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Snowball
The little mover that could.
Eventually...

I've been moving trailers for over 45 years now. I was fourteen or so the first time someone said "go move that thing" and tossed me the keys to a pickup truck with a boat behind it. I think it was purely for entertainment of my friend's father to watch me, who doesn't have a driver's license yet, try to figure out how to move this two wheeled cart that wants to go anywhere other than where I wanted it to. Over the years I've had some adventures with trailers. Everything from learning about how if you don't grease bearings you end up spending hours with a hammer, chisel and swearing to watching the guy in front of me loose a wheel on his boat trailer to having a load shift and discovering what weaving from behind is like (SCARY!). I've cut corners too closely causing body damage, I've turned too sharp, poking holes in the front of the trailer with the van's bumper, I've had two wheel, four wheel, fifth wheel, light and airy, big and heavy, flat with rails, boxed with car moving stuff - lots of experience with them. I've probably towed a trailer across the country more times and farther than many have even driven. Yeah, I'm used to being followed. A couple of months back (June of 2005) I decided that it was time to sell my trusty old Sterling box van. After nineteen years of service I was ready to downsize and change a few things. We got a new Ford F250 Super Duty which is a pulling monster. That lead to getting rid of our Lance Toy Hauler and me using my twenty foot box trailer as my primary mode of transportation for the bikes, the shifter kart and my car on track days. The trailer has lived outside for the past eight years or so. Time for it to come inside and enjoy a life in the shade instead of the brutal AZ sunshine. It didn't take me long to realize that using the pickup truck to move the trailer from the RV side of my shop into the work side was kinda a pain in the butt. The trailer is wide (8' 6"), the shop entry is kinda narrow with some benches and a set of stairs just inside the garage door. The lighting is also a bit of a hindrance. From bright sunshine to shaded (or well lit, depending on how you look at it) and I have to back it in at an angle. It would be so much better/easier if I could just move the trailer "by hand" between the two bays. That got me thinking and the gears in my pea brain spinning which generally tends to be a dangerous thing. I've seen trailer movers. Some are just a stick with a ball, handle and wheels. They work just fine for a PWC or two rail dirt bike trailer. I've also seen a mobility cart with a hitch attached to the front for moving smaller stuff but I've never seen anything for a larger trailer like I have. A bit of Google-fu and what do ya know, there are all sorts of trailer movers out there. From the simple ball and stick to self propelled, remote controlled units. That got my pea brain shifting gears "oohhhh, ahhhhh, that's cool". Words I should never say.

Park It 360 has some really interesting units. They also have some VERY EXPENSIVE items.

Basic Unit

Basic Motorized Unit

Bad Ass Mover

Majorly Bad Ass Mover

I watched a few YouTube videos on movers and decided that I could make my own, after all that's what I tend to do as I like making stuff. Down the rabbit hole I went.

Let' see. Shopping list time. What do I need? I need drive train stuff, I need batteries, I need controls. Amazon is amazing as you can find almost ANYTHING there.

First thing was the drive train. What can hold up 500 pounds, is electric (24V) and has a differential? Mobility scooters. I've seen this done. A bit of time searching for mobility scooter drive train and I have a trans-axle that uses a 24V motor. Perfect.

Speed controller - yup, more Amazon stuff.
Oh and what's this? An electric hydraulic jack? Add that to my cart, "click". Search again here's a set of caster wheels that can handle 1,000 pounds. "click" I'll need some switches and this part and that part. Click, click, click add to the shopping cart. I'm now into this about five hundred bucks which is drastically less than a store bought unit. My good friend Jay also happened to have a couple of 24V LiPo batteries out of an old mobility scooter sitting on a shelf. I told him what I was up to and he said "Here, don't order batteries, these will work just fine." SCORE! Jay's place is where I got the mobility cart idea from. It's what they used to move their stuff.

I liked the layout of the Basic Motorized Unit that Park It 360 has. Simple, looks easy enough to copy but it needs a second set of wheels. I know it's going to torque over when I put a load on it. I had my vision now.

Time to start getting things laid out.

