Attitude Adjuster (Beetleweight)

Inspired by going to the filming of S1 and S3 of the Robot Wars reboot, my friend and I have decided to each build a beetleweight robot and are aiming to complete them in time for the Euro championships.

I want something that's more interesting than a box on wheels and I've always liked hammer/axe bots like Terrorhurtz, Beta and Mega Melvin so I've decided to design and build one of those. I know they're not super effective at the lower weight classes, but that suits me as I want something that isn't a scary spinner for my first build.

After reading all of the build threads in here (and being particularly inspired by the detailed build diary for This Is Not A Drill, amongst others), over the last few weeks and months I've been gathering bits and learning to CAD on Fusion 360. I used to "build" vapour bots in CAD back in the days of Series 5-7, so it is all coming back. I have also joined a local hackerspace, so I have access to a workspace with suitable tools for making a beetleweight.

This is the design I have so far. It's still WIP as I think there is some wasted space, and it is pretty close to the weight limit so I'll need to lighten it somehow.

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The bulkheads are 10mm HDPE, the wheelguards and rear are 5mm HDPE, the top and bottom are 2mm polycarb and the wedge is 1.2mm Grade 5 titanium.

It's driven by 2 of the standard 1000rpm motors, with a 3S 1000mAh Hobbyking lipo and a Sabertooth 2x12A ESC.

The axe is 10mm square aluminium 6061 bar, with a 2mm Grade 5 titanium axe head. It's currently powered by another 1000rpm motor geared down by a toothed belt at ~2.5:1. I think that probably needs to be changed though, it's too fast for an axe and I don't think it will have enough torque to self right. I was thinking about either a 37mm 500rpm gearmotor I have lying around, or possibly even going brushless for the weight/size reduction. The only doubts I have about brushless are that I'm not sure what motor to use or whether that's too ambitious for a first build?

Ebay has been my friend for this, I picked up a second hand DX6i, all the random bits of metal, a Chinese car ESC for messing around with and all the screws.

I've made a test bot made of some eBay motor mounts and a bit of polycarb that I can go chasing the cat with to prove that I can actually build a robot and wire it.

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I've also built a test axe platform using an old chopping board I had lying around. The cat REALLY doesn't like that.

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And finally a bit of CAD (cardboard aided design) to check that everything is a sensible scale.

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The most important part is thinking of a good name, which I am rubbish at. I decided to take inspiration from the ships of Iain Banks' Culture series of books, and the one that jumped out at me was "Attitude Adjuster", so I went for that.

As soon as I finish the CAD design to a "good enough" standard then I'll be able to start building! Any comments/feedback on my design so far? In particular I'm interested in feedback on the weapon, on electronics/brushless motors, and whether I'm doing anything stupid.

Awesome work, will be nice to have more weapons like axes in the beetle class, i've always wanted to make one myself but ended up going with spinners

Thanks man! Ask Aaron seems to think that axes are ineffective in the insect weight classes, but we'll see how it goes :D

Anything can be effective with enough force and sharpness ;) I am looking forwards to seeing this at the European Championships.

Sounds really good Scott. The internals sound similar to my Evil K'Weevil.

It's been a while since my last update, life got in the way which meant I didn't have much time for robot fun, beyond terrorising the cat with my test platform.

I've been refining my design to optimise it for weight, until I realised that in my spreadsheet of component weights I had the fingertech wheel hubs as 70g each instead of 7g! So with that sorted, I decided to start making bits of plastic smaller.

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I have a sheet of 10mm HDPE and a sheet of 5mm. So far I've made the sides, the front and the rear bulkheads. I was using the table saw and chop saw in the hackerspace for the first time, so I used an old plywood cupboard door that I had lying around to practice on.

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Some of my images have uploaded sideways :/ With plywood bot done, I moved onto chopping up the HDPE. I made it slightly too tall by a couple of millimetres, so I will look into taking that off using a plane next time I'm in the hackerspace.

