~1:12 Miller Century M100 Rotator wrecker

[dremu]

I've always been fascinated by the tow trucks for big rigs. The biggest of the big is the Century M100 rotator crane truck. For instance, a coupla 1:1's:







These things are built to order, personalized bespoke items, and start at about a million and a half USD. When you're channeling your inner Tonka-truck-aged child, these things are pure cool.

So I spent a coupla years on and off trying to model one, started at the bottom. Those stupid outrigger legs were the death of me for the longest time. Even with a coupla segments telescoped, I could not get the legs to come out past the body long enough; they were way too stubby.

Eventually after looking at every photo Miller has posted and I believe all of their videos, I discovered the outriggers aren't independent left-to-right, which I'd assumed, but one block, with the left outrigger offset longitudinally from the right, so each can have the whole width of the truck. With that epiphany I was able to model nice long legs. (No ZZ Top jokes, please.)

Also found some relatively small, powerful, and inexpensive linear actuators suitable for use with Arduinos. Well, I say Arduinos, they're actually ESP32's, as the TX has been, ahem, slightly modified, and just uses WiFi to the motor controllers on the truck. Of which there are three for maybe 22 such actuators (I may have lost count), seven winches, three lightbars and in general more LED's than you can shake a stick at.

The CAD looks something like this



And the end result

[dremu]

Even with modified firmware, a traditional TX just won't have enough knobs & switches to control a beast like this. I opted, then, to graft an ESP32 and an array of switches and rotary encoders onto the back of my TX:





Left dial is for light mode, with two traffic directors (left-to-right and right-to-left, natch), a gentle orange hazard blink, and a seizure-inducing white and orange rapid strobe pattern. Clicking it changes brightness from attention-getting to truly blidning.

Right dial selects which legs will be moved in/out, the yellow LED's above indicating by quadrant. Clicking it resets to the default of all four legs. The red LED up top turns green depending on crane position, discussed later.

Like the 1:1, winch controls are color coded, because it's easy to get turned around when the crane is turned one way and the operator another. Is "left" "left", or "right"? This way the blue control moves the blue hook, can't get it wrong. You'll hear the operators say "Out on blue a bit", this sort of thing.

The other controls should be self-explanatory, save that I couldn't find a nice way to fit the word "Outriggers" on there and had to settle for "Legs." Which, again, she know how to use them, thank you Billy F. Gibbons.

Finally, said addition to the TX has one or two wires on it.



Since it's basically a metric butt-load of switches, the ESP has to rely on a coupla I2C expanders and there's just too many connections for me to even try and make a PCB for it. I just jumped point-to-point, but at least they're color-coded so I know what's what.

[dremu]

Outrigger design sorted, next up was the crane proper. It's much like the outriggers, telescopes, but has three actuators rather than two and lightening holes.



There's actually about ten feet of synthetic cable (err, nylon string) on each winch.

The base of it is this thing



I think eight pieces glued together. Primary and auxiliary winch servos go on the left, hinge for the crane on the right (when assembled, has brass bushings for the crane to ride on), and bolts down to the crane rotation mechanism via the four holes in the base. The big center one is clearance for the rotation mechanism, which is 608 skateboard bearings and an M8 bolt down through the crane transom.

The rotation mechanism is a big honking gear as base, driven by a tiny gear on a low-profile winch servo. Said big honking gear rides on more 608 bearings.



The orange thing is a rounded cover so the wiring harness doesn't snag.

[dremu]

One thing I discovered is that on many rotators, the crane doesn't just rotate, it slides. Yep, in addition to rotate, lift and extend, the dang moves about a third of the length of the truck. Makes sense, but it's a mess to engineer. You can sorta see the pistons of the actuators for that behind the top aluminum. As with the outriggers and crane, it's telescoping because there isn't enough room to fit a single stupidly long actuator. The rearmost one pushes or pulls a middle slider (here, white with a little blue toolbox thing, which later changed to black with no toolbox), which then chains to a second one which pushes/pulls the transom proper.



