Axe weapon

[Max]

Hi,
Could you use a drill motor (without the gearbox) to power an electric axe at 12v?
If so roughly what gear ratio would you need for a 30cm long axe with a 1.5kg axe head?

[jonny]

you'd be better off using a more powerful motor but in theory a 12v drill motor could work for an axe if geared properly. it might be better to keep the gearbox on then gear it down again for a small ratio with chain though.

[maddox10]

1.5 kg axehead??? The 12mm axle from the drillmotor will be very gratefull.


In Kashei we use a speed 900, a large reduction gearing, 12 steel arm and a Coldsteel 600 grams Spike Hawkaxehead

And I have to admit, we needed to change the mod 1 steel gears to mod 2, because after a few fights, the gears were wearing down visibly.

[Daniel]

12V drill motor? I'm guess that's a Mabuchi 550 style of motor. 95W at 15000rpm and no load speed of 17500rpm.
My calculations say a 95W motor would swing an axe that big in 0.30 seconds, which is an average of 99rpm. That would need a 150:1 gear ratio to be efficient. A smaller gear ratio wouldn't let the motor spin up to its peak power band and it'll just draw too much current and make everything hot.
A big scooter motor is efficient with a 8:1 ratio, which is why I prefer to use them. And the lower gear ratio counters the extra weight of the motor.

[harry hills]

i'd listen to that bloke, huntsman is awesome

[Danjr1]

its possible if you use two drill motor/ gearbox units. would imagine it would have to be at 18v or above. Robowars (australian website) has a robot with that very combo but with a hammer and using friction drive. It's what i was considering using as i preferred the compact nature of such a design

[mattsdragons]

I've had a quick look an that seems like a nice design, run that at 18v and it could make a good weapon for people that don't want too run pneumatics

[Daniel]

i'd listen to that bloke, huntsman is awesome

You make me blush. Except maybe a 75:1 reduction would work too. Better to leave the gearbox on the motor and then a 3:1 or 4:1 reduction after it. But probably won't self-right easily.

I remember Gary's friction driven hammer, Ball Peen. It actually appeared on Neighbours, so maybe you guys saw it before too. The hammer worked pretty well but I don't remember ever seeing it self right. The friction drive didn't slip but not quite enough torque to lift its huge chassis. He replaced it with a new axe robot called Fragmentor which had a scooter motor that spun the axe through 360 degrees and tended to weld its weapon relay shut. It inspired me to build Avenger after seeing how crazy it was. Damn, that was a long time ago.