Slim Margins is a beetleweight (3 pound) combat robot I made for Motorama 2014. Design goals were:
As flat as possible.
Disc hubmotor weapon.
It's record is 7 wins, 2 losses at one event before retiring.
Prior to the Event:
Shock mounted drive motors
Fingertech hubs. I still use them four years later.
Forgot about clearance.
Testing with an old weapon blade.
Lineage
S7 tool steel.
Such a nice blue temper done in the kitchen oven.
With its derpy brother HAMster ball.
Halfway Through the Event
Burned stator winding insulation. Should not have used the pretty green (and low temperature) wire. The ashes still kept the windings separate so good enough.
Dings and dents.
Chooch on the left.
And chooch on the right.
Blade damage. This one tested at 53 HRc.
Later learned that only six M3 screws are not enough.
Too many screws.
After the Event
Frame tweak
Glamour shot.
Shock mounting strategy worked well.
No electrical problems.
Dat crack.
Noted: make frame as one part.
Rubbing as expected, but no cracked magnets.
The crack prevented the weapon from successfully spinning up in the final match.
Crispy wires.
Screw, banged and mashed.
Evidence of pliers marks where I tried to straighten things.
It was originally supposed to be a sphere but I got tired of cutting foam, so I just made the center part and put a hefty chunk of steel in the middle as ballast. An aluminum tube ran through the center to keep it rigid.
You can see it in the middle. It weighed almost two pounds.
The robot used two fasteners total (set screw for each wheel). Carpet tape and fiber back strapping tape was the primary fastener. Most of the frame was scrap half-inch foamboard (stiff paper backed foam). It used a couple of gold sparks, the 33.3:1 variant.
A tail told you which direction was front.
Due to a complete lack of pushing power or other method of attacking, HAMster Ball only competed in two matches at Moto. The first one was against a Weta kitbot which didn't have much weapon range, so it did nothing.
The second match was against a robot with a proper weapon, so it showed off its self-righting ability before getting popped in half.
While I hoped it could have gone against a vertical bar robot, the fact it was able to show off the buoying action was good enough.
