Building a small scale crawler hauler

[Haastnooit]

First I was planning on posting the progress of this new project in my power wagon thread but today I decided to make a new dedicated thread for the project.

Anyhow ... I have not been playing around much with the small scale crawlers past months. From the start of getting in to the small scale crawling scene , I went in no time from none to four 1/24 scale rigs, first I got two FCX24 power wagons and added two used SCX24’s (JLU and C10) later on.

When wrenching on them I found out I actually don’t really like the fiddly small hardware on these kind of rigs. The M2 hardware on the FMS is small but still somewhat do-able, and thus acceptable when working on them for short periods of time. When I got the SCX24’s and was confronted with the M1.4 hardware for the first time, I experienced it could be way worse. I really dislike the ultra-tiny M1.4 hardware so much that I decided to sell the SCX24’s.

Now I am re-entering the small scale world with a new project. I will combine various skills (some old and some new to be learned), such as designing, 3D-modelling, 3D-printing, building and painting to hopefully produce a satisfying result. I know I will enjoy the entire process from start to finish, so I feel the result is of less importance.

I am going to make a crawler-hauler for my FCX24 power wagon. I ordered two 1/18 scale Eazy RC towing vehicles, the Patriot and Glacier.




Eazy RC Glacier

Eazy RC Patriot

First part of the plan is to design, 3D-print and build a modular flatbed trailer to be towed around by the Patriot. The towing vehicle itself I hope to dress-up with some scale accessories, paint it and learn to do some weathering.

Secondary plan is to add a goose-neck to the modular design of the trailer and add a living space like the longer crawler-haulers. Off course the towing vehicle for the goose-neck trailer will be the Glacier.

Upcoming weekend I will start with the basic design of the modular flatbed trailer … to be continued !

 

[Tex Koder]

Sub'd for more.

 

[Ron Burgandy]

The ol square body Chevy looks cool !!!

 

[Haastnooit]

Today I started work on designing the flatbed trailer. With a ruler in one hand and the FCX24 in the other I defined the needed flatbed area to place the truck on to be 140mm wide and 250mm in length.

In order to be able to modify or expand the trailer in the future I wanted the design to be modular, also the size of my print bed has to be taken in perspective when determining the dimensions to use. I chose to make the flatbed area out of three modules and added the triangle as the fourth one. Below a picture of the 2D concept design with some dimensions. From left to right I call them frame A, B, C or D-part.

I do not want to make a fully floored flat trailer as I think this is too simple looking and I want to add some more detail to it. I also need a location to store the ramps, I want them to be stored between the wheels of the loaded crawler. How this needs to look I will decide later in the build.

So for the crawler to stand on I am going to add “treadway” sections (?) for the wheels to ride on. I do not know how you would call these parts as English is not my native language. I think you will get what I mean by looking at the picture or you will find out in the future if you follow this build.

Now that dimensions are determined I will focus on how I want all modules to be connected and also look in to wheel options for the trailer.

See you later …

 

[Haastnooit]

After looking for wheels on the internet this afternoon and not being able to find some cheap 1/18 scale wheels that would look acceptable on the trailer I have decided I will use the stock power wagon wheels. I have 10 of those laying around. The trailer is going to have dual axles and when using the old power wagon wheels I can add a spare tire to the trailer later if I want to. Added bonus for re-using what I have !

Based on the dimensions of the stock power wagon wheels I made a 2D design for a bracket to attach the dual axles to the frame of the trailer. Also made a design for the fenders.

I have been thinking about glueing everything together, just for the ease of it. Also I do want to minimize non scale hardware being visible as much as possible. A goal which is easily achievable with glue … but that would mean losing the whole modular concept. So tonight I sat down for the challenge on using hardware in invisible places. I just finished finalizing the plan, it took some effort but I think I succeeded and worked out the needed thickness of all the frame parts, and determined all screw positions. I managed to achieve my goal in such a way I will be able to use M3 buttonhead screws for compete assembly and hide "all of them" from sight.

In the pictures below all screw positions are added in red.

The screws for the treadways cannot be hidden and are visible so I plan on using the small (but hated) M1.4 screws, I had purchased for the SCX24 platform, to secure them to the frame. Guess I am ready for producing some 3D models based on these 2D plans. Then export the STL files, a quick slice and on to printing the parts …. Yesssss !

 

[Ron Burgandy]

This looks cool man !!!!

 

[Haastnooit]

This week hobby time will be limited due to lots of birthdays of family and friends, I don’t expect to make any real progress on the design. Still need to work out the spare tire position, design the ramps (and ramp storage on the trailer) and make a hitch to fit the Patriot. I will focus on the hitch first …

I did convert all the 2D designs to 3D models and export the STL files.

I work at home so I have been running the printer during office hours yesterday and today, also made some prints during the night. Last print just finished a few moments ago. When printing was ready I noticed I forgot to subtract two M1.4 screw holes from the frame C-part when creating the 3D model. I guess that is what you get when working on stuff until the late hours. I will need to drill holes to address this, luckily I can use the treadway itself as a drill-guide.

Below some pics of the printed parts. I used Polymaker PLA Steelgrey for the frame parts and black for the treadways and fenders.

Next task: assembly and test fitting the power wagon.

 

[Haastnooit]

Tonight I assembled the trailer. I planned on using nuts and bolts but when putting all parts together I noticed using the nuts is unnecessary, so I skipped them.

Connected frame A to D-parts with six M3x16mm screws, the end of the screws sits flush with the frame.

The heads of the M3x12mm screws that attach the axle brackets are sunken in to the frame, again no bolts and the end of the screw is flush with the bottomside of the axlebracket.

The treadways are secured with eight M1.4x10mm screws, they make the whole structure very rigid as they are screwed in, in three of the frame parts.

