The Restoration of Overhaul 1: Wait, Why Did We Do It That Way Again?

Last November, I made a trip back up to Boston in order to retrieve some of the heavy things I didn’t bring down when I moved. One of these heavy things I explicitly wanted to get was the hulk of Overhaul 1, which had traveled with me out of MIT, through the Artisan’s Asylum, into the Old New Shop, finally to the New New Shop.

There it is, in the cruft corner of the New New Shop. When the wheel modules went into sadbot back in 2015, the shuffle drive pods were put back in as a visual completion piece. The motors were removed for future other bots – I believe those drive motors might have made it into the Season 2 Road Rash. While they were never used in the Season 1 competition, they were the last piece of the purposeful “Glue 3 designs together” approach we used for Overhaul 1, and the focus of a lot of effort during the build.

Beyond missing a few motors, the bot was exactly in the state it left the Nightmare and Witch Doctor rumble of Season 1.

This was the same trip that I acquired the Benchmaster, Master of Benches on the way up. I somehow managed to fill the back of Coronavan up without even trying. Thus is my life, apparently.

And thus, the conference of heavyweight robots is convened! The still unpainted Overhaul 3 is in the background. As I’ll expound on in its build reports coming some day soon, part of the design mantra was getting back to the roots of what I liked about Overhaul 1. I wanted Overhaul 3 to drive like Sadbot – as a result, I wanted it to drive like OH1. That meant going back to large, bouncy wheels over the old Biohazard inspired 6WD setup of Overhaul 2, and if you recall, 30Haul was made two years ago to explore the same.

My plan for Overhaul 1’s resto was to straighten the frame out so I can easily mount stuff to it again (but not repairing the battle damage!), and then putting some motors back in it. The old battery bay was to become an electronics-and-battery bay since it wouldn’t need enough energy to last a 3 minute match, just to drive around. The actuators for the lift and clamp were in fine enough shape and would just be taken apart for a quick inspection and rebuild if needed.

I began taking the thing apart and assessing what needed to be done. The right side of the frame was caved inwards from Nightmare brushing against it, for instance. This really prevented the shuffle pod on that side from being fully mounted (Its sidewall was also a little caved in, but not enough to matter apparently). Dings, dents, and nibble marks abounded on the rest of the bot.

The “pontoons” in the front warped when welding, so it was already bent anyway, but during the tournament it just ended up bending more. So I also had to figure out how to pull that straight.

I decided to force the frame apart hydraulically from the inside. Doing just enough Big Chuck’s Auto Body to have watched enough repair videos of car and truck body and frame pulls, I was out to try my sense of “understanding how the metal flows” when taking damage. Nightmare pushed the steel inwards, so pull it outwards again to compensate.

Initially, I tried with Mikuvan’s OEM tire jack. While it’s fine and enough for lifting one cheek to change a tire, against the AR400 steel plate and tube weldment, it was just… no.

And so I found myself running to Harbor Freight before closing time to get one of their big 20-ton bottle jacks. With this thing and a cleverly positioned Spool Bus Lifting Tool, I was easily able to force the frame rail back straight again by targeting the upper edge (where it got chewed first). The rest followed without much fuss.

While the tubing is crimped a little on that side now, it doesn’t matter, since all I need is the clearance. The damage is character.

I flipped the frame around to also push out the other side a little. An AR500 plate sits against the bottom of the jack and the recently corrected frame rail in order to boost its rigidity, such that I didn’t just balloon both sides of the frame outwards. I was plenty satisfied with how straightened the whole thing became, really. I didn’t expect it to work out this well!

For pulling the pontoons apart again, I had a creative method in mind. To execute this, I’d first need to weld a pull tab to the end of one of the pontoons. The idea being I’d fixture the pontoon center beam element to something relatively sturdy, and use a come-along or chain binder on…

…Yeah, what was anyone expecting? Dual vantruck metal forming.

I bolted the pontoon center member through one of the former 5th-wheel hitch mounting holes on Spool Bus, suspending it slightly off the bed by using spare Overhaul wedgelets as a spacer. This would allow the beam to deflect the other way as it was pulled. I wrapped the tow chain I keep in Vantruck around the pull tab and joined it up with itself, then attached the other end around the trailer hitch.

