I don't do a lot of turning but yesterday I needed to rough out a cylindrical blank at school when I had a couple of spare minutes. In the mornings this time of year I normally wear a fleece vest under my shop apron, and in about five minutes of turning, my apron, vest, shirt and T shirt were full of chips. I had to make a quick trip over to the air hose to clean up.
Today I needed to do another quick turning job, and I left off my apron (and fleece) and grabbed my welding jacket. It's cotton, size XXXL, and has a stand up collar with a snap tab. It worked great as a turning smock; nothing got past it or down the neck. It's a REVCO welding jacket and a google search will take you to Amazon where it's around $30 bucks or so. It's also a decent welding jacket, and it has no pockets on the outside to fill up with sawdust.