So it slides on aluminum angle, above the frame, marked "L." Here I'm working on wire management, because there are So. Many. Freaking. Wires in this build. If I never crimp another Dupont connector until the day I die it will be too soon. But I wanted it tidy and did eventually get it so. Hard to see, but above and to the left of the actuator for the tag axle is a black U-shaped thing. The 3D printers and CNC machines use it, call it "drag chain". Allows a wiring bundle or tubing or whatever to move in one dimension (this case, fore and aft) without moving in others (sideways or vertically.)

Eventually got the wiring mess tamed

[dremu]

Part of the reason there's so many wires is the ridiculous number of actuators and servos, but also lights. I like lights. A lot.

There's some spotlights by the winches



And then another wider beam pair at the end of the crane



They're just operated by your usual RC switch on an aux channel of the TX -- no need to overcomplicate and drive with the ESP32's. Another RC aux switch does the headlights and cab lights up front.

However, the turn signals and lightbars, that's where the Arduinos/ESP32's/whatever shine, so to speak. Programmable lighting means that color and brightness are changed in software. Turn signals are off and then blink on, unless the headlights are on, in which case they act as markers on and dim when blinking. Side markers are orange except the rearmost are red. Want to change something? Just change the code, the hardware stays the same.

Lightbar patterns are pretty much limited by your imagination, as the ESP32 has enough memory to do anything humanly possible, and the Neopixels are red-green-blue, so any color.

They are, however, fiddly to solder. This is one of three light bars with front and rear lines and then a single on each side.



Assembled, they look like this.



That's four pieces; the legs are one, top and bottom two more, and then a translucent frame for the lights to shine through.

The side markers are strung like Christmas lights, one into the next.



The one beef I have with the Neopixels is that a 5mm LED with four pins can be a pain to solder, especially when in close proximity, as opposed to strung like above. These are the rear turns and side markers.



The center two pins of the four are the hot and ground, so go from one to the next. The outer ones are "in" and "out", though, so the out from one has to go up and over to the in of the next, thus the diagonal crossover.

Cab lights are as on the Frobe, printed bullet housing with LED inside, running to RC switch on the headlights channel. Again, no need to overcomplicate.



LED is actually orange, so matches the translucent printed end.



And actual Tamiya horns again because why print and reinvent the wheel when they're cheap? Scale isn't quite right, but anybody going after my work with calipers will be beaten and disparaged.

[dremu]

Some examples of said strobe patterns:

Traffic director

Hazards

Full strobe

[dremu]

As always, the devil is in the details. Wreckers in general, and crane ones particularly, have to carry lots of tools, equipment, and accessories to cope with whatever situation they encounter. This in turn means lots of storage, alllll the way along the truck, as we see in the blue 1:1 truck above.

This meant printing a LOT of sideboxes and shelves, with hinges:



Color came out weird, but that's silver (ish) diamondplate for the top and a pull door handle, blue body, top and frame, and then dark blue door.

To snap the doors closed, I tried a little socket in the body with an arrow-shaped snap on the door:



That one's a fitment test; the final ones are blue to match the cabinets. They're still a bit tight, oddly, but they do snap.



If you look at the 1:1 up top, at one point there's an access area with flip-down steps to climb up onto the deck. These steps do flip, and have a stop so they only rotate down 90* and then stop. Like the storage box doors they hinge on unprinted (ie 1.75mm) filament, which is melted on one or both ends with a soldering iron to keep it in place. Fiddly, and you can see some boogers there that I hope I cleaned up afterwards. (Man, the camera really doesn't hide my oopses!

While most of the doors open sideways, some open up and the rear most set has both up and down, for reasons we'll see in a minute.



The rearmost cabinet bottom shelf houses the controls, a set each side. This would prolly have been better fabricated if I had any fabrication skills, but at this scale I don't. The Bambu printer at least did well with many colors and so I can color code here just like the TX.



That thing is like 1/2" tall, maybe 3/4" deep, and a few inches wide, so it's TINY. And took seven hours to print (but if you know how the Bambu switches colors you know why.) No matter, it's the best I could do and it's a fun detail.



Long shot showing all the boxes.

[dremu]

Now, what to put in the boxes? I opted to take some guidance from the 1:1 above, which I'm sure is a Miller showcase of everything they sell and not necessarily a realistic example of an actual truck. A good start though.



