This is a drop spindle for making yarn. This spindle is designed to be used with a 3/8" wooden dowel. You will also need a small 5/8in cup hook to go on the top. See images.

Also included is a tool to help you install the cup hook. Basically you push it on the dowel as far as it will go. Then insert the hook into the hole. Twist the hook all the way down. Then remove the hook, and the tool. Reinsert the hook in the hole. This should give you a very centered hook and a well balanced drop spindle.

I printed mine with the infill to 60% to give it extra weight. You can adjust it to suit you needs.

Any questions, please feel free to post in the comments.