Our grandson has a toy car with a centre wheel that requires a pull cord to spin it, it's an old car and the cord long since lost so I designed one for it. I did find one that someone else had made, but the teeth were too small and close together, so I made my own.

Print on its side, already oriented that way, using PLA or PETG. So far it works well.

Layer height, 0.28 for first layer, 0.2 for all other layers.

I've included the step file and Fusion file if you want to tinker with the model, making it longer or shorter or find you need to adjust the teeth spacing, width etc.

Files are provided as is, if you can sell the model then have at it, all I ask is for credit for making the file and if you like my work, consider donating to my coffee fund: https://ko-fi.com/darrengerbrandt