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I'm not totally sure how to connect the rear to the sides. I'll probably use long wood screws to connect the front to the sides, but for the rear I want to also attach the wheelguards using the same bolt. I used a spare bit of HDPE to test out my idea for using threaded inserts to make them removable, however I'm not sure if there's enough on each side for them to bite into, what do you guys reckon? I'm planning to make some threaded bar out of aluminium for the wedge and the top and bottom plates, possibly with an o-ring for some ghetto shock mounting.

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Over the last few weeks I've been learning how to machine aluminium using the small metal milling machine at the hackerspace. You can see below my attempt at making a bit of 2mm aluminium into a square (ignore the bit where I broke a drill bit...). It's satisfying when it turns out more or less how it was designed in CAD!

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Next job is to get the edges of the parts brought and then to get some holes drilled so I can mount the motors in the side bulkheads, hopefully I will get to that in the next week or two.

Small update - I needed to shave a few mm off my pieces of HDPE and remove the saw marks, so I used a hand plane, which worked pretty well. I now have some pieces of HDPE that are roughly the same height and the right length. Next step is to make a template for the holes I need to make for mounting and motors, which I'll laser cut in some MDF.

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Before I can start on weapon construction I need to finalise the design. I've already bitten the bullet and finalised the dimensions of the robot as a whole (LxW 17.5x20cm), but I'm still not 100% on the battery placement, which affects the construction of the weapon bulkheads and the distance between them. I had them right next to the weapon motor in the initial CAD, but I think that it is too close to the weapon wires. I can't make the body wider as it is already too wide, and my piece of Grade 5 titanium is 20.2cm wide.

I'm thinking of making a battery box to be mounted to the weapon bulkheads, sideways so it doesn't interfere with the weapon belt. Is the design/idea in the second image too complex or vulnerable? The plan would be for it to be protected by two layers of 3mm polycarb, and for it to be easily removable for serviceability.

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Looks OK to me, if a bit tight to the motor. Worth experimenting with the orientation of the battery so it is vertically mounted in the robot rather than horizontally? Looks like it is coming on well though ;)

Thanks for the words of encouragement! Good idea, when I have a rolling chassis up and running I'll check out having it vertically before making a final decision, my hesitation was that it would be tight to the top of the chassis, as the chassis is 35mm tall and the battery is 33mm.

Weapons that go through the top of robots in the BW category are comparatively rare compared to the side. However, I wouldn't be comfortable with that much clearance either (though says me, my Beetleweight's batteries are pressed up against the rear panel :S).

I'll see - it could be that I just double up the armour around the battery. My thinking was that there are a lot of scary drum spinners that would love to chomp through the top if it was upside down!

I have flashes of Bourbon and Ion in my mind, yeah, they might make it in.

Made quite a bit of progress since the last update, so I have a lot to post here (evidenced by the fact I maxed out the images that I can attach :D). Apologies that all the images are sideways :/.

I have access to a laser cutter that can cut perspex, so I made a drilling template for the side bulkheads, based on my CAD. I drilled out the holes for the side bulkheads and then used a Forstner bit to drill out the holes for the drive motors, making a satisfying shaving as they did so.

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I then added the threaded inserts to the back of the side bulkheads and drilled holes in the rear bulkhead using a similar method. However, the holes didn't quite line up so I had to use a Dremel and needle file combo to make it fit. Then I could fit the drive motors to the side bulkheads and attach the rear to the sides!

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Then I was ready to attach the front to the sides. I decided to use the "really long wood screws" approach, so drilled out pilot holes and then attached them.

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...And then I realised that the front was upside down. Oops. Anyway, I put the chassis on the right way up and attached the Fingertech foam wheels and had a rolling chassis to decorate the spare room.

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I decided to make use of the laser cutter to make a perspex prototype of the weapon bulkheads, again based on my CAD, so that I could see how the components all fit together. If only I could laser cut the HDPE and polycarb for the rest of the robot! I only had access to 3mm perspex so I had to make 3 layers per side. I jammed all the components inside the robot after putting together the perspex weapon bulkheads and realised that it's going to be a tight squeeze with the wiring...

