FP pivot material

hi all
looking at shedding weight from my hw, flipper pin is 30mm solid steel bar running full lenght of robot chasis and weights nearly 4kg, there are also 3 short bras in the flipper arm, total weight of over 7kg. need more weight for armour. looking at replacing the main pivot arm and one flipper bar, here are some suggestions i have been thinking on all should work due to there material properties just wondered if anyone had any dealings with them.

1, use seamless mild steel steam pipe 3-4mm wall - very strong but expensive
2, t6 ali solid bar 30mm - light but might bend and wear quick
3, t6 ali tube 5mm wall thickness - might fatigue very quick
2, nylon rod 30mm - should just deflect slightly in use self lubing

thanks all

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there are also 3 short bras in the flipper arm

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Must be pretty robust undies to weigh 3Kg :shock:

But depending upon the forces in the pivot I'd say either use steel pipe (seamless or welded, makes little difference) or ally bar. I'd hazard a guess that nylon wouldn't last very long before it shears or gets cut up badly.

If weight is a problem how about using some bolts/setpins instead of a full length of bar? Or as an alternative get your existing bar bored up the center by a friendly machine shop?

Just a thought.

I would bore it out as well. Is the robot running hawker batteries? Thats the first thing I would get out, switching to lithium would save you 8-10kg, should be more than enough weight for armour.

Personally wouldnt use Nylon for a pivot...Some may say its strong enough but I wouldnt use it.

Pivot materials.

Gravity 3 to 5 uses M20 nuts and bolts.
TAN uses CNC milled 7075 ali plates/axles running in hardox holes.

Hannibalito 3 is using white metal bushings in between the steel


But for your application. A steel tube with 4-5mm wall and loads of grease in another steel tube will do.

outer pivot is 5mm wall aluminium welded in the flipper and also holding the robots frame together the pin/bar slots all the way though the robot at the top and is 680mm long. the system works well but like i said before robot total weight is 86kg with gas but, not batteries will be lipo, wiring, rx etc
and no armour.

so only have 14kg for batts, wire ,rx ,flipper scoop and full armour,

so trying to save maybe kg of the bars will free up alot of armour weight

thanks all.

We're talking about Ceros right?

I'd be inclined to get it running first and then see what weight needs to be saved when its complete. In all honesty I doubt anyone would mind you running over weight in whiteboard matches (unless you're talking 20Kg or something) while you're giving it a shake down run.

I'd finish it off and have some fun with it, you'll get a better idea of what it can do and how it handles before you start to re-engineer it.