The Motor-Totor was in it's infancy. Parts scattered about my work bench, sharpie marks all over the top of it and a plan of wing it and make it was laid out. I'll put the ball lift right in the middle of the frame for weight distribution (there was something sitting on my shoulder saying "That jack is going to stick up a bit and raise the center of gravity, this isn't gonna work." but I didn't listen), the casters on the ends of extending arms, the mobility drive train (MDT from now on - less typing) under the back and the batteries will hang underneath the frame.

I knocked out the frame, got the MDT and casters mounted and with a quick check said "Yeah, this ought to work". It fit under the trailer tongue nicely and looked like it was going to have clearance between the casters and the tongue jack to move around without interference. I raised the jack on the trailer and the Motor-Totor held up just fine. Good, that works out.

Back up on the work bench (quite easily right now) with it to make a control handle and install the electronics. The pair of 24V LiPo batteries were hanged under the frame up against the MTD out of the swing of the caster wheels and the speed control was wired in. Not mounted, but functional. I can't do anything "simple". I had to put brass bushings in the handle pivot make a stop so it can't fall farther down than I can reach - remember, this is a lazy person's machine. Heaven forbid I have to bend over to pick up a handle. It pivots oh so smoothly. Motocross grips that just clamp on (ORI grips are great - use 'em on the dirt bike) were spec'd too. I've ridden bikes too long - if I have handles to drive something they need to be wrapped in motocross grip.

I put the Motor-Totor on the ground, turned a knob, flicked a switch and what do ya know! The Motor-Totor moves on it's own. That's pretty cool. Second step in proof of concept was checked off.

More motor testing was needed. I've got the thing wired up and working albeit none of the controls mounted yet. I have a flat space on the top of this thing, I have a spare karting seat and I have an idea. This thing zips around surprisingly quickly! Flip flop friction was required for steering control.

Now it was time to see if the Motor-Totor was capable of anything other than scooting my ass around the shop. I guided it under the trailer and put the trailer jack down on it. Let's see if it can move the trailer. I turned on the controller, pushed the forward button and started dialing in the speed (weird how these mobility carts are wired for control). The motor grunts, I hear what sounds like electrical straining, the speed controller's making some bad electronic noises, the trailer kinda moves, maybe... Pffftttt. Out with the magic smoke. The controller has given up the ghost. Kinda wondered if I'd picked a controller capable of the load. Obviously this little 20A unit is not but then again it was eighteen bucks on Amazon. Time to look at other controllers (ordered a 60A). I'll get the jack mounted while I wait on a new one.

"You’re now qualified to shop at Walmart." - quote from a friend after seeing the video.

As stated, the Motor-Totor is a lazy man's machine. Why work harder when you can work smarter, right? I'd found a 24V hydro-electric jack that was low profile and more than capable of picking up the trailer. It has a fairly small footprint and is pretty inexpensive too. Push a button, the lift extends, push a button, the lift withdraws. Neat! I got busy pulling it apart so I could get it mounted to the frame and access the control electronics.

My only issue with the jack is that it has a platform and not a ball on the business end of the lift. The platform is going to slip. It's on the end of a fairly long piece of threaded shaft. No big deal. I'll just unscrew that out of the jack and then machine threads on the 2-5/16" ball I have and replace the platform with a ball. Or so goes the plan.

Turns out that the threaded piece has some sort of stop that won't let you remove it. Disassembly time to see what's up. I was going to have to pull it apart anyhow to do the wiring. I looked at the bottom trying to see if there was some sort of stop. Nope. Crap. Time to get creative. Out comes the cut off wheel and off goes the top part of the threads. I chucked the ball into the lathe and got busy removing metal. By the time I was done I had a ball with a short neck that threaded perfectly on the piece I'd just cut off of the jack so I knew it would thread right on the end left in the jack.

Time to pull out the electrical engineer in me and start wiring things. The motor has direction and speed controls and the jack has up and down. Wires were run, I tucked away control a knob, power switches and a battery power meter in a box and mounted that to the bottom of the handle. Everything at an easy reach. I'd also received a new speed control so that got stuck to the frame of the Motor-Totor between the batteries and the MDT.

