I am newbie and bought and lathe and accessories from retired guy who was getting out. I have turned about 30 pens so far and I am very critical of my work. Especially when seeing the awesome work you guys are doing. My question is how many pens do you think you get from a set of bushings before they need replaced? I am having a hard time with my pens in that the finished blank and the pen kits parts aren't equal and it is driving me nuts. I am thinking my bushings are worn down. Is there a cheat sheet that shows bushing sizes so I could mic them and see?