I then used a come-along to slowly pull on the length of chain. It looks and sounds far sketchier than it was in real life, but I made sure to use double layered eye/face protection and an few “Anti-kill-yourself” blankets over the chain and cables.

I mean, not that any of that stuff would do much against a potential flying 37 pound pointy steel thing, but it made me feel better about it!

It’s not totally straight (not that it ever was), but it’s better than before for sure. At least it’ll be straight enough to get the bolts started.

With all the frame bashing work I wanted to get done completed, I next moved on to the question of how to put motors back in it. Originally, we had just hung F30-400 Ampflow motors off the sides of the shuffle pods/wheel modules and used some tie rods to secure their back sides. This worked well enough for the time we had. I wanted to execute on an idea we bounced around but did not move on because of the extra complexity.

See, the motors I wanted to use were some XYD-13 24 volt scooter motors that I originally got as a what-if for Overhaul 3. I’m perennially of the opinion that these big ol’ scooter motors are underloved in the U.S. robot fighting scene (but rather popular overseas in the U.K. and Australia, as well as mainland Europe). Uppercut, the team of MIT ducklings from yester-season, also did very well using them for drive.

The plan was to center-mount them in the bot and use flexible couplings to connect them to the shuffle pods. Those seemingly random frame holes near the center of the bot’s wheelbase that were never populated? Well, that’s what they were originally for: Motor mounting.

This is what the arrangement will look like. The motor will drive a very short floating intermediate shaft made of spider couplings, in theory giving them a lot more isolation from the high vibration of the shuffle pods. Now I just needed a way to connect the motors together with themselves.

I decided on the fast, easy, yet effective way – use a Markforged print designed to give a little bit of rotational flex to hang the motors off the two long rails. The motors will be held together with 2 of these and standoffs as a central unit.

Here’s what the design looks like. The three holes are for the motors’s mounting flange, which will bolt through to standoffs.

And this is what it will look like in the design. The former Ampflow bolt pattern will have a small (also 3D printed Onyx) bearing block embedded in it with two flanged 1/2″ bearings to support the drive sprocket.

The design now finalized, after some adjustment of spacings here and there. The motor “pod” itself will be held in place by shaft collars, so I can make everything jiggly at first to do the side-to-side alignment before locking it in.

Fabrication of all this didn’t take too much time. So the next post installment in this “Charles really doesn’t want to start down the rabbit hole of recapping all of the Overhaul 3 content thus far” will be about getting the bot driving again!

Benchmaster, Master of Benches: a Robot Trap Shop Tale

You know, I told myself I’d take 2020 as a year to learn to relax, reflect, and stop building everything all the time because we’re all going to die soon anyway. And then I had to try and remember everything I did just since late September to write the last post. But there’s more, as in that post, I neglected all of the shop-building I’ve still been on a quest to do.

For one, I’ve been seeking a milling machine to accompany tinylathe (which does need its own writeup), but not needing one for business purposes, I wasn’t keen on buying a tinymill new. I kept an eye on Craigslist and Zuckerburg’s Emporium for good deals on small to medium sized mills – while I could have easily bought Bridgeport sized machines for days, that violated my rule for the time being of No Multi-Thousand Pound Objects That Can’t Drive Themselves.

My other constraint was no round-column mill-drills. I know they’d get the job “done”, but I can’t stand those things because of their propensity to rotate on the column and lose all your zeroes for you. So really I was just sitting on my ass waiting for “The One”, and was close to being able to get a few Grizzly mid-sized mills with square columns (and similar)… but damn, it turns out other people also want them, and they went quickly.

Luckily, fellow robot builder and machinery enthusiast Alex Horne made me an offer that I found very hard to refuse – on my way to Boston last November to obtain Overhaul 1 Among Other Things, I picked up this little guy from him.

Huh. Well that’s cute. It’s like a larval version of the classic American heavy manual mill pattern, like the first instar stage of a Cincinnati or Kearny-Trecker. I loved it.

The travel is about 12″ x 6″, which is pretty impressive. It’s in a similar size class as the Seig X2 type “tinymill” that’s sold everywhere, but built like a battleship. This was a difficult two-person lift, where as I alone can chuck a tinymill-sized machine onto the workbench back at MIT.