I grabbed hold of the Motor-Totor, picked it up off of the bench and sat it on the floor. Gee, it's gotten heavier. Once again, time to flip switches and spin knobs and see what the thing can do with the new speed control and jack installed.

The jack is being picky. It works for three to five seconds and shuts down. I'm not sure what's up. Did I get air in the hydraulics when I pulled the plate off of the bottom to mount it to the frame? No, that doesn't make sense. There are no lines that go to the hydraulics other than the two motor leads. Weird. Snowball is being Snowball. I get in touch with the company I purchased the jack from and they're quick to answer (great customer service). "Is it getting 24V?" Yup, there's power from a pair of 24V batteries running to it. I've pulled the stock battery lines and wired them straight to the power lead in the system. I'll dig into this later. I can cycle the power to the jack with a flip of a switch and get it to work albeit it's a pain in the ass. It's supposed to just run. Does the same thing in both directions too. Weird.

I drove Snowball to the front of my trailer, set her in place, hit the jack lift button and as it engaged the jack grunts a bit. The trailer tongue comes off it's pad, the Motor-Totor does it's little squat and I hit the reverse button. I've got the speed control set about 30%. It grunts a tad and then tries to move the trailer. Nope, not yet and something says this isn't going to work. It's going to overload the system. I turn the speed up a bit, hit the reverse button again and it moves towards me. I'm not trusting the stressed sounds from the motor. Okay, it's proven it can move the trailer but there's room for improvement. Lots of room - this isn't going to work.

This thing is way too fast and it's pulling strength leaves something to be desired. I need to gear down the drive. Once again, pea brain starts shifting gears (literally this time) and I'm thinking I can build a reduction box and put it between the motor and the MDT's input. I have no idea what I'm getting into. Is it a shaft on a motor that fits into a gear on the MDT? Let's open it up and find out.

Turns out that this is just about perfect. It's a cush drive. The motor has a pin driven through the end of the output shaft and that turns a little plastic piece that fits over another pin that's on the input shaft of the MDT's transmission. I'm going to make a piece that fits between the two and drops the final drive ratio a bit.

Snowball didn't fail to live up to the new name. It threw in one little incident for good measure. When I pulled the motor I thought I had the battery disconnected. I’m used to one connection in RC stuff.
Unscrewed the power leg off of the motor and it flopped over to one of the battery lugs.
I hear "Pfft". Sniff, uh oh, I smell magic smoke.
Shit.
Lead slipped out of my hand again as I reached around to unplug the battery and POP, oh look, magic smoke!
Shit!
Look at the ic. That's where the magic smoke got out.

I've decided that I'll make a small reduction box. Back to Amazon to source more stuff. I do a bit of searching and come up with gears out of some 1/5th scale off road trucks. They fit the bill perfectly. With two sets of gears (20/45 & 20/50) I end up with a gear ratio of 5.625:1. That should be a lot slower and have a lot more torque. I also ordered shafts and bearings for the gears to spin on.

I sat down at the computer and started designing. Fortunately the gears are an off the shelf item and I was able to find CAD drawings of them along with all the specs. Perfecto! Click, click, click and I've got a drive train designed.

Off to the mill and I'm making parts.

I have a couple of good friends and fellow fabricators and we've had a group text among us for years. We're always sharing build crap, making fun of each other and such. You know, dude stuff. As I've built the Motor-Totor I've shared pictures of the build, like I'm doing here.

I get a text one afternoon "Snowball? Never heard of her. That's a terrible stage name..."
Huh? What in the world is Jesse talking about?
Then the next message pops up on my phone "That's what we should call her. Snowball. Snowball the robomover." Took me a couple of seconds and then I totally got where he was coming from. Yes, absolutely. The Motor-Totor quickly was rebranded Snowball as that's what it had become.

I got Snowball reassembled and set on the floor to see what if what I'd made worked. Man, it's noisy! I know one of the clearances inside the box is a bit tight. Nothing I can't fix. The nice thing is that it works. It's about the right speed and now that the ratio is lower the speed control is more precise.

I put the new transmission in and it was time to see if it'll move the trailer.