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With the robot looking vaguely robot shaped, I was about to go on holiday for 3 weeks. However, before I left I decided to cut the polycarb baseplate using a mitre saw. This was a mistake, as the sheet of polycarb shattered, and bits went flying everywhere. Safety goggles are important, people. I learnt that I should've used a jigsaw to do this. Oops. This was the result.

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When I got back I focussed my attention on the baseplate. I again cut out a prototype in perspex, and duct taped it to the bottom of the robot. Again, if only I could do the rest of it in the laser cutter! I used that to cut out the real baseplate out of polycarb, using a jigsaw this time. I discovered I can't cut straight at all, but I've made it work for this. I decided to attach the baseplate using brackets similar to Fingertech's Nutstrip (https://www.fingertechrobotics.com/p...?prod=nutstrip). Sadly, this isn't available in metric, so I made my own. I had two bits of 6082T6 aluminium bar stock, which I drilled M4 holes at 12mm intervals. The first one seemed straight enough, but the second one went a bit wonky... I'll probably scrap that one and do it again.

I finally made enough to be able to cut it into strips small enough for me to attach the baseplate. I went for 6 bolts, 3 at the front and 3 at the back. While the weather outside was "taps aff", I was doing some tapping of my own. I eventually tapped enough brackets to be able to attach the baseplate. I now need to update my CAD to take these into account.

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Today I worked on the wiring. I made a wiring loom for the main wire, which includes a removable link. I stole the method of attaching the ESCs to the main battery from somewhere, but unfortunately I can't remember where. It involves crimping ring connectors and attaching them together using an M3 bolt and nut. I then put everything together and once again had something that I can scare the cat with.

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As I saw earlier, there isn't a lot of room to play with in there when you add in the wires, so I'm a little worried about that. One possible option if space is tight is to swap out the Sabertooth for Vex 29s or Botbitz 10a ESCs. A lot of builders seem to be wary of the Sabertooth, and it's a little bit big and heavy. For now though, I'm glad to have something robot shaped. Tomorrow is the last chance I'll have to do something uninterrupted, before I have to go back to work. I'm planning to tidy up the wiring and possibly try and do the weapon bulkheads. I need to finalise the design for that piece, or I might just start building and see what I end up with...

One other thing, I have a piece of 1.2mm Grade 5 titanium for a wedge, how am I best to cut and drill this? I was thinking about using the abrasion cutting wheel of my Dremel, and using a 4mm cobalt drill bit, is that along the right lines?

Drilling with a Cobalt Tool is a good idea, just use low cutting speed and cool the drill.
You can also use a normal sawblade for metal and cut it with a hacksaw.

if using conbolt drills, go slow and use lots of coolant. i was able to drill through 3.2mm Hardox with some cobolt drill bits from Toolstation - about £3-5 each 5mm-7 about

Lots of progress since the last update. I've been accepted for the Euros with Attitude Adjuster, so that gives a good deadline to work towards.

I cut some weapon bulkheads, using the tried and tested technique of the table saw and the mitre saw. I used a 20mm forstner bit to cut out some holes, and measure the distances this time instead of laser cutting a template.

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The biggest game changer is learning how to use the 3d printer at the hacker space. It only uses PLA, but that should be enough for what I want to use it for. I started with a battery holder for the 3S lipo.

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Then I made a holder for the electronics at the back of the robot, so they don't get in the way of the weapon. I also made a couple of armour mounts. I put in some threaded brass inserts using a soldering iron. I also put some brass inserts in the chassis to hold the weapon bulkheads on, and to hold the top armour.

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Today I finally got around to finalising the design for the axe and cutting some titanium! I used my Dremel to cut it initially, then finished with a hacksaw, and drilled with a cobalt bit. Going slow with lots of lubricant made it super easy, and there were some fun sparks. I now have an axe head.

