The suicide knobs/steering wheel spinners are pretty easy to install. Some machines will have less space between spokes and will need a smaller knob. My DGKs love the machines I set up for them to use. As a safety precaution, I would be sure to find a finger guard to put around the needle even though it isn't fool proof. It is easier to get the eyes off the needle when they are using a hand wheel to turn the machine.