After I cut those my afterthought was actually to use a skew chisel sideways to sharpen up the groove. Maybe next time.
I only recently started turning any kind of plastic. All wood and metal in the past. Interestingly for me there was a little learning curve. Didn’t take long but first stab at plastics yielded some immediately recognizable issues. These are my opinions and what works for me, so take with grain of salt and others with more experience certainly know better than I do. But I started like with wood essentially riding the bevel, gouges etc. No. Not the way to go or at least not for me. Had to change tool positioning and where I engaged the blank lower and take the tact of more scrape/scraping-cut. Also, I had to put all true gouges away. Flat tools and they cut much better if ground or positioned for a negative rake. In fact, I think the negative rake was really a big deal to nice cutting, good ribbons of waste, no chattering, and no chipping. Negative rake and flat topped tools really did the trick for me. Speed is obvious and I go by feel. The carbide tipped tools seem to be my go-to tools while turning the plastic handles right now. Do yourself a favor and start with round rods over square blanks to start to get the feel.
