Looking at the web site, it looks like some of the holders have built in side and back rake, and some do not.
Most "friendly" materials can be cut without back or side rake. In some materials it works quite well. In lower horsepower machines, it limits how much you can cut. Other materials, especially on a small lathe, they really want some positive rake.
I'm gonna link you to the middle of a video. It's worth watching if you ever grind your own tools, or maybe just to have some idea what the different angles do. (And just how ugly a tool can be and still work perfectly, provided all the required angles are there). Anyhow, the spot I linked to, (30 seconds or so?) there's some really good (dirt simple) drawings there in the first little bit. Might kind of help with a mental picture of what the chip is doing, and why one might want to select different back and side rake angles.
Most "friendly" materials can be cut without back or side rake. In some materials it works quite well. In lower horsepower machines, it limits how much you can cut. Other materials, especially on a small lathe, they really want some positive rake.
I'm gonna link you to the middle of a video. It's worth watching if you ever grind your own tools, or maybe just to have some idea what the different angles do. (And just how ugly a tool can be and still work perfectly, provided all the required angles are there). Anyhow, the spot I linked to, (30 seconds or so?) there's some really good (dirt simple) drawings there in the first little bit. Might kind of help with a mental picture of what the chip is doing, and why one might want to select different back and side rake angles.