Build Thread 1:12th Scale Rollback Truck Ideas

[James A. Doty]

I posted a message very early this morning in the Electric RC forum about wanting to build a rollback truck in 1:12th scale.

I found a nice set of STL files to work from and resized them larger by 35% so they'd be right for 1:12th scale and printed all the plastic parts I need. I'm reprinting the two piece load bed though, I didn't care for the print quality of the first two. I should have the second half of the load bed complete sometime today.

I was warned not to use servos to run the winch, move the bed forward and backward, and tilt and untilt the bed. Electric motors would be better suited. Is there an adapter/controller I can use to run those three motors using receiver channels? I didn't some research and didn't find anything, though I admit I may have been searching for the wrong item(s) by name.

I think I'll use an MN82S as the donor truck. I'll need to cut the chassis in half and remove the flat bed and box from the back of the cab. I can 3D print chassis rails to splice in.

I don't know how long this project will take or if I can even pull it off. I was inspired by the MN82T and thought to myself that adding a rollback truck would be a cool choice.

I have an MN82T on order.

 

[CertifiedMike]

I posted a message very early this morning in the Electric RC forum about wanting to build a rollback truck in 1:12th scale.

I found a nice set of STL files to work from and resized them larger by 35% so they'd be right for 1:12th scale and printed all the plastic parts I need. I'm reprinting the two piece load bed though, I didn't care for the print quality of the first two. I should have the second half of the load bed complete sometime today.

I was warned not to use servos to run the winch, move the bed forward and backward, and tilt and untilt the bed. Electric motors would be better suited. Is there an adapter/controller I can use to run those three motors using receiver channels? I didn't some research and didn't find anything, though I admit I may have been searching for the wrong item(s) by name.

I think I'll use an MN82S as the donor truck. I'll need to cut the chassis in half and remove the flat bed and box from the back of the cab. I can 3D print chassis rails to splice in.

I don't know how long this project will take or if I can even pull it off. I was inspired by the MN82T and thought to myself that adding a rollback truck would be a cool choice.

I have an MN82T on order.

I should have been clearer. Do the files ask for a servo or do they ask for motors to be used?

While I am not super tech savy with these, stepper motors and arduino(?) may get you control and power.

There are plenty of servos that should be able to rip the bed right off your chassis.
The issue is size.

How is the truck designed?

 

[James A. Doty]

I should have been clearer. Do the files ask for a servo or do they ask for motors to be used?

While I am not super tech savy with these, stepper motors and arduino(?) may get you control and power.

There are plenty of servos that should be able to rip the bed right off your chassis.
The issue is size.

How is the truck designed?

The STL files call for very small motors. Since I scaled things up 35% I'll have to print motor spacers to get the motors to fit properly but that's no problem.

I haven't played with Arduino boards enough to know what I can do with them, though I know they can control DC motors. I don't know though how to control Arduino boards using receiver servo ports, at least not yet.

It might take some current sensing to prevent the motors from ripping the plastic parts to shreds.

 

[CertifiedMike]

I think servos might be the better choice too actually. Its about space but you shouldn't need massive power for 1/12 scale.

I was picturing micro servos going in the bed. I think thats too small but a pair of reg sized servos with decent specs will work as long as you can squeeze them under the truck somewhere.

 

[James A. Doty]

Maybe I should start with the MN82T as the donor truck instead of the MN82S since It comes with a winch and controller? That would be one less thing to worry about.

 

[CertifiedMike]

Be sure that the winch and controller can be swapped into your conversion or that it can be easily unplugged and replaced with a more suitable winch servo.
I think an aftermarket radio system will offer much more control and adjustability per channel than the rtr system.

Does it have enough channels to control the roll and tilt servos too?

 

[James A. Doty]

Be sure that the winch and controller can be swapped into your conversion or that it can be easily unplugged and replaced with a more suitable winch servo.
I think an aftermarket radio system will offer much more control and adjustability per channel than the rtr system.

Does it have enough channels to control the roll and tilt servos too?

Yeah, I'll have to go aftermarket for the receiver. I suspect I'll need at least a six channel receiver, which means I'll have to find a six channel transmitter as well. I'll go with a stick style transmitter for that, steering wheel and trigger style transmitters can get awkward with that many channels.

 

[CertifiedMike]

If you are into tech, the Radio Master MT12 is trigger but you can add switches, knobs... Its super flexible, user programmable, and inexpensive, not cheap.


It has a steep learning curve. There are plenty of vids to help you get thru.

They offer stick radios too. I know nothing about them tho.

 

[James A. Doty]

Be sure that the winch and controller can be swapped into your conversion or that it can be easily unplugged and replaced with a more suitable winch servo.
I think an aftermarket radio system will offer much more control and adjustability per channel than the rtr system.

Does it have enough channels to control the roll and tilt servos too?

