How to stop wheels spinning off their output shafts and Brushless drive

[Danjr1]

Good afternoon,

Two questions:

My bot's wheels keep spinning on the output shafts so I'm planning to take the inside shoulder off all my wheels and drill through the wheel hub, 3/8 unf nut and motor shaft to either install a bolt or split pin. My question therefore is whether to use a bolt or split pin? My gut is going for a nut and bolt but wanted to see what more experienced roboteers might think.

Second question is related to brushless drive. I've seen some sensored motors on Hobbyking that produce 350w and, through a 20:1 gearbox on 80mm wheels, would run at 15mph. Thing is that these motors are rated at 2s so I'm wondering whether this could potentially work even if the voltage is very low compared to what's been before?

Cheers

Dan

[maddox10]

I wouldn't recommend drilling trough the output shaft of a drill. Seen it before, and it will give a nice weak point that will snap.

On brushless drives. 350W/7.4V= 50 amps. 50amp esc's needed...

But I think it will work nicely. After all, Hannibalito3.2 drives on 3S with 28mm diameter unsensored brushless motors.

[Danjr1]

Unless people know of another method to secure a wheel to a 3/8unf thread, I'm gonna have to do it for Portsmouth.

[RogueTwoRobots]

Do you not have reverse thread screws for them?

[Danjr1]

Yeah but hasn't really helped. What I might try is putting a little grease on the reverse screw head so that the washer between the wheel and the screw doesn't grip

[Garfie489]

Might sound abit basic, have you tried putting more washers on? - Defector has 6 on each side.

[Danjr1]

Will give it a go. Two washers with grease between them sounds like it could work.

[Ellis]

Don't grease them. You want the complete opposite: the normal thread and the reverse thread bolt need to be locked hard to each other. The idea is if one starts to rotate the other locks up. Try some low-mid strength thread locking compound and crank them up hard.

[Danjr1]

Cheers Ellis!

[Ellis]

I wouldn't use much on the wheel's threads (if any) as if the gearbox goes it'll be a massive struggle to remove it, but the reverse threaded bolt could benefit from some. The suggestion above of sturdy enough washers, so tightening up doesn't flex them, is a good one.

edit: although 6 is overkill lol