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I weighed the robot chassis for the first time, the bolts and brackets must weigh more than I thought!

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Also considering going brushless. I tried the axe for the first time with a 300rpm gearmotor and was disappointed with the power. It was slow and couldn't self-right. I picked up some brushless DYS BE1806 motors that have already been converted with 1000rpm gearboxes, and I'm considering transplanting the 300rpm gearbox onto one of them. I also have a 500rpm motor as a last resort. I also picked up some cheap Afro ESCs on ebay and flashed them with SimonK.

When testing my flashing, disaster struck! I accidentally plugged an Afro in the wrong way, and promptly blew it up. The battery also doesn't seem too healthy (feels a bit swollen :/) so I'm planning to not use it again in case I burn my house down, and have ordered a replacement. I will now not do anything with a lipo unless I use the wiring harness that has a fuse and removable link.

Finally, been doing a lot of soldering. Added connections to all my ESCs so that I can't plug them in backwards. I also need to make my wiring loom A LOT smaller. There is not a lot of room for the wiring in there. I have about a month until the Euros and not much free time in September, so I will have to try and make time when I can!

Small update for today. Spent a few hours making the axe, so now I have a weapon. It has an aluminium shaft, aluminium supports for the axe head, 2mm titanium axe head and a 3d printed spacer between the head and the supports. I saw in the FRA rules there's a section requiring a tether, does anyone know if that's something I will need to implement in my beetleweight? If so, what should be tethered, just the axe shaft? What do other people use for tethers?

Also, it is still satisfying when the robot looks like the renders :)

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I don't recall tethers being a thing at the BW level, best check with the event organisers. Certainly at the UWE Beetle Brawl in February, I can't remember seeing any but then again, I don't recall there being that many axebots around.

If I remember rightly, tethers are more for Grade 3 arenas and lower (aka non-spinner) so the tether is to prevent the axe head, or part of the shaft, flying away if it breaks off and potentially breaching any wall or netting. As far as I know it's not required in spinner-capable arenas as a flying axe head will have much less danger potential than the amount of shrapnel that gets pinged about. To my knowledge there aren't any active/regular beetle arenas that aren't suitable for spinners, so you should be fine. If in doubt, contact the organiser for any events you're planning to attend.

Thanks Michael and Jamie, looks like the best idea would be to double check with the event organiser.

Another quick update - finally put the axe together. I swapped out the 300rpm brushed motor for a 500rpm brushed motor and was pleased with the torque, as it can self-right, but not so much with the speed. I'm going to experiment with putting the gearbox from the 300rpm motor onto one of my DYS BE1806 brushless motors to see how that works when geared down ~3:1 by the belt. I should also make a tensioner, as the belt is a little bit slack, though that could be good for protecting the motor.

I put the robot together but was having issues with the snap ring staying on the Fingertech hub, I think I might've bent them. I've ordered some replacement 7/16" snap rings that will be arriving later this week. The axe hub and pulley also work themselves lose, so I will put some blue threadlocker on them when that too arrives later this week.

I did a quick weigh, and it comes in at ~1250g. That means I have ~250g for the wedge + mounts, wheelguards, foam wheels, drive ESCs, various nuts and bolts, and final weapon motor mount.

Still quite a bit on my to-do list:
* Cutting the titanium wedge
* Making the mounts
* Making wheelguards
* Cutting the top covers
* Adding a fuse and power LED (I have both of these, they just need fitted)
* Making a cradle
* Making a weapon locking bar
* Putting the wheels on and making it move
* Loctiting all the bolts
* (If I have time) Making the hammer more potent
* (If I have time) Making spares, e.g. top covers, wedge, hammer, etc
* Anything else I've missed! (Anybody notice anything?)

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Looks good. I might suggest some top padding/extra armour over the battery area as that top armour looks fairly thin to me.

If you need to get some weight reduction in, I'd possibly look at the axe arm with a few smallish holes in it.