Front has a printed rack to hold a variety of shackles and sheaves, courtesy of AliExpress. Ignore the blue tape on the left, holding in the door handle whilst it dries.



This one holds various underlift attachments. While the underlift and chain attachment proper are modelled on the real article, the axle attachments are made to fit the various axles and kingpins on my trucks and trailers, so the thing can actually pull the Frobeliner. This really is why I made the Frobe ... so I can justify a tow truck to pull it =))



Getting ahead of myself though.



Other shelves hold straps, gotta have straps in different lengths. These also date back to when I made the HEMTT, and are ribbon from the craft store, hotmelt, and heatshrink.

I do not like hotmelt.



This is a printed rack to hold chains, again, AliExpress. There was a time seemed like I was getting tiny packages from China on a daily basis.



Another shelf has endless straps, aka hair scrunchies from Walmart. Didn't have to go to China for those. Obvi since they stretch they're just for looks, but a man's gotta accessorized his truck.



Did have a devil of a time making chokers though. Tiny wire rope and crimps aren't a problem, comes with the winch servos and I'd switched them out to synthetic (the aforementioned nylon string.) But finding thimbles for those was a challenge. They don't need to be structural, but they're too small to print (I tried.)

Eventually found some on McMaster which worked, with a little bit of trimming. Of interest was the fact that McMaster emphasized the ZERO WLL NOT FOR STRUCTURAL LOAD BEARING. I mean, at that size, dafuq?



And a combination of printed parts and music wire from the hardware store, and they can mount up under the crane as on the 1:1

[dremu]

As we know from the HEMTT, I tend to make my builds my way, mixing and matching, but since these trucks are bespoke in the real world, this one doesn't so much take liberties. There are some places I had to fudge because the actuators used only come in certain sizes, etc, but I'm hopeful that if someone from Miller looked at this they'd immediately say "Yep, that's an M100. Bit small, but that's one of ours." =))

Anyway, I like me my diamondplate, and that red truck above has front fenders I like, reminds me of a railroad engine.



Printing diamond plate with the Bambu isn't bad, but drawing up the bi-color striped pieces was a challenge. Also has to fiddle with it to make the stripes line up as you go around the corners, and then bevel the insides so they can all glue together nicely.



Front grille has the Kenworth logo, came out okay given that it's scaled down so tiny.



Because diamondplate, and because multi-color printing. Note the auxiliary winch hook on that side is yellow, vs that on the other side is black.

[dremu]

Other random bits. Front axles are limited and ratio'ed by a baby Arduino (blue in pic), ie the frontmost turns more than the second.





Drive is only to the rear two axles. There's also a tag axle which is a Chinesium Tamiya-type trailer axle, split with a printed U-shaped center to clear the driveshaft.

Motor is your basic 540 type, 90T, with a 4:1 planetary reduction on the end of it. Could prolly use a bit more even.



Of course, this means there are three different tire sizes: fronts are super singles, rears are regular duals, and the tag is a bit smaller to clear when lifted. The tag also took a printed center hub since it's a single and the wheel faces the opposite direction to the rear duals and none of the ones I had fit right.

I've taken to using the Chinesium metal wheels since they're cheap and look nicer than the printed ones I used to do (though for the military trucks with beadlocks and such, still gotta print.)

[dremu]

Further indication of So. Many. Wires.

Inside the cab, one ESP32, with two DRV8833's for the underlift and a bunch of jumper points for the lightbars, and the ESC for the motor (you mean this truck also has to DRIVE??)



Under the front deck



Two more ESP32's, one with two DRV8833's, one with three, for the crane and its lightbar and outriggers and the deck winches and tag and whatever else I forgot.

There's a lot of stuff, like the crane transom has an opto-detector that tells when it's slid forward and can only rotate a little bit, so it sends that signal to the TX which then lights up a red LED by the crane rotate switch. Once the transom slides far enough back, that LED turns green so we know we can fully turn.

[dremu]

A selection of accessories for the discerning recovery crane operator.



