Torque required for hammer to self right?

**typhoon_driver** · 23rd December 2012, 16:58

As I said before, do the sums and work out which motor will work best for you. Then design the machine around it.

**Coolspeedbot** · 30th May 2016, 09:24

Would a normal cordless drill motor do the job as a axe motor if it is geared correctly?

**maddox10** · 30th May 2016, 10:24

There is only so much power in a batterydrill motor. Gearing won't amplify it at all, just make it a tad more efficient.

**RogueTwoRobots** · 30th May 2016, 10:41

I used a cordless drill motor as an axe motor on a 5:1 ratio. In short, no. There are small steel pins inside the drill gearbox that keep the small pinion gears in place, and the forces from a weapon like that just cause the pins to fail (basically falling out of the holes in which they're mounted).

If you want to go for an electric axe, have a look at electric scooter motors on eBay, specifically around 300-350W power rating. I changed my drill motor on the axe to one of these and they are vastly superior. On the same ratio the axe hits a lot harder and faster, and the motor can definitely take it. Sam also uses one for his robot Hatchet and has it working well for him.

**Coolspeedbot** · 30th May 2016, 11:07

I see, what exactly does the 5:1 ratio mean? I would guess small gear to big gear type of set up.

**RogueTwoRobots** · 30th May 2016, 12:50

Yep, the drill motor had a sprocket on it with 8 teeth, and the axe had a sprocket with 40 teeth on it, connected to each other by a chain. So for every five rotations of the drill motor shaft/sprocket, the axe arm only rotated once, thus the 5:1 ratio. It reduces the speed but increases the torque (or turning force) so that it isn't as much of a struggle for the motor to turn the heavy arm.

**Coolspeedbot** · 30th May 2016, 13:07

Oh good, I guess there will be some modding to fit the small sprocket to the motor.

**Coolspeedbot** · 31st May 2016, 09:48

Originally Posted by RogueTwoRobots

I used a cordless drill motor as an axe motor on a 5:1 ratio. In short, no. There are small steel pins inside the drill gearbox that keep the small pinion gears in place, and the forces from a weapon like that just cause the pins to fail (basically falling out of the holes in which they're mounted).

If you want to go for an electric axe, have a look at electric scooter motors on eBay, specifically around 300-350W power rating. I changed my drill motor on the axe to one of these and they are vastly superior. On the same ratio the axe hits a lot harder and faster, and the motor can definitely take it. Sam also uses one for his robot Hatchet and has it working well for him.

something like this?

http://www.ebay.co.uk/itm/24-VOLT-30...AAAOSwBLlVcco6