Not a bad idea, it's 3mm polycarb but with some scary looking saws around then I might see if I can double the thickness around there, or put a little but of 1mm titanium under the polycarb to protect the battery. I have access to a manual mill, so if necessary I could mill some chunks out of the axe arm, it's 1/2" 6082 aluminium for sturdiness.

Small update on progress from this weekend. I 3d printed a new weapon motor mount and combined ESC container and rear armour mount in some snazzy red PLA. I drilled out the top armour so now I can mount it. I also spent a few hours on Friday sculpting the wheelguards out of 5mm HDPE using a vice and a heatgun. Weight-wise, it's sitting at 1360g without the wedge, wedge mounts/bolts, drive ESCs and one wheel. I've also used a couple of 3d printed armour mounts, hoping they hold up.

The main bit of construction left is the wedge, and drilling out the mounts for that. I'm aware I've also put the weapon motor in harm's way, so might add a little bit of polycarb to protect it. I need to also add the fuse and the power LED, and the weapon locking bar/sharp edge covers. Also wondering what spare parts I should bring, I was thinking about spare wedge if I have time and maybe a spare top panel, as well as a spare ESC, motors and wheel hubs?

I got the axe running at the hackerspace, so we had fun making little dents in bits of wood. I don't think it will cause that much damage, but it can self-right the robot using the 500rpm motor. I also tried running the wheels using the brushless gearmotors I have and the power and torque of the 1000rpm gearbox immediately caused one of the wheel hubs to loosen. Oops. I have purchased some threadlocker, and will transplant some 500rpm gearboxes that I have onto the brushless motors to make them a bit more controllable.

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After an hour and a half and 3 dremel cut off wheels I have two wedges. The sheet of titanium I have was the right size to make two wedges out of if I cut it lengthwise. Luckily I laser cut a template wedge out of acrylic, I discovered that I hadn’t updated the holes on the wedge to reflect the latest size of the robot and distance between the bulkheads. Need to drill out a bunch of holes, but shouldn’t be too much work. I need to make 4 aluminium brackets for the wedge, as the ones I made before are wonky. If I ran out of time and 3D printed them out if PLA would they hold up in combat? How does PLA generally hold up at a beetleweight scale?
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Drilled the holes in the wedge. Unfortunately the 3d printed mounts didn't work out. I printed them with 100% infill which was a mistake, as when I melted the brass inserts into the mounts the plastic had nowhere to expand to and the mounts ended up warping. I'll go back to my original plan of aluminium. This meant the holes didn't line up. I feel I may have to make them slightly bigger anyway, we'll see.

I took the protective coating off the polycarb top panels for the first time, it looks weird without the translucent white! I have some vinyl wrap I can put on if I have time, but that is literally the lowest priority job at the moment. Due to the constant re-designing of the internals there is now quite a bit of wasted space inside, which is disappointing.

More pressing is the weight - without the drive ESCs, wedge bolts, removable link, fuse, power LED and one drive wheel it weighs in at 1482g. Hopefully I'll save some weight by going back to aluminium wedge mounts, but it's still going to be a little bit over. I think I completely underestimated the weight of the nuts and bolts and wiring. Oops. Planning my weight saving holes already!

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Looks very good! I wouldn't worry so much about the internals at the moment and focus on the weight problem. Do you know if it is the axe arm and head that is the main weight culprit here? It could do with a few weight saving holes in it by the looks of it.

Thanks for the suggestion Michael, will look at that tonight. The axe shaft is down as 80g in my spreadsheet so I think some holes could help. The supports holding the axe head to the shaft are also bigger than I intended. My main issue is probably nuts and bolts and wires - I don’t think I took account of them in my design and they are possibly contributing to the mystery extra ~130g.

In other news I made a carrying cradle out of some wood I found lying around, so that will keep the wheels off the ground when it is in the pit. I mounted the wedge, using my dremel with a carbide cutting bit to “adjust” some of the holes I put in the wrong place. I also replaced the 500rpm brushed motor with one of the brushless motors with a 300rpm gearbox on it, and it was scary! However it shook itself apart after a few “good hits” on a block of wood, so more work required. It also jumps a bit.

