzn.to/4yv7CyR XT60 connectors - https://amzn.to/4fX27Qi 4mm Banana 90 - https://amzn.to/40Br12r Wire - 12 AWG .6M (2 feet) - https://amzn.to/3TadxGy Tires: 1.9 inch center 120mm outer diameter. Red Jeep has 43mm wide. https://amzn.to/3PVOCF2 Yellow jeep has 52mm wide. https://amzn.to/46oaVuz Note two size wheels. Narrow for 43mm and Wide for 52mm. Shocks: Important!!! 90mm - 100mm only !! Shocks more than 100mm long will over extend the stock steering. Shocks under 90mm are too short to reach the axles. Rock Crawlers- I suggest 100mm on Rock Crawlers. Just let the shocks sag and articulate. 100mm internal spring- https://amzn.to/43XIEJz 100mm Exterior spring- https://amzn.to/4aThfLs Bashers- I suggest 90mm on bashers. 90mm lets you increase the spring tension without raising the center of gravity too high. Shocks more than 100mm long will over extend the stock steering. You can Use 100mm shocks on Bashers. It just raises the center of gravity and flips over more easily. 90mm internal spring- https://amzn.to/3JdtPsW 90mm Exterior spring- https://amzn.to/49tllbW Acrylic 0.4mm thick acrylic sheet for window glass

---Transmission Bearings and more parts needed. Go to Motor/Transmission page--- https://www.printables.com/model/356820-thumpers-and-morrigans-transmission-shop-for-18-sc Screws: (screws are regular machine thread) M2 nuts 11 M2 x 4mm 48 M2 x 6mm 60 M2 x 8mm 42 M2 x 10mm 71 M2 x 12mm 5 M2 x 16mm 2 M2 x 18mm 4 M2 x 20mm 5 M2 x 25mm 4 32 M2 screws optional lengths from 8mm to 12mm for wheels. -------------------- M2.5 x4mm 3 socket head (for Flash hobby motors) or use new no screw option -------------------- M3 eye bolts (optional) 2 https://amzn.to/3TViAui M3 nuts 37 M3 Nylock nuts 8 M3 x 4mm 4 M3 x 6mm 2 M3 x 8mm 4 M3 x 10mm 35 M3 x 12mm 16 M3 x 14mm 30 M3 x 16mm 5 M3 x 20mm 10 M4 Nylock nuts 4 ( wheel axle nuts) Thread Locker (Loctite) ( Additional parts needed in transmission/Motor build.) Printed gears transmission- https://www.printables.com/model/356820-thumpers-transmission-shop-for-18-scale-rock-crawl Metal gear transmission- https://www.printables.com/model/769045-thumper-and-morrigan-cheater-metal-gear-transmissi *All parts for this model were purchased on Amazon ________________________________________________________________________________________________________________ Tools: Drill with 2.5 bit, File, Vice or clamps, plyers, utility knife, screw drivers, wiring tools, soldering tools cutting: Hack saw or Dremel ( cutting 5mm rods) ________________________________________________________________________________________________________________ More info: - Roll Bars - I know I am going to get some resistance on the roll bars… Maybe hate is a better word? When I started designing the roll bars I actually planed on breaking them up into pieces. I just didn't want printability to dictate style. Then it became a fun challenge to print as one part. Then I realized how strong and awesome they are as one part. Then I though maybe you appreciate the design too? You can lift and carry the model around by the roll bars! I have flipped and rolled the red jeep at basher speeds on grass and carpet more times than I can count - Plus four times on concrete. All before the fist pictures or videos of the RED jeep ware taken. … I know that I wasted more material in the supports than I used in the actual bars but I think it is worth it.