The fenders are connected to the frame with two M3x12mm screws, no bolts and flush with the backside of the frame. The buttonheads will be hidden from view by the wheels.

Unfortunately I ran out of time and could not get the wheels installed. I want to use some all-thread M3 rod for the axle’s, but I will have to search my shop for it. I know I still have some …. But where ?

Catch you on the next update …

 

[Ron Burgandy]

That is sick !

Has to be the nicest 3D printing I’ve seen !
Technically I havnt seen much 3D printed stuff but that looks really good !

 

[Doom!]

Coming along nicely. Very cool. Did you decide on which wheels you are going to use on the trailer?

 

[Haastnooit]

Coming along nicely. Very cool. Did you decide on which wheels you are going to use on the trailer?

For now I am going to use the stock power wagon wheels, I have 10 of them in the spare parts bin.
Most cost effective choice …

 

[Haastnooit]

So no M3 all-thread to be found anywhere … I wanted to fit the wheels ASAP to get a better look and feel about the trailer. Therefore I decided to go another route and use some longer M3x30mm bolts and nuts to make a single “stub axle” for each wheel. I printed some wheel spacers to get the right off-set for the wheels, on installation I added two steel washers to fine-tune the offset, guess my measurement was off.

More detail pic of the “stub axle” …

With the wheels installed it was clear that I made the fenders way to wide.

I shaved of 5mm on the width of the fender and made a V2 version. This looks better …

The overall width of the trailer is bigger then I anticipated, the V2 fenders take 10mm off. But it is still relatively wide compared to the towing vehicle. I will let it grow on me some more, if needed I could shave another 10mm off the total width by redesigning the frame. Each side of the frame can be pushed in 5mm when I adapt the shape of the frame to the shape of the treadway. For now I will run with this.

Next up is designing and making the hitch ...

 

[Arise0185]

Have you looked on McMaster.com? Should have just just about everything for your hardware needs

 

[Haastnooit]

Have you looked on McMaster.com? Should have just just about everything for your hardware needs

Thanks for the suggestion ... but I meant that I looked all over my shop . I have misplaced my M3 all-thread, I know I still have some but can not find it.

 

[Arise0185]

Thanks for the suggestion ... but I meant that I looked all over my shop . I have misplaced my M3 all-thread, I know I still have some but can not find it.

Gotcha!

Here's one idea for the trailer wheels - could you use shoulder bolts as your "stub axle," run it through a couple bearings that are pressed into your 3D printed parts, and then have a 3D printed hex that fits over the end of the shoulder bolt? And then nut to clamp down the wheel, of course. Maybe the hex isn't even necessary.

https://www.mcmaster.com/products/s...d-size~m3/metric-alloy-steel-shoulder-screws/

Just spit balling, it certainly doesn't look like you need assistance from the forum! You've inspired me to take on my own trailer build at some point... eventually...

 

[Haastnooit]

Today I worked on adding a hitch to the Patriot. Up front I thought this would be a lot of work because I thought it would be difficult to get to the frame rails of the truck and get good measurements. But it turned out the Patriot is really a Eazy RC … badaboom ! I could remove the rear bumper with 2 screws, loosen the rear of the body with 2 screws and finally remove the rear chassis brace also with only 2 screws to get full access to the frame. The body can be lifted out of the way … a walk in the park !

At first I always make a 2D plan to work out all dimensions and incorporate the measurements. From left to right, the chassis brace which goes in between the frame rails, in the middle top view of the hitch and on the right a side view of the hitch. Second step is to convert the 2D plan to a 3D model.

No prefabricated holes in the sides of the chassis mount part because I will drill the holes for attachement to the framerails freehanded, it is the most easy way for this part.

Printed part.

For a coupler I used a small rod-end, the eye will hook to a M3 screw (with 0.5mm thick sleeve) and the trailer will be secured on the hitch with a M3 locknut on top. Clearance between the hitch and the bumper is as tight as it can be while still able to remove and install the bumper when the hitch is installed.

I drilled the holes in the frame rails and chassis brace and secured the hitch assembly with 2 screws to the chassis. Really happy how this worked out.

Now all technical design and construction of the trailer is done, I will get to adding some detail. Next update I hope to have added the spare tire and ramps to the trailer …

See ya !

 

[Haastnooit]

Today I spend some time on adding details to the trailer to make it more interesting to look at. Off course the trailer has to be outfitted with some ramps to make it accessible for the power wagon. Here we go ... same steps again, from 2D to 3D, to actual printed parts.

I printed some drill guides to make installation on the trailer frame more easy, worked out great.

Next I made some brackets to store the ramps on the trailer.

Really happy with the outcome. Securing all parts with the tiny hardware does give it some nice detail and makes it look better in my opinion. I have thought about glueing all the ramp brackets to the frame, I am glad I decided differently.

Due to maximum pics per post I will update the installation of the spare tire later.

 

[Haastnooit]

Last item added to the trailer is the spare tire mount. I have looked at several different positions and decided I like the spare tire laying down flat on the triangle the most. So I made a mount to fit the triangle and also printed a spacer for easy placement and drilling.

I think the first part of the project, designing and building the trailer, is done. Although I just thought I might add some wheelblocks to the trailer ? Would be cool and adds more detail, so I will look in to this option in the upcoming week. After that focus will be on the towing vehicle. I am going to snoop around on the internet to get some free STL files of scale stuff to fill the roofrack and possibly the inside of the Patriot. Also will look in getting a scale driver.

Tommorow or the day after I will get some nice shots of the Patriot towing the trailer and show them in the next update ...

 

[Doom!]

The spare mount is a nice touch. Maybe add a license plate bracket?

 

[doolin64]

Just chiming in that this is a very cool build. I'm amazed at the quality of the 3d printer. Can't wait to see the next update.