Finally, any recommendations for sharpening my wedge? I have access to a bench grinder, will that do the job? I did the axe using a sharpening stone, but it took ages and I think it might be too small.

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Ah, good point about the cradle. I have some old wood from a AW arena build that I can use for that. Yeah, in building my Middleweight, I figured that the 230+ bolts in it would contribute to the weight. It turned out to be more than I expected as well. Once there is a bit less weight swinging, the jumping might be alleviated.

Won't the Dremel do for for sharpening the wedge (remember, you need to have a cover for sharps protection)? I'll probably end up doing that with Shu! when I tidy up the new arm.

Good idea, and yeah, I was planning to use duct tape and cardboard for the sharp edge protection! What dremel bit do you use for sharpening the arm on Shu!?

For the small things, I tend to use the aluminium oxide grinding rotary bit (the pink stone), which is just coarse enough for steel (which I've used on The Honey Badger). For Titanium, I'd possibly experiment with the same bit, using a coarser bit of it is required. I've not worked with Titanium but I understand the sparks can be hazardous to health so the usual precaution of a face mask and eye protection.

My previous update was a few days before the Euros. In that time I had to put both wheels on, finish the weapon, and generally prepare for the competition. I had never driven it, so I tried it as soon as the wheels were on. Unfortunately I found the wheels had virtually no grip, and the pinion in the brushless motor almost immediately came loose. I epoxied the pinion back on and crossed my fingers. A couple of late nights to make some last minute changes, and an afternoon of cutting bits of polycarbonate to make spares, and I was ready to make the drive to Marlow.

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The drive took 7 hours, but I was as ready for the competition as I would ever be. I was nervous, but my main goal was to not embarrass myself.

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And then we were at the competition! I got there early and set up in the room next to a computer. I passed safety without trouble. I'd drilled a hole in the weapon bulkhead for a locking bar, I'd made sharp edge protection out of cardboard and duct tape, and I'd verified the failsafe behaviour. I then went and had a look around everyone's robots. I was really wowed by how friendly, welcoming and helpful everyone was. It was especially great seeing Michael (Ocracoke), and thanking him in person for all the help and advice on this forum.

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The draw came out and as a coincidence my first ever battle was against Michael with Shu!. I powered up for the first time, shaking with nerves. I tried the weapon and it worked, but then disaster struck and the axe wouldn't retract. Michael offered to let me fix it, but I knew it would require taking the weapon apart to fix so I accepted it. I'm happy to say that I won, even without the weapon. The robot was very fast and powerful but uncontrollable and the wedge was too low so it kept catching on the uneven floor. After a near-miss, almost driving into the pit, it appeared that I had damaged Shu!'s wheel and Michael tapped out. So I'd won my first battle! But I had work to do to get battle-ready for the next fight.

After I got back to the pits I discovered that the axe wasn't working because I hadn't threadlocked the Fingertech pulley and so it was loose. After taking it apart to threadlock it, I then turned my attention to the drive. The pinion gear had come loose again, so the motor was turning but the wheel wasn't. I replaced the motor with my spare, and put everything back together. On the radio I had set the limit to about 70% on the drive already, but Michael gave me some further tips on setting up expo on my DX6i.

I discovered second round battle was against Inertia 2 and Drizzle, made by the team that made Tauron and Monsoon. Being a keen Battlebots fan, I was both nervous and excited to go against such a scary looking machine. What resulted was a great fight, that could've gone better for me but was a great experience.

https://www.youtube.com/watch?v=k8zoUjCnJdI

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Overall, I was really please with how the robot performed in the fight. I got a few "GOOD HITS" with the axe, including stopping the spinner of I2, and the robot was more controllable with the exponential rate set up on the radio so I got a few good attacks. The battle ended for me when Drizzle hit the side and shattered my polycarb top panel, leaving the receiver hanging out. I tapped out after that, because I didn't want to risk any more expensive damage.

