Hey you fun zesty individuals. I’m planning to dump out all my 150g laundry here as and when I build things. I tend to do ants on a whim so they will fit no concrete vision and progress will be pretty much either feast or famine.
Recently I went along for an afternoon of robotic violence at the Cider box where I plucked a plastic FBS out of my arse and into reality in a couple frantic days. It had a fairly sedate set of components that were all just hanging around in my parts box. It was fantastically terrible and terribly fantastic at the same time.
To be Bants legal it sported a plastic shell and impactors which held up pretty well (he says knowing full well it split along its layer lines in every single fight)
I put a lot of this down to a wibble in the print and being rushed out in the absolute cheapest and nastiest PLA known to humankind. I think the idea has legs however and since Bants are dropping from 175g to 150g it makes sense to rip up this design and start again. It has a lot of good ideas just poorly executed. I am going to shrink it all down, make it cube legal and gear up for full combat.
The drive system was pretty neat on the V1 but I had to change things up a little bit for the new version. I’m planning on O ring tracks which lets me direct drive the pulleys.
First drafts are printed (obviously) and it’s looking pretty promising. So far I am planning nylon for the shell with some kind of metalic impacting surface in the form of a ring disc.
Really impressed with this design! About the simplest I’ve ever seen an FBS, but it sounds like it can give quite a punch if the prints are splitting like that! Am excited to see what the V2 with better materials looks like. Am reminded of Wajoo the more I look at it, which is only a good thing (I think Wajoo was also gonna be 150g originally if I remember?).
For those not in the know, I had a semi successful 2wd beater robot at the last AWS I attended. It worked way better than I expected and came away with the most succulent and illusive of treasures - a positive W/L ratio.
I wished to improve it by toughening up the weapon and the chassis. The biggest change was changing out to a more traditional drum style of weapon with countersunk bolts for teeth and adding in a massive dead shaft in the form of a M4 shoulderbolt. This ties the front bulkheads of the robot together and should increase strength massively (the old frame cracked with impacts) The rest of the chassis remains mostly unchanged aside from adding in some geometry for heat press inserts and trying to remove a few tiny atoms of weight here and there.
Satisfied enough, I bought my ticket and took the ride. Within 2 weeks I had some pleasing clickly clacky blocks of 6061 to play with and I quickly installed a magnet ring and the two 5mm ball bearings. With the addition of a single shim washer it spins beautifully.
I kept the stator connected to the ‘base’ of the motor, only modifying it to knock out the tiny bearings and ream out the bore to 5mm. This bolts to the bulkhead with the dead shaft passing through the whole assembly into a captive nut in the opposing bulkhead. There is a hefty allocation of weight up front but I feel pretty confident driving this into even the most fearsome of horizontals with glee.
I have two of these robots to make, one for myself and one as a commission and a total of 3 drums to prep. Looking forward to having this hot potato back up and slugging.
Taulman 910 chassis has dropped courtesy of Ranglebox - feels a lot stiffer than the Esun nylon I used on MotherLoader and the print was a lot cleaner (another big shout for tree supports)
With the drum installed it is feeling pretty tough at the front - also featured on my bench are my HMT stickers I finally had made - an homage to my RW days.
Back to ant business - I slotted in the electronic package of 150mah lipo cells, a Malenki Nano and non name blheli brushless ESC. It sports two Turnabot N10 motors which are 700rpm (fast by my standards). I’m actually making two of these simultaneously, one for me and the other for Matt at Team Croc. Same weapon just he has quicker drive motors, one of the slimline Malenkis and a proper, respectable brushless ESC from BBB.
With a pair of Sad Ken lego wheels it is comfortably in weight. Wraparound HDPE armour and bolts for the weapon teeth are still to be added but it should slide in under 150g.
Working on evil twin ready to ship off to Matt at Team Croc. First time working with the new slimline malenkis and it was super neat having the two power terminals which made tagging off the BBB esc super easy.
Super impressed with both of these bad boys - the BBB weapon esc has excellent settings making spin up really nice and punchy without an aggressive brake when ramping down. Might have to grab one of these for Hobgoblet too! I drafted my forks and printed them in PLA-ST. In an ideal world these will be titanium so when I get enough things racked up that need to get cut out thin sheet I’ll rattle them out. Until that point it will be consumable plastic. 3 bolts lets you change them out every fight.
