WLToys 12428 Crawler Conversion Chassis Parts

Last crawled date: 4 years, 2 months ago

Hi guys,
As we used to say in the software world, this is version one point uh oh. I've got the truck all put together (several times) and everything works fine but I don't expect that it's bullet proof yet. The gearbox dust cover is coming soon so hold off printing if that freaks you out.
Check out the project on YouTube: https://www.youtube.com/watch?v=pi2Jhd1oP-0
Like and subscribe if you dig it. This stuff takes a lot of work and some feedback is greatly appreciated (positive or negative). I'm thinking about doing an actual build tutorial video but part of me thinks that's a waste of time because anybody printing this thing probably knows enough to build a crawler. Crawler are easy, right? Let me know if you think I'm being too optimistic.
I was pretty down on the durability of 3D printed RC car parts but I recently discovered that good PLA printed good and hot actually makes pretty strong parts. Sadly, it's hard to tell if you've got good PLA and good settings without major testing. Seriously, I've had parts break stupidly easy that work great printed from a different spool of plastic, same brand, with the same print settings. It's annoying. Feel free to share you experiences on the YouTube videos so that maybe other people can benefit from it because building your own RC cars is super fun if they perform even close to well.
This is the set of chassis parts that goes with the solid front axle I made to convert the WLToys 12428 into a rock crawler. I modeled this stuff to work with cheap Chinese frame rails that are based on the Axial SCX10 II, so a lot of SCX10 parts will likely be useful in some way but I don't have an SCX10 so you're on your own as far as that goes. I also bought some cheap suspension links because I got tired of screwing around with DIY ones, so you can decide what you want to do on your own.
Notes:
The WLToys doesn't have servo reversing so you'll need to go with similar placement to what I ended up doing even if you want to try something different (I tried a few different positions).
The front body mount is set up for the holes that were ALREADY in the body that I used for this project, so you may want to adjust that before you put holes in a new body shell.
I believe the spacing of the holes in the bumper mounts (43mm) is standard but I'm not 100% sure, so drop me a line if you know better.
I made a front bumper mount that doubles as a mount point for one side of the servo which only applies if you are using the smaller standard 12428 servo not a proper standard sized heavy duty crawler servo. I'll be doing a mod at some point to convert to standard electronics so a servo mount will come along at that time.
The battery tray, ESC tray and mount are just some quick and dirty parts to get up and running. They seem to work fine for using the WLToys parts but there's a reason axial crammed the servo between the shock mounts so the electronics layout will also change some when I mod this for standard electronics (or you mod yours).
The rear body mount is just a kludge to get everything sitting the way I want it. I drilled holes in the floorboards to mount it and added foam to get the body up a bit higher. You'll need to adjust it to suit what you're doing or come up with something on your own.
The back half that I modeled is mounted to the frame, not the body shell.
The rear shock mounts clamp around that back axle and are far from bullet proof at this point. That's because I haven't decided how I want that to work yet. You may want to adjust them as you see fit. They do work, but you'll need to add something sticky or gritty to keep them from turning on the axle.
The shock spacer and chassis nut are just handy parts to adjust the way things get mounted. The "nut" just slides into the slot in the rail behind whatever hole you're using to mount something. The hole is M2.5.
The holes in the skid plate/gearbox are M3 except the bearing caps which I believe are M2.5. If you buy suspension links, the rod ends have M3 holes. The bumper mounts and cross brace type parts are also M3 holes. Most everything that mounts to something else is M2.5 holes. I'll be doing a BOM at some point, but I haven't gotten to it yet so for now you're on your own.
Driveshaft_Front.stl is for use extending the stock 12428 driveshaft for use on the front of the crawler. Just unscrew the plastic piece from stock and replace with this.
Driveshaft_Rear.stl is for use with a metal driveshaft with a ball and pin slider (it's like a dog bone end and goes into the drive shaft with slots cut for travel forward and back) and is the proper length to use on the rear (rear is longer). It needs needs a couple of M2 x 6mm screws to hold it onto the driveshaft (you'll need to drill holes).
Banggood screws that I used: https://www.banggood.com/300pcs-M2-M2_5-M3-Stainless-Steel-Socket-Cap-Screws-Assortment-Kit-p-1062556.html?rmmds=myorder&cur_warehouse=CN
I printed most of this stuff at 0.15mm with 1.2mm walls and heavy infill but the roll of plastic I was using was really, really crappy so I don't want to give to much advice other than to say pay attention to orientation for ease of printing and to use settings that give you nice strong parts. Nothing gave me any trouble despite using crappy plastic, so if you're struggling with a part, have a look and see if some other orientation would work better.
The dust cover for the gearbox isn't quite done yet but I don't expect it to need any additional holes. If that freaks you out, maybe hold off printing until I upload it. The truck is 100% runable with the parts as they sit.
As always, use at your own risk.
Drive to wrench or wrench to drive?