jebster's tonka truck rc conversion

[jebster]

Originally Posted by Djcrabt

Very cool conversions.

thanks. something different than scale trucks to give me some challenges

Originally Posted by Mike Flea

You're going to have the Tonka Construction Co. complete soon. Still need the Road Grader and the Crane yet .

Great job on the Crawler , works well even with the wobble.

road grader is an option, although i noticed it is smaller than the other rigs. pretty straight forward to convert to rc, although i might want to make a challenge and have the front axle a drive axle. that would be a LONG shaft from the rear.
the crane is another one i've been looking at. i have ideas on how to convert but the problem is to make everything work would need 5-channels and i only have 4-channel radios. i could get a couple extra functions if i used a heyok style remote control. we'll see.
one last tonka rig i saw is a mixer truck. maybe...

[jebster]

Had some time a couple weeks back to get all the rigs out to play. Took a video of them in action.

https://youtu.be/d4qyRrBsB-g

[Steve g]

Man they look too good to get dirty. Do you think a couple of pounds of weight in the rear of the loader and the bulldozer would help them move the sand better, or cause them to sink in and bottom out more?
Anyways nice builds.

Sent from my SAMSUNG-SM-G920A using Tapatalk

[Mike Flea]

Need to take them to the Cabin Fever event in January, Home, and run them on the dirt pile

I wonder if you put a bit more weight down low on the bulldozer, if it would help with traction, or add some metal strips to the tracks.

[jebster]

Originally Posted by Mike Flea

Need to take them to the Cabin Fever event in January, Home, and run them on the dirt pile

I wonder if you put a bit more weight down low on the bulldozer, if it would help with traction, or add some metal strips to the tracks.

Originally Posted by Steve g

Man they look too good to get dirty. Do you think a couple of pounds of weight in the rear of the loader and the bulldozer would help them move the sand better, or cause them to sink in and bottom out more?
Anyways nice builds.

Sent from my SAMSUNG-SM-G920A using Tapatalk

Sorry, haven't checked in on this thread in awhile.

I agree with both of you that adding some weigh to the bulldozer is a good recommendation. overall it is pretty light so it probably isn't putting enough pressure on the tracks. I like the idea of adding some metal strips to the tracks but I have to see how that can be done. not a lot of clearance between the tracks and linear actuators on the blade right now.

looking back a the video makes me think the loader could also use a little more weigh to get better traction.

I have so many more Tonka vehicles I want to convert, just too little time given all the other projects on the bench!

[Mike Flea]

[jebster]

Been busy with other projects but thinking about doing another Tonka conversion. This time I'm thinking of doing a scraper.

For the drivetrain I'm thinking about some robotics motors with a chain system to drive the axles. It will be 4 wheel drive. Going to use a screw drive system to operate the scraper bucket adjustment. For steering I'm looking at a servo mechanism. Maybe I have an excuse to pick up the new Holmes v3 servo!

I have some measurements to do before the real work starts but I'm getting excited for this.

[Mike Flea]

Looks like it'll be another great project!

[Stormin2u]

Great projects jebster!!! It's fun to see them restored and made RC capable. I couldn't have imagined such a thing being possible as a kid playing these same toys. ...

[jebster]

Originally Posted by Stormin2u

Great projects jebster!!! It's fun to see them restored and made RC capable. I couldn't have imagined such a thing being possible as a kid playing these same toys. ...

Originally Posted by Mike Flea

Looks like it'll be another great project!

Thanks. And I agree that 40+ years ago I would have never imagined having my Tonka vehicles actual run.


I did start the deconstruction of the scraper to start the modifications. Looking it over I think I have all the mechanics in my head. The one challenge is the pivot between the cab and the rest of the rig. What I need is a metal cross which allows it to both pivot and rotate. I drew a rough schetch of what I'm thinking. Since I don't have welding capability (I do brazing but I don't think I could make this strong enough) I need to see if I can find someone to fabricate this up.

[JatoTheRipper]

Making some progress! Looking forward to seeing it move.

[jebster]

Originally Posted by JatoTheRipper

Making some progress! Looking forward to seeing it move.

It is moving forward. Made up mounting plates that will support the drive motors and axles. Started on my steering setup. Looking forward to seeing if the new Holmes servo has enough power to swing this rig around.

I'm at the point I need parts to get more done. Primarily I need the sprockets so I can place axle to motor spacing but those are inbound from China. It may be awhile!

[jebster]

Got more work done. Drilled the axle plates and mounted up the drive axles and bearings.

Got the scraper mechanics figured out. Mounted a motor with a gear reduction that drives a screw drive rod. As it turns it moves the level from dig to dump.

I started on the main pivot point. The back will rotate on the large upright rod. The smaller horizontal rod allows the front to tilt right and left. I think the setup will work fine.

[jebster]

Continuing to make progress. Getting the primary pivot point set up and preparing to make the steering work. The shocks will actually be locked to a fixed length to act as drag links. The mock up is looking like it will work out fine and won't interfere with the twist and pivot motions. Once I get the shocks locked to length I'll be able to do some testing to see if the Holmes v3 servo has enough torque to make the rig turn.

[jebster]

First test of the steering. Seems to work although I still have a lot more weight to add to the front which could challenge the servo.

https://youtu.be/GmMddqv_fNM

[jebster]

Got the parts in to get the blade mechanics working. I'm liking how this is turning out.

https://youtu.be/TT4kHWmyS5s

[Mike Flea]

Wow, that's pretty cool. Good job

[jebster]

So, given I'm waiting on parts to finish the drivetrain on the scraper I decided to start in on my next conversion: the mighty crane!

I had parts on hand to do the crane rotation. Basically a large aluminum spur and pinion I got from servo city. I got them installed and did a quick test to see that it works. So far so good.

This one will be interesting in that I will need a couple winches. One to raise and lower the boom is pretty straightforward. The winch to operate the bucket need a to be special. It needs to be able to lift and lower like a normal winch but I need to have a servo operated free spool so it can drop the bucket quickly. I have a plan to convert a 2 speed transfer case to have a free spool option by removing the high speed gear.

https://youtu.be/oykPgrl_AmE

[jebster]

Originally Posted by Mike Flea

Wow, that's pretty cool. Good job

Thanks. I find these conversions fun builds. No cookie cutter parts here. Everything has to be custom and thought out.

[17dean]

Watched Youtube video of its flawless movement. Awesomeness as usual.