When I got into beetles & feathers in 2018, Crabsolutely Clawful was my main bot, a floppy armed horizontal grabber:
One of my fave bots around the same time there was an excellent US 1lb-er called Free Hugs by Tommy Wong:
I’ve thought about bringing back the horizontal crab grabber arms with 2026 tech some more damage / spice.
(also flirted with the idea of glow plugs with hot wings / buffalo wings)
My pit buddy for Dortmund @teamBotchef had had similar thoughts to me around a dual horizontal - he had some hubmotors kicking about - why not use two?!
Rob’s best known for pizza themed robots including scary horizontal New York Slice:
And as we’ve done many events together and helped each other on our feathers it felt like a good match for a collab! Project: Seafood Pizza. And the deadline would be the next event we could do after the April Dortmund event - MITE in late May.
We spitballed some ideas and sillyness, and decided a chef crab spinning some pizzas would be a fun thematic combo. @Craig helped us out with the name and logo, which he smashed out the park:
As for the build itself - it was quite a good one to collab on as we could break it out into modules we each had more experience in and with the parts we each had laying about - I had drive / grabber stuff and rob did arms weapon bulkheads) & spinny weapon stuff… there was lots of back and forth on ideas.
It was intense timings however, as after Dortmund we had BBB’s BEVs + New blood at LHG to run as well as a workshop move, a gig to put on and other life things so cramming this stuff in was interesting…aaaaaaah
So after we got back from Dortmund (to be clear we’d both ran different beetles there) we started the CAD for Crabba, sending back and forth different bits of the bot between two different cad softwares (probably not advised!).
Parts list was some old Max mk1s w/ a catalyst for drive. Repeat servo for grabs. 35A ESCs & hubs for spinners. Separate receiver for weapon operator. We then had a test PLA chassis:
Inspired by old crabsolutely we tried out RC car linkages for the grabber:
but all the M3 hardware felt like something I could easily bend by hand and wasn’t going to hold up to 2026 level spinners
So instead having seen thingiverse models for a servo rack and pinion, I tried out a TPU double helical rack to give the mechanism some flexxxx to help reduce servo stalling and shocks from hits to the arms:
A second one on top pulls the other arm the opposite way.
Keeping things true to the OG crabsolutely, Rob designed the arms to use 20mm HDPE to take the hits but to fit a hub motor in it, he designed a sandwich of two 10mms with a wire routing pocket through it - so plenty of CNC action required. He did some tests of the fits with some PLA arms, and tested the ESCs / spin ups clamped to the workbench.
Around this time we had PoM, just with a stubby armed pizza-less lad with foamies for wheels:
Custom ESC labels were essential, obviously.
A week later we got together to combine bits with the proper parts - TPU chassis, HDPE lid & arms, Hardox forks & discs, and it was starting to have some proper character!
It spun nicely and made quite the noise in the test box.
One theme park trip later, we felt weirdly on schedule, so added some nice to haves - very chunky TPU / molded PU wheels for a bit of armour & grip. Pizza box locking bars, because ya gotta
Final assembly and Tx setup was in the airbnb the night before the event. Rob had painted the discs as pizza slices and printed a chef hat to complete the look. Craig helped us with the eyes, The lad was ready for service
Obligitory airbnb group photo with the boys @Nick_DSC @Craig it really did feel like 2018 was back.
At the event (as we’d only just got the bot properly together the night before.. we discovered the bot was 1205g… which was very unexpected, so plenty of weight for improvements - probably bigger arms for bigger spinners and wider reach as well as longer forks, bigger wheels for more clearance etc. We’re running it at pub beetles next though so none of that is important for now and we’ll run some plastic pizzas instead.
In terms of fights, we’ll get to that when there’s footage, but we had a very fun day at a nicely ran event with good pals. Crabba mostly performed well with lots to do for both the driver and the weapon operator - the surprise for us was getting best design award, thanks MITE gang!