I didn't get any video because it's impossible to drive and film but Snowball is capable of trailer moving! It moved the trailer out of the garage and then back in. It's a beast to steer. The scrub radius (suspension stuff - how far the pivot point is from where the wheels touch) is way too large and it requires a lot of push on the bars to get anything to happen. I was afraid this might be an issue and Snowball stayed true to it's name. Also, the first try wasn't so good. She spun the intermediate shaft main gear.

Fortunately it's just a couple of bolts to pull the whole thing apart so tore it down, pulled the shafts out and put flats on both of them for the set screws in the gears to have something to dig into.

The steering was a bit of a brain scratcher. I wasn't sure what steering was going to be like but I found out and it's not acceptable. Almost think I need to spin the jack 180 and put the load closer to the trans-axle but I'm not sure it can hold the load.
I actually designed it that way at first.

With the flats in the transmission shafts cut I tried moving the trailer again. Yeah, it works, but it's a beast to steer and it's not happy pulling. The weight on the jack moves towards the caster wheels and the MDT starts spinning the wheels. This isn't going to work. It needs better traction, weight distribution and, well, to be a better design. Yes, Snowball is truly living up to the name.

I've been sharing this project on the Minibuggy.net Facebook page. I know quite a few there and they me. One pipes up "When will you be able to drive it with a RC car remote? Surely that's in the long-term plan, yes?"
Hmmm.... I've been called out. I thought the same early on. It would be cool and the units you can get from Park It 360 have remote controls - I think they're cabled.

So the issues at hand are steering and traction. Steering should be easy enough. If I can get the ball over the middle of the trans-axle I should be able to steer it without issue.
Traction... What am I doing to do about traction? Obviously four wheel drive would be the ticket. All four wheels driving should get rid of any slippage.
Yeah but how do you steer it now? Shift pea brain gears a bit and 'what if I make it 4x4 by adding another drive train and steer one of the trans-axles?'
Snowball is snowballing hard now.

Back on Amazon. I'm going to need another MDT, speed control, something to steer it with, an RC radio, gear sets and stuff to make another gearbox. Parts are ordered.

The new layout begins and Snowball is dubbed Snowball V4x4.

I wrestled with how to make this thing steer. There's going to be a lot of torque about the steering point, there's going to be quite a bit of weight on this point too. Both aspects require bearings. More searching and there's a large roller bearing and matching thrust bearing that are fairly inexpensive (there are some REALLY expensive options too. wow...). I'll make pivot plate that that attaches to the large plate (big LCD TV mount) I'm planning on using as the new body. I also find a large servo that just happens to be RC friendly. It's the biggest servo I've ever seen and puts out almost 30 lb-ft of torque. That should steer without issue.

The issue with the torque the steering MDT is going to put on the pivot area is going to be too much. I need to support the bottom of the trans-axle. Oh! I can integrate another thrust area onto the steering input. Kill two birds with one stone, or bearing if you will. I made a piece that holds a bearing and bolts to the bottom rib that runs along the trans-axle's cast body. The servo is going to need to move back a bit.

I've run out of 1" billet aluminum stock. It's what I've needed for the transmission halves and the steering stuff on Snowball. What I do have is some large chunks of billet from the The Mini-Raptor and a band saw (that actually cuts pretty darned straight). I proceeded to cut a piece off that was a tad thicker than one inch. I"ll machine it to size. Yes, I watch too many machine shop videos out of India (those guys are impressive with their abilities to make stuff out of nothing!)

Out comes the brace, servo mount and lower steering bearing

I made tie rods for the steering input since I had to move the servo back to ensure I had steering clearance.

I needed to address the height issue on the tie rods so a new bearing holder/steering arm was made with longer ears, getting rid of any bind that could happen without things being a bit more parallel.

Snowball laid on it's back, checking clearance, interference and such. The steering servo was a bit snug against the battery so I recut the pocket that it lives in.

Of course I couldn't just leave these pieces alone. They need a little pizazz so it was window and facing time. Now they look like proper machined billet parts.