When I got it back to the pits I assessed the damage. The drive pinion came loose again in the motor that I repaired the day before, so I lost drive in one side again. looks like Drizzle hit the wrong place on the side and cracked the polycarb, which caused it to go through the bolt. The 3d printed bracket also broke, and the panel shattered at the back, again at the bolt hole. I think a washer would have helped on the bolts. I was pleased by how the 5mm HDPE wheel guard tanked the hits, and how the 10mm bulkhead also held up, though Drizzle also got one of the wood screws that attach the sides to the front and bent the head of the screw.

That was it for the day for me. I considered using the backup brushed motors I had brought with me and fighting in some whiteboard battles, I didn't in the end. I also didn't fancy the rumble at the end, since I want to iterate on Attitude Adjuster for next year. I have some ideas around replacing the motor shafts with shafts from the brushed donor motors to fix the loose pinions, increasing the power of the hammer by using a bigger motor, and finally by making the footprint of the robot smaller, as there was a lot of wasted space when I moved to brushless.

I've taken a break from the robot over the last few weeks to focus on other things, so it is still in bits after the Euros. I'm going to give a small talk at work because everyone has been asking about it, and I've been showing everyone the video. I plan to put it back together with the more reliable but heavy brushed 1000rpm motors for demo purposes to give people at work a shot of driving.

It was a great experience, I met a lot of great people and I achieved my aim of not embarrassing myself. Will see everyone next year! Hopefully I might even make it to another competition before the Euros.

Great to see you as well, glad I was able to help out with your robot during the Euro championship! Hopefully we'll have another match soon with a rebuilt Shu!.

So cool to meet you (and fight you) at UWE, Scott! Glad to know my ramblings can be inspiring ;)

Any upgrades planned for the future?

Quote:

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Originally Posted by Zenith

So cool to meet you (and fight you) at UWE, Scott! Glad to know my ramblings can be inspiring ;)

Any upgrades planned for the future?

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Likewise Greg! Your diary was one of my most read bookmarks. The interlocking method definitely adds strength and rigidity.

At UWE bot brawl I was happy with some parts of the bot and less happy with others. Due to time constraints before the event I focused on fixing the things that went wrong at the Euros - the drive and the top armour mounting.

I reverted back to the standard 25mm brushed gearmotors to replace the brushless drive, as I had problems in both fights with pinions coming off at the euros and leaving the drive incapacitated one one side, and I increased the diameter of the Fingertech tyres to give a bit more ground clearance, which prevented the bot from bottoming out on the arena. I also rounded off the corners of the wedge to make it less likely to catch on the floor, which was also helped by work done on the arena before the event.

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I also used washers on the screws in the polycarb of the top panel, to repeat the incident where Drizzle ripped the top panel off and pulled the polycarb through the screw. I also replaced the 3d printed mount that shattered with a bit of homemade aluminium nutstrip. I extended the wheelguard to protect the screws that attach the sides to the front, as they were another victim of Drizzle. That paid off, as that area suffered a hit by Wee that would've done hit the same screw that Drizzle hit :)

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Areas for improvement are the weapon, the front armour and the drive. The axe stopped working in all fights :( This caused it to lose to Sir Lance-A-Frog when I was unable to self-right, and to Crabsolutely Clawful when I lost the judge's decision

It's currently using a DYS brushless motor attached to a 25mm gearbox, and the axe strips the gears. Probably not helped by me turning the power up to 100% instead of 80% on the transmitter, and by using a drive ESC which has braking enabled. It's a design flaw as I also stripped my spare.

I'm going to work on both increasing the power of the weapon and improving the reliability. I have a Propdrive outrunner which I'm looking at gearing options for, and a drill motor on order. I'll try and do some sort of v1.5 of the current chassis, but I also need to lose a lot of weight from it. The chassis is designed around a long battery and Sabertooth, so there's scope to make it a bit smaller.

