Re: [mowbot] Re: Gotta have gas to cut ??

Dave Everett (deverett nospam at
Tue, 11 Mar 1997 10:30:36 +1000

Byron A Jeff wrote:
> Well with Ken's encouraging words I decided to try my first experiments
> at developing a cutting system. So I set forth with the basic idea of
> a DC motor that spins the cutting disk.
> The problems now:
> 1) The plate really isn't attached to the shaft so while it spins there really
> isn't any power to it.

When I was looking for a way to attach things to a motor I came accross
something at a local hobby store that might be helpful. Modern radio
control cars use universal joints to transfer the motor energy to the
wheels. These universals are made of plastic and splined to take brass
inserts with different holes sizes and grub screws. I chose an insert
with the correct hole size for a motor I was using then tapped the other
end to take a small bolt. The wheel I was using was then attached with a
spring washer and was really very tight and strong. Another way is to
use a large short bolt. I initially attached the weed trimmer head to a
motor by this method.

First I clamped a peice of particle board to the plate of my bench press
and drilled a hole through that was the same diameter as the bolt I
wanted to use. The drill bit was removed and then I hammered the bolt
through the particle board. I then changed the drill bits to the motor
shaft diameter and drilled carefully down into the bolt. After that was
done, I removed the bolt and drilled a grub screw hole in the side of
the bolt head and tapped it.

It still vibrated a tiny bit, I think due to the imbalance of only one
grub screw.

Dave Everett.