Time to make gearbox number two. I actually decided to make two completely new transmission housings. The first one needed to be clocked a bit differently than the original mounting orientation (I pulled it in tighter to the MTD), I missed one mounting hole (it hit a bearing) and there was a small clearance issue with the first one too (noisy). Boxen numbers dos and tres came out sweet. They ran much more freely, fit better and tucked stuff up tighter.

Once again, I didn't have any one inch thick billet so it was band saw time again after each half was cut out of the top of a big ass chunk of aluminum.

I got the speed control for the second MTD mounted and wiredd and had room for one battery to be tucked up under the main frame plate.

When I flipped Snowball over to put the jack on it I realized that it was getting REALLY heavy. I'm having a hard time lifting it off the table to set it on the floor and vice versa. The jack fit perfectly, the ball centered over the non steering trans-axle, and space for the two boxes that hold the controls and RC stuff.

Earlier I made mention to the fact that the jack was not acting correctly. I started thinking about the wiring. There were three lines that went to the OEM battery. Power, Ground and Yellow. Yellow? What's that do? I don't have a battery in hand but there's something that tells me that it's involved. I order a battery on Amazon (since that's where Snowball's from) and start checking leads when it shows up. The yellow lead has 12v off of the battery. Interesting. Not sure why or how it's wired in either. I pulled the battery apart looking for something simple (because that's what I do with stuff I don't understand) and it's a pack of batteries and a control board. I can't chase this yellow lead back to anything in particular that makes sense to my non trained brain. Okay, easy enough. I have a battery and when I plug all three lines into it in their correct location what do ya know, the jack works. It works properly too, not short runs followed by the need to reset. Cool. I'd like to not have another battery for the system but since this one just plugs right into the jack, why not, what's it hurting? - my back from the added weight....

One thing that I can't find on Amazon is a radio control compatible double pole, double throw (DPDT) relay that can handle 24 volts and 10 amps. I need this to raise and lower the jack. It's simple on the jack, there's a toggle switch that's DPDT. Hmmm... all I need to do is actuate that switch. Time to get creative. I made a mount for the switch, stuck an RC airplane servo into the mount, made an arm that actuates the switch in either direction and leaves the switch in the middle, normally open position. Stupid simple and very effective. Plus I can dial in the throw on the servo so I don't over or under push the switch lever. It's activated by a switch on the front of the radio.

Next thing I needed was to be able to control the speed of Snowball. The speed control has two operations. A switch for forward and reverse and a potentiometer (a.k.a. a pot) for speed. Direction was easy. I found double relays that were plug and play RC ready. The speed control, on the other hand, was a bit different. Right off the bat I thought that I could use a servo to spin the pot for adjustment. My issue here was that servos only move about 90 degrees and I needed 270. More searching on Amazon and I come up with 180 degree servos. Cool, that'll work. I'm not using the bottom end of the speed controller. I'll just set them up so that full sweep is 100% of the pot's motion.

Now how am I supposed to make this work? More out of the box thinking (actually kinda in the box thinking as I look at the pix) was needed. If I put the shaft of the pot parallel to the output shaft of the servo that'll spin the pot. How do I couple the two pieces? I'd thought about cutting a tube out of aluminum and pressing them on but that was going to be a pain. I could machine a coupler but how to fit it on both pieces was a possibility but once again, a bit complicated. Then it hit me. They're both the same diameter, how about aligning them and then using some sort of tubing to couple them? I immediately thought of heat shrink but wasn't sure how I'd get it shrunk and still in place. As I'm mucking about looking for a tool I come across a piece of fuel tubing that's sitting on my bench. AHA!!! Out with a knife, two short pieces cut and my coupling was complete. I had to trim a bit off of the pot's input shaft. The really cool thing about it is that I can now clock the pots so that they both have the same output and both of the MTD would be in sync. Stupid simple, super effective. I put the servos on a y-harness so they both run off the same channel and mirror each other perfectly.

