I use both carbide and HSS, and I like both. I switch between them as I work. Sometimes I use the the carbide when I am lazy about sharpening the HSS tools. I have three of the full-size Rockler turning tools: Square Radius, Round, and Diamond. They are good, but not great. I bought them because I like the way they feel. They are on sale now through 30 January 2020. They go on sale from time to time through the year.
Here are a few hints about carbide turning tools, based on my experience with the Rockler carbide turning tools:
* Carbide tools and corresponding tips come in different sizes. I have the full size tools, but I could have bought "mini" versions, or even smaller "pen turning tools." The carbide tips on mini and pen turning tools are smaller than the full size tips. The smaller tips let you turn finer details, the larger tips are useful for larger turnings like bowls. I use the full size tools with the larger tips on pens anyway, and they work for me.
* The tip must match the tool. You can't put a round carbide tip in a square handle, for example. That's because the end of the handle is shaped perfectly to engage and support the back of the tip.
One exception:
You can fit a square tip in the square radius tool. It isn't a perfect fit, but it is so close that it works. You CANNOT fit a square radius tip in a square tool, however.
* Carbide can get pretty sharp, but high speed steel (HSS) tools can be made sharper. The HSS tools don't stay sharp nearly as long as carbide.
* My Carbide Sharpness Cycle is:
- A short period of amazingly sharp.
- A very long period of "Sharp enough to use, but not as sharp as I really like. That's carbide. Get over it."
- A short period of "not quite dull enough to rotate yet."
- A brief period of "what is wrong with my turning today?"
- Followed by rotating or replacing the tip.
* You can extend the life of carbide tips by flattening the backs on diamond stones and waterstones. It works okay for me. Not quite a new tip, but pretty darn good.
* You don't have to buy carbide tips from the original manufacturer or seller. There are very good third-party sellers - search for them. I have used Arizona Carbide in the past. It is a small business owned by good people:
https://azcarbide.com
* Everyone says that carbide tools can only be used as scrapers. I don't believe them. Sometimes I reposition the tool rest and use them in bevel-rubbing mode and they do well. They can cut long sexy ribbons just like HSS turning tools.
* I have never found a consensus on which carbide tools are used for what. Some people use the square radius tool for roughing and the round tool for finer work, while others do the opposite. Find what works for you.
* The square tool is tricky. The corners can leave lines on your turnings without a lot of practice. The square radius tool is much easier to learn. I would recommend a square radius tool rather than a square tool. You can try a square tip in the square radius tool.
* Some people make their own tools and buy the tips. Sometimes they buy the metal portion but make their own handles. I have seen some amazing turning tool handles!
* Shop around!! There are worse tools and better tools than the ones I use. Do your homework!
* The smallest turning tool sets do not always have all carbide turning tools. Several sources sell "pen turning kits" with two carbide turning tools and one HSS parting tool instead of the usual diamond carbide tool.
* Links
Here are the carbide turning tools I use, for reference only!! The same tools are sold under multiple names (e.g. Savannah). I chose them not because they are the best carbide turning tools, but because I like the way they feel in my hands when I work with them:
https://www.rockler.com/full-size-square-radius-carbide-turning-tool
https://www.rockler.com/full-size-round-ergonomic-carbide-turning-tool
https://www.rockler.com/full-size-diamond-ergonomic-carbide-turning-tool
Sale until 30 January 2020 (Latecomers: They will go on sale again from time to time):
https://www.rockler.com/rockler-promotions/current-promotions/carbide-turning-tool-promo
I hope this helps.