HDPE wraparound has started and it feels nice and pliable next to the polycarbonate. I am adding a bit more ‘bulge’ around the wheels to give it a little bounce and roll when it lands or gets hit.
Spins pretty fierce without being an uncontrollable mess of mass!
Hobgoblet Mk2 ready to disappoint at the BBBB (the extra B is for BattleBoats) at the weekend. Lacking the colour sadly but it looks pretty mean and tryhardy in the black and white so it’s staying for now.
The armour is all 1mm HDPE bolted down with some cool super low profile head M3 bolts I snagged from aliexpress to make up change on and order but seem pretty useful for avoiding pull-through in plastics. The forks are 2mm ABS and the lid is 1.5mm
For anyone super curious this is how the drum goes together. It is deceptively simple and hopefully robust - though I am slightly disappointed in the play from the bolt shaft. As it is stainless it isn’t ground like a standard shoulder so its a bit sloppy and there is some resistance in the drum assembly. Ah well it spins when I hit the go button so it can just self clearance for a couple minutes before I drive myself out! I may have a hunt for better alternatives or (ew) make a custom part.
And as a bully bonus, it scrapes under the weight limit. The old one was in the ~136gm range and I have easily added 40gm of additional hardware so all the scrimping and tweaking was absolutely essential.
I feel pretty confident this is objectively a better robot than the first one, but I have a sneaking suspicion it will not perform nearly as well… Not trying to hedge my bets here, just slightly aware I may have made it worse by making it better.
In the end Hobgoblet never got a run out as me and the Mrs caught the sun really badly and couldn’t make it to the BBBBoating event which was a big sad. I wasn’t entirely happy with it as I hinted before but Matt’s copy seemed to be handling itself well through a couple of competitions so I had some notes to improve.
They stayed notes until a couple days ago when I was inspired by Jack’s wonderful GetGot so I stuck on some death grips and knuckled down to put my plans in to practice.
The aim is to cut weight out, get space for a bigger drum swing and increase the weight over the wheels to get it driving a bit better - though the last version was pretty good in this regard with the battery right up the back. but I do like me some indirect drive, even at 150g. I wanted a more aggressive stance for the robot too, something a bit Brazilian in nature.
There are two N10’s right at the back which drive the wheel through spur gears. There are two bearings in each wheel. I’m planning to make the chassis out of something like nylon with the wheels being TPU to take a bit of abuse. I have some foam rubber coming in the post which sits over this to form a tyre.
Two single cells sit flat in the core of the robot and the ESC’s fit on top of them. The switch and charge port is still up in the air but I imagine its going to be in the top left hand corner. I am probably going to add in some geometry to protect the gear a little but I’m not going to go mad with the wraparound armour. Part of me is leaning towards a full TPU frame with a fat wall and higher infill to just tank hits.
The main point of improvement was ditching the shoulderbolt which was stainless and not on size. It’s been a well observed cheat that you can run bearings on shoudlerbolts as they are ground and hard-ish but not below 6mm it seems. The M4 with a 5mm shoulder all seem to be stainless and are really undersized which leads to a lot of play, over ~50mm that means it can just clash with the stator. Not great. I just ditched this entirely and replaced it with a length of 5mm silversteel. This and a better shim, a deepened bearing pocket and it’s like butter. If butter span at 18,000 RPM.
Shorter, fractionally wider but lower chassis height. Overall it is a fair chunk lighter already. The drum itself is growing in diameter a little with the M4’s being taken out to M5 so there is a bigger tooth and a more aggressive impact (hopefully)
To prevent sator drag on mine using the stainless shoulder bolt - I ended up having to go down to a very small bearing size that was thin enough for me to squeeze two sets in the driven side of the drum.
That seemed to cut out enough axial wobble to stop that from happening for me.
Although that being said, I would almost certainly go down a custom shaft approach if I were to do it again now that I can lathe.
I keep toying with the idea of buying like a c1 or c0 just to be able to make little shafts and bore out gears. Would make my life so much easier once more.
Luckily this doesn’t need anything custom it’s just a length of ground shaft cut to length with a couple of perpendicular pins to seat it in the bulkheads.
Threaded the drum for M5 with one bolt in to check clearance and it’s looking great. Much more meaty. They’ll get ground down slightly so they get a little more engagement and they don’t clash.
Tyres are done and I’m pretty pleased with how they look. Just the icing on the cake. I’m going to try and get it wired over the weekend and give it a rattle around.