So I’m barely 2/3rds of the way to Boston and already have picked up several hundred pounds of junk. Well this trip is certainly going well! The mill came with this very heavy work table which itself was another hundred pounds or more of very dense and nicely finished Old Wood topping a frame made of 1/4″ thick steel angles.

We stopped by a local machinery dealer which I keep calling Hank Hill Machinery or Hillbilly Machinery to inspect their wares, and ended up finding a small treasure trove of full drill/mill/tap organizers. I spent even more money I didn’t intend to in order to swipe these – we made a “What if I took all of them” offer and split the goods afterwards.

So after I got back home and unloaded…. what on earth did I just buy. This is how I operate, as you know. Obtain first, figure out what it is you got after the fact. I’m literally the most advertisement-agnostic person on the planet. You can’t egg me on to buy something through viral targeted marketing, but you can set your product out so I trip over it and bring it home, then I’ll do research on how to buy more and subscribe to your services.

This adorable neotenic critter is a Benchmaster, made by a company called Duro that eventually just became “Benchmaster”. The product? Benchmaster. What does it do? Be the master of benches.

Picture shamelessly stolen from, so go visit them.

It was, as it seems, targeted at the hobbyist or a ‘second machine’ type situation. Sounds like a limited market, but they aren’t as rare as I thought they were, and an enthusiastic community exists around them where people have done comical swaps such as putting a Bridgeport M-Head on the damn thing.

If I haven’t beat this drum enough, I’d like to reiterate a point I made when I posted about crabmower: I bought an old, obscure device without knowing what it was, and someone had made an entire page on how they fixed up and modified it. Folks, this is why we’re here.

Alright, I now had to find a home for the Benchmaster so it can be the master of a bench. Ever since I built the benches, I’d already earmarked half of one of them next to tinylathe for the installtion of a mill. It had recently become occupied by random sanding/grinding tools and Overhaul parts, so there was a lot of cleanup and displacement to do.

Namely, all of my tooling (the stuff you need to USE a mill and lathe) had to be displaced. I therefore was forced on a hunt for new tool organization, which will come later. For now, it’ll just live in a pile on the floor like my soul.

I decided to disassemble the original heavy wooden bench to form a foundation for the mill. The 1″ of OSB my benchtops were made of felt just a bit too flexible for it to be a good anchor, so the plan was to secure the big wooden block to the bench, then bolt the mill through all of it.

The interesting thing about the Benchmaster is that the knee leadscrew pokes down from the mill by a fair amount. That’s why they always have to be on stands. I decided to drill a 3/4″ hole through everything as the leadscrew sphincter

#OSHACrane was used to line everything up and set the machine into position…

…upon which I lined it up with the marker lines I had drawn, then drilled through and bolted in-place.

And here it is, the menagerie of miniature machinery.

Alex threw in the 4″ milling vise, which we both agreed was way too large for this machine. It used up a significant amount of the Z travel just for itself, and this mill doesn’t have a quill (A bit annoying, and a good excuse to do a head swap later on), so its usefulness is severel curtailed. With the thing finally installed in place, I gave everything the ol’ lube n tune, taking the axes apart to adjust the slides and leadscrew nut tightness.

But damn is this thing rigid. Being made back when America was Great, Men were Men, and Steel was Free meant it’s exceptionally smooth (once I tuned the gibs in and cleaned & oiled everything) and I dragged this 1/2″ endmill at 1/2″ DOC through my sacrificial aluminum test piece at the highest spindle belt speed, and it barely flinched. This is a suicidal cut on a Seig X2 class mini-mill, and even if you did manage to do so by feeding slowly, the finish would have been chattery.

For now, until I want to get a 3 inch milling vise, I bestowed upon it my old toolmaker style vise that usually held motors under testing.

The other downside is at the moment it doesn’t have digital scales, so I’m back to using a lot of my “vernacular machining” skills learned years and years ago. My “edge finder” is really just putting a 1/2″ drill rod (itself really a cut-down, destroyed 1/2″ drill bit) into the collet and bumping off.

It fulfills my current “mill” needs quite well either way: Flat this shaft, key this, shave that down, bore this out. Anything substantially complex right now I have enough contacts and favors to call in so I can have a part made. I’ll be planning to add digital scales soon, and I’d like to eventually see if I can get it a quill via head swap or severe head modification.