Speed control dilemma solved. I can dial it in right on the front of the radio as Snowball makes her trek to where ever we're headed. Once again, I have to mention that the control of Snowball with an RC transmitter is a bit tricky to set up. Instead of the throttle trigger controlling the speed and direction, it only controls direction. Pull the trigger and Snowball goes one way, push the trigger and she heads the other way. It's and on/off situation but being able to rotate a little knobbie on the transmitter and adjust the speed is easy enough. It's not like this thing rips across the room. It just crawls along.

I pick up Snowball, strain myself and set her on the floor. Time to see if it does what it's supposed to. It does but in Snowball fashion, it seems to want to cut out when I'm jerky with the controls. That's weird. It shuts down EVERYTHING. Not just the speed controllers going dead, everything quits. Hmmmm... Out with the good ol' Fluke multimeter and it turns out that the battery is shutting down. Odd. The BMS (Battery Management System - most LiPos have them to control charging, discharging, temp sensor and such. They're pretty smart) is shutting off. Why would it do that? Overload? Nah, I can't be spiking that much can I? Hmmm... I have the second battery, let's wire that in and see what happens. My phantom shut off disappears. I'll have to figure out where to mount battery number two. I also ordered a push button emergency kill switch that has a quarter turn reset. This is what I have on my mill and lathe. Slap the button and kill everything, give it a twist and it all comes back to life. No more having to unplug and plug in the batteries to cycle them and reset their BMSs either. Just a quick poke and turn and Snowball's back up and running.

I drove Snowball to the trailer, got it located (the speed control works really well - It just needs to crawl into location, not scoot along) under the tongue of the trailer, lifted the tongue and out comes the trailer. Snowball moves it easily and doesn't complain a bit. I reversed the direction, now with the load pushing away from the steering axle and Snowball immediately does this nice little wheelie. Uh-oh, dat's not gonna work! I was kind of afraid of this (had forshadowed it with the original design).

I need to have outriggers and the ball needs to be in the center of the unit. Easy enough. I still had the legs from the first frame. A quick hit with the Sawzall and then the welder and I had outboard legs attached to Snowball. I hung the second battery on the cross brace that was originally the jack mount. - and it was all I could do to get her up onto the bench to weld another twenty five pounds of crap on. Legs now installed I kinda poured her off of the work bench whilst grunting and swearing.

I drive her to the trailer. I line her up, making sure the outriggers miss the wooden block under the trailer jack and thud. The cross brace between the outriggers stops Snowball from fully getting under and letting me position the jack ball.

SHIT!
Snowball being Snowball!
Now I have to cut out the cross brace and figure out a spot for the battery. I drive her back to the bench and wrestle her up on it.

The cross brace is cut out, the battery is removed and set on top. That ought to work, right?

Back to the trailer and as I pull up the battery now hits the trailer tongue just under the receiver.
SHIT!
Snowball being Snowball again!

I raise the trailer with the tongue jack so I have clearance and drive her into position. Flick a switch on the radio, the jack raises and lifts the trailer tongue. I hit pull and Snowball drives right out, pulling the trailer along. Let's see what happens now when I push it back in...
YAY!
She squats under load but doesn't try to wheelie out. She just pushes the trailer back where it lives. Snowball works.

It's going to take a little bit of getting used to driving her. It's like normal driving a trailer - it goes opposite of what you're steering input is but it's strange to do it with a remote wheel in your hand and walking along with the trailer instead of doing everything via the mirrors on the truck.

Snowball has a couple of small tweaks and I have to make stickers - she needs some dressing. This has been a really fun project.

Stickers and a battery location mode are made and I'll officially say that Snowball is done.

The second battery ended up interfering with the trailer tongue so I moved it under the outrigger arms. I also got rid of the cross bracing on the outrigger so I had clearance for trailer the tongue jack. I also fully welded the outriggers onto Snowball's frame. I had just welded the sides of the tubes and there was a lot of flex when the trailer weight was set onto Snowball.

As I pulled Snowball off of my build table (she's a heavy beast!) I looked at the table and thought "Hmmmm.... I wonder if" so I fired up the radio and Snowball and sure enough she pushed my heavy ass build table across the shop floor into it's home. Mission accomplished.

I wonder what I'll get into next? Seems I have a The Mini-Raptor and some kaleidoscopes to finish