Outrigger pads, printed in TPU,



But also various attachments for the underlift, including the center one (red) for kingpin attach, narrow and wide straps, various shackles, bungees, slings, fire extinguisher, wheel whocks, coupla pieces of drayage (okay, lengths of square dowel ) and the short spreader bar. There's also a long one, to prevent squishing irregular loads when rigged. The spread bars are metal tube with printed ends and so far held up to the load of the conex. Wouldn't trust a printed round that long though, plus metal is cheap at the hardware store and looks better.

By the by, I greatly enjoy Pepe's Towing YouTube channel. Josh can explain the spreader bar far better than me.

Also printed up extension ladders in sizes



Because the stepladder I made was beautiful, but didn't scale down for squat.



Also got to use some of the many, many cones I made for the HEMTT.



I think I made like eight or ten in each of a half dozen colors, got a bit happy. But I like cones. Handy around the house even:

[dremu]

Finally, while a lot of tator operators use them purely for recovery and have a dedicated truck for towing, I wasn't gonna build a second truck just for the underlift. I have finite shelf space and spent however many bazillion hours over years to do this one and don't want to do another, so dangit, I can have an underlift on it if I want one (which, again, is like the 1:1. If you have the budget, Miller will build it for you.)



This is one of those places where I had to fudge to make it fit the actuators and whatever I had to work with. And my putting in two rear deck winches, because Go Big or Go Home. (Plus it really wasn't any more work to fit two than one since they're mirrored side-to-side.)



But it lifts, extends and folds like the 1:1.

Hero shot with one set of axle adapters installed



Up close. There's also offset round axle adapters, coupla kinds of square ones, etc, for all the different axles I have in use. Still gotta do frame hooks, and am working on a kingpin adapter to tow trailers.



As teased above, towing the Frobe. Waiting for nice weather to get outside and do this on the tarmac as my table, impressive though it is, doesn't allow for much towing.



And threw together this detached lightbar to put on the casualty under tow, hooks to the back of the wrecker. It's just turn signals and brake, no strobe patterns.

Phew, think that's it. Been a heck of a long time coming, and already I'm thinking of new projects, doh.

[Blender]

Very nice build. That is a lot of custom electronics. Is everything connectorized to get it reconnected in the right spot, or are most jumper wires that need to be correctly placed?

[dremu]

Originally Posted by Blender

Very nice build. That is a lot of custom electronics. Is everything connectorized to get it reconnected in the right spot, or are most jumper wires that need to be correctly placed?

Thanks, yeah, tons of electronics, but that's something I enjoy. Mostly.

Not sure I follow the Q. Each board has plugs on it, color-coded and the wiring harnesses are color-coded, either by wire color or short lengths of colored heatshrink, so as to identify them.



Right-hand side of the ESP32 boards have alternating red and black headers which are outputs to the various actuators. Yellow and blue jumpers go from the DRV8833 motor boards to the ESP's; there's also green and black which is motor power that go to a power distro board up under the hood, regulated power. Yellow and black pairs are switched straight off the battery and go to a 7805 on each board.

That leftmost ESP board has red, green and blue-tagged wires for the underlift, and then at the bottom, behind the anodized red ESC and its larger drive motor wires, is a row of red-white-black headers for the Neopixel LED strings. Looks like at this point I only had a couple, the white and purple ones, whatever they are.

Rather than hard-solder anything, the ESP sockets have a male header next to them which is soldered straight across; that's what the blue, yellow, etc goes to. Those then can just use off-the-shelf short pre-made jumpers in many instances, repinned into larger Dupont shells.

And yeah, this was early on where I'd cut the wires too long before stringing them for good, and I ended up having to trim them and re-crimp. Did I mention I'm tired of crimping? =))

[ddmckee54]

That's a nice looking beasty.

Having designed industrial control systems for half of my 35 years as an electrical engineer I can feel your pain about the wiring. Neat wiring is a good thing, but everything working correctly when all the doors are shut is better. The first time somebody needs to make a hurry-up-quick repair, neatness is usually tossed out the window.

It looks like you've got your printer dialed in pretty well. What do you normally use far your nozzle width and layer height?