I purchased another MN82T this morning, I'll use it for the chassis, the cab, and the winch. If the winch works out maybe I can find two more to add to the build.

I'll have to find a way to couple lead screws to two the servos for the bed functions.

 

[James A. Doty]

If you are into tech, the Radio Master MT12 is trigger but you can add switches, knobs... Its super flexible, user programmable, and inexpensive, not cheap.


It has a steep learning curve. There are plenty of vids to help you get thru.

They offer stick radios too. I know nothing about them tho.

I checked into the RadioMaster MT12 4-in-1, I think we have a winner. I'm good with high tech gadgets. I worked in the IT field from 1995 until 2024.

I bought the MT12 4-in-1 version and an eight channel R88 V2 receiver.

My two piece flat bed has finished printing. I had a small part I was printing along side it, but I think it came loose from the bed. I'll clean the bed, and add a bit of bed glue and reprint that part. I can't use the original part because it's currently CA glued to my test chassis, but I can reuse all of the other parts I printed.

 

[CertifiedMike]

I checked into the RadioMaster MT12 4-in-1, I think we have a winner. I'm good with high tech gadgets. I worked in the IT field from 1995 until 2024.

I bought the MT12 4-in-1 version and an eight channel R88 V2 receiver.

My two piece flat bed has finished printing. I had a small part I was printing along side it, but I think it came loose from the bed. I'll clean the bed, and add a bit of bed glue and reprint that part. I can't use the original part because it's currently CA glued to my test chassis, but I can reuse all of the other parts I printed.

I have heard good things from everyone who owns an MT12. I think you made a wise choice.

 

[James A. Doty]

Except for designing and printing a servo operated winch, I have the bed complete. My next step for the bed will be to paint it. I'm using Bambu Lab PLA for this project.

I'm considering printing support pieces to glue under the bed for added strength. Though the two halves are glued together at the seam and gluing tabs under the bed, plus the side rails overlap at the top and are glued to each other and the bed surface.

I'll be at a pause in the build while I wait for the donor truck to arrive. I'll need to cut the frame in half then design and print new frame rails. I'll order a roll of Bambu Lab black ABS for that task.

I got the designs from bishopdq on Printables then enlarged them by 35% to suit my needs.

 

[CertifiedMike]

The bed looks very much like I remember from years ago.
Very cool!!!

 

[WickedFog]

Watching!

 

[James A. Doty]

Watching!

I'm running a test print on a cab idea and starting to generate some CAD files. I have some RC stuff coming for the build as well.

 

[WickedFog]

Bed looks great so far.

 

[James A. Doty]

I think I've settled on a cab for the truck. This was a draft print so it's not pretty. I'll print the final body in ABS. The body will be red, the door handles, headlight rings, locks, and the grille work next to them will be silver, and the window trim will be black. I'll print the front bumper separately in either black or silver. I'll print the headlights in clear PETG.

I don't know how to do windows, I'll have to look that up. I think I can mock up an interior without too much trouble.

I think I'll have to decide on if I need to scale the cab down just a bit, I think it looks a bit too big.

I'm about half way through designing the slide servo mount.

 

[CertifiedMike]

I think I've settled on a cab for the truck. This was a draft print so it's not pretty. I'll print the final body in ABS. The body will be red, the door handles, headlight rings, locks, and the grille work next to them will be silver, and the window trim will be black. I'll print the front bumper separately in either black or silver. I'll print the headlights in clear PETG.

I don't know how to do windows, I'll have to look that up. I think I can mock up an interior without too much trouble.

I think I'll have to decide on if I need to scale the cab down just a bit, I think it looks a bit too big.
View attachment 273252
I'm about half way through designing the slide servo mount.

That cab is GREAT!!! You should keep that one and build a weathered, 'junkyard hauler' version to go along side the 'clean' build.

I love that cab!!!

 

[James A. Doty]

That cab is GREAT!!! You should keep that one and build a weathered, 'junkyard hauler' version to go along side the 'clean' build.

I love that cab!!!

Once the "clean" cab is printed maybe I can do something with the rough draft cab. I love '60s era Ford Econoline trucks and vans. Of course Ford never made an Econoline truck with a flatbed or a rollback bed, their largest available engine was a straight six 240 cubic inch gas engine.

Over the years both my dad and my sister each had an early 60s Ford Econoline cargo van, I don't know which engines they had but I loved them both, they were cool vans. My dad totaled his in 1978, my sister abandoned hers along Highway 14 in Vancouver, Washington a few years later.

I've owned four third gen Ford Econoline vans since 1979 and now own a fourth gen Ford Econoline as my backup van incase my Town & Country or the wheelchair equipment needs repair.

 

[James A. Doty]

I finally have a slide servo mount I can live with.

I will put a dab of CA glue on the servo to hold it in place, though the M5 threaded rod going through the hole in the front of the mount would prevent the servo from coming out.