The front armour did its job by taking a hit from a dying Rev 3 in the gladiator, but it's only 1.2mm grade 5, and after I saw what some of the spinners did to the 2mm of others' bots, I feel it needs beefed up. The bot as it is is pretty wide, so I could probably cut it down or optimise it.

The drive was reliable this time, as it was mobile at the end of all fights unlike last time, however there was no pushing power. The wheels are narrow Fingertech hubs, and would spin as soon as I got under an opponent. Mark Leigh from K2 gave me a tip of using liquid latex on the wheels to give a little more grip. The ideal would be to go 4wd by printing some hubs and casting my own tyres like Saw Loser and Flick, but I'll see how the liquid latex goes first.

Speaking of Flick, Tom kindly ran a giveaway on his build video for Flick, and I won the draw, so it is currently sitting in my spare room waiting for some attention! My plans are to get it running by fixing the side of the drive that isn't working, and putting some form of titanium on the front so that it can run in a non-spinner whiteboard.

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In terms of the actual event - it started badly when I didn't read the details properly and went to the wrong students' union in Bristol, going to Bristol University instead of UWE, doh! Luckily for once in my life I was early, so I had enough time to get to UWE. I was sharing a table with Tweedy, who I knew from the famous Battlebots fight with IceWave. He was really nice, and helped me when I had radio interference issues just after safety.

My first fight was against Sir Lance-A-Frog and Koffin. Unfortunately Koffin were having issues with being front-heavy so were unable to drive properly, so Lance-A-Frog and I battled between ourselves. I got a few good hits on Lance-A-Frog with the axe, and we used Koffin's spinner as an arena hazard. The axe then stopped working, so when Lance-A-Frog outdrove me and flipped Attitude Adjuster over against the wall I was unable to self right. However, it was a very good fight and Nick is a great guy and driver.

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The redemption battle was against Crabsolutely Clawful, a bot with giant crab claws. The fight started well for me, with a few bonks being delivered to the top of Crab, but due to the awkward shape of Crab and Joe's superior driving, I was unable to get around to the side of it. Then I saw as the hammer started to slowly die as it stripped the gears in the gearbox. The fight went to the judges, who ruled in favour of Crabsolutely Clawful as it controlled the fight and my axe died. However, I did manage to pop off one of the googly eyes, so I count that as a small victory.

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I was then out of the main competition, but Joe helped me by setting up a whiteboard tag team battle with Attitude Adjuster and Anxt vs WeeWoo and Rest in Pieces, two axebots vs two clusterbots! Greg and Cosmin used this opportunity to test out the new WeeWoo, which looked very potent. I was really looking forward to teaming up with Anxt, it was one of my favourites from Bugglebots and I picked Ralf's brain about almost every aspect of it. As expected, the match was chaotic and fun, with robots everywhere! Even though I replaced the axe motor with a spare, it stopped working again quickly. Wee got a couple of good hits in, which went through the wheelguard and took a chunk out of the baseplate, but no major damage, and then both Anxt and Attitude Adjuster were dispatched in the pit.

Finally there was the Gladiator battle, where every robot that was still running was put in the arena for a total of about 22! I knew the axe was unreliable, so my strategy was to stay out of the way of the scary spinners, use other robots as a shield and to not use the axe. I achieved the first two but couldn't resist trying the axe, which failed after a single hit and was left sticking out of the front of the bot. It took a hit from a drum spinner, I think, which reset it so I could use the wedge, but also took a chunk out of the 2mm titanium axe head. The other parts of my strategy worked well, and I was in the final three against Rev 3 and WideBoi. However, the lack of traction meant I was unable to push WideBoi into the bit, and then I drove in myself! Wideboi was the winner, and Shakey got a prize on his birthday!

So to sum up - the drive was in a place where I was happy with it, and now I need to sort out traction and making the axe more scary and reliable!

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That was a great write up Scott, good luck with the next stage.

The gladiator fight at UWE looked like absolute bedlam...

Thanks Sam! It was carnage but great fun, the pit had to be emptied several times :D