Don

[Zabco]

That is an absolutely incredible piece of work. Very well done! Approximately how long did it it take to put all that together? Those big heavy rescue wreckers are one of my all time favorite trucks.

There is an old truck and equipment show held every year near where I live. Several years ago a nearby heavy recovery company brought in three of their big rotators and demonstrated how they would lift and move an overturned tanker trailer. It was an amazing demonstration. Their booms were not as big as the one you modeled (2-40ton and a 50 ton boom). And expensive!!! Asked the owner what one of those trucks cost and if I remember correctly he said the most recent one was $1.2 million. In 2017 dollars.

Again, congrats on the beautiful build.

[dremu]

Originally Posted by ddmckee54

That's a nice looking beasty.

Having designed industrial control systems for half of my 35 years as an electrical engineer I can feel your pain about the wiring. Neat wiring is a good thing, but everything working correctly when all the doors are shut is better. The first time somebody needs to make a hurry-up-quick repair, neatness is usually tossed out the window.

It looks like you've got your printer dialed in pretty well. What do you normally use far your nozzle width and layer height?

Don

Thanks! I started out on a track to become an EE, got sidelined into software, but always enjoy electronics as a hobby. Which might be obvious her e=))

Wrt the printer, I'm on my fourth printer now. Makerbot, FlashForge, Qidi ... and the Bambu. I tell you, the Bambu Just Works. I'm a lifelong Windows guy; it's evil, yes, but the evil I know. PITA to maintain, but I mostly grok it.

Conversely, Bambu is like a Mac or an iDevice. It knows what you want and it does it. Yes, it's expensive and a closed ecosystem and works best with their filament which isn't cheap either. But it always Just Works. (Almost always anyway. I've had maybe twice the prints warp. A little glue stick on the print bed, boom.) Also fast as ****. And the AMS is fantastic, can do as many colors as you'd humanly need. Yes, it wastes some switching ("pooping"), but with careful planning of the part this can be minimized. The bumpers with the silver body and translucent turns and brakes and such -- see my Frobe and trailer threads -- are perfect examples of this.

To be specific, I almost always use a 0.4mm head and 0.2mm layer height. For the license plates the detail requires I use a 0.2mm head and 0.1mm layer height, which means it takes TWO FREAKING HOURS to print a thing that's what, 20x30mm? To be fair, it takes about the same time to print two as it does one as it's all the color switching that takes the time.

[dremu]

Originally Posted by Zabco

That is an absolutely incredible piece of work. Very well done! Approximately how long did it it take to put all that together? Those big heavy rescue wreckers are one of my all time favorite trucks.

There is an old truck and equipment show held every year near where I live. Several years ago a nearby heavy recovery company brought in three of their big rotators and demonstrated how they would lift and move an overturned tanker trailer. It was an amazing demonstration. Their booms were not as big as the one you modeled (2-40ton and a 50 ton boom). And expensive!!! Asked the owner what one of those trucks cost and if I remember correctly he said the most recent one was $1.2 million. In 2017 dollars.

Again, congrats on the beautiful build.

Thanks for the good words. Time-wise, been drawing this up for a coupla years on and off, lot of off. Actual assembly, few months. Joy of being semi-retired. Once I had a plan it's not so bad, other than having to reprint bits when I found problems, which happened more than I'd like, or restring the wires for what seemed like the 300th time.

I watched a LOT of recovery videos, such that my wife got to leaving the room, bored her out of her mind apparently =)) But the physics of it, where the tator picks up these immense loads, whether busted semis or trailers in precarious positions or cut in half by a train, or weird transformers or precast concrete or whatever, truly amazing.

And yeah, this particular tator I think starts about $1.5M now and the sky is the limit. They also build 'em on three-steer-axle chassis, which I'm glad I didn't see until I'd got my chassis done or I would have gone nuts =))

[frizzen]

Beautiful truck!!!

I'm amazed at how many features you were able to replicate, to get all af that working together.Then still having room for working accessory boxes, and filling them with equipment

I'm really digging all that extra functionallity you added into the radio, plus all the features you're able to use, should be amazing to watch in operation.

Good thing you modeled the 100 Ton unit, it might take that much to get my jaw off the floor!