__________________________________________________________________________________________________________________ Assembly Video 1

Assembly Video 2

Assembly Video 3

Assembly Video 4

Assembly Video 5

Rear Axle Assembly Video 6-A

Front Axle Assembly Video 6-B

4WS Axle Assembly Video 6-C

Assembly Video 7

Assembly Video 8

--------------------------------------------------------------------------------------------------------- Optional Four Wheel Steer Assembly Video

__________________________________________________________________________________________________________________ Disclaimer - Lipo Batteries can be dangerous. Build at your own risk. ______________________________________________________________________________________________________________ Before you build: - ) 5mm rod. The videos show stainless steel rods. 5mm Brass rods are easier to work with and is still plenty strong. If the rod does not fit in the bearings first make sure that the ends of the rod are not damaged. Second if needed reducing the diameter of the rod is actually very easy. Place the rod in a SMALL drill and spin the rod in a fold of 100 grit sand paper. Be very carful with powerful drills as they can catch your fingers in the sand paper and possibly injure you. Never do this with a lathe. Lathes can kill you!

- Fender Print Direction The tops of the fenders push the angle limits of what most printers can do. Make sure the tops of the fenders are rotated to face the cooling fans.

Update: Jan-25-2023 adjusted 30-60Amp ESC mount. 60amp ESC sits on it's side with fan facing perforated radiator, ( see special radiator printer settings above) On Off switch goes to either side. Receiver mounts on top of steering servo with double sided tape. Update: Jan-31-2023 Added 3 part roll bar for Ender3. Update: Feb-10-2023 Improved rear frame- (048FrameRearLeft 049FrameRearRight) Update: Feb-14-2023 Improved roll bar supports Update: Feb-17-2023 007Cowl fixed hole alignment issue Special thanks to Brace91 for catching many mistakes and beta testing the 4WS option. Update: Mar-23-2023 updated axles for tighter fit with axle nuts Update: Mar-23-2023 Added 4WS option Update: May- 29-2023 Much needed update to seat. Old seat mover to retired parts post Update Oct- 24 2023 045FrameFrontLeft - Added option for servo reinforcement screws. (1x- M2 x 25mm, 1x- M2 x 15mm) These screws reinforce layer line weakness at servo mount. Update Nov-12 2023 Front Fenders -Added layer adhesion screw above shock mounts for greater strength. Update Dec-10-2023 Axles and axle videos have been updated to the heavy duty Morrigan style axles. ( I had to move a lot of things and update links. If I missed something tell me please.) Update Jan-12-2024 Added Top Shop here Update March-17-2024 Added Metal Gear Transmissions here Update Aug-9-2024 (rear non steer axle) 201AxleHousingRearRight, 203AxleHousingRearLeft- added option to reinforce with 5mm x 63mm rod for extra strength Update Feb-22-2025 064LinkUpperFront - Adjusted for better steering clearance and reinforced (Thanks to help from RN's RC) Update Feb-23-2025 201 and 203 Axle Housings- Better Shock clearance. (Thanks to help from RN's RC) Update April -6- 2025 Added high clearance Mod to main options above Update April -14 2025 022FakeFloor fixed unsupported area. Update Oct-11-2025 Updated rock sider 013 and 014 for easier printing _________________________________________________________________________________________________________________ Builder Videos: LegoManiacman Video 1 RN's RC Inaugural, Hill Climb MAX3DRC- Video1 ,Fusion SE Video2, cruise control Radiomaster Video3 Stuck in the mud Video4 FPV Parts 1, 2 Steve Eckerlien Video1, Video2

__________________________________________________________________________________________________________________ Parts designed by others: Half Door that work with original roll bars by MaSt52 here Top That works with original roll bars by MaSt52 here Extended battery compartment by Steve Eckerlein here 1.9 to 2.2 Wheel adapters by Steve Eckerlein here FPV camera mount by Steve Eckerlein here Bumper with light mount by Steve Eckerlein here __________________________________________________________________________________________________________________ Prusa and Bambu printers usually print this model without any problems. Other printers might need to be dialed in. I picked this video because it explains all of the horizontal expansion settings. In most cases you will need to set to -0.1 to -0.3.

__________________________________________________________________________________________________________________ License- Some file sharing platforms are taking files off sites and placing them on their sites without the knowledge of the designer. I am not OK with that. These models are updated here with the feedback given here. I intend to keep the home of this model here. This is the reason for the strict license of this model. I am not concerned with hobbyists sharing and remixing parts of this model, Enjoy