Some of the newer Triumph use titanium valves. There must be a way to get Ti to resist ignition. The combustion chamber is a very hot place.
Looking down on the lathe from a bird's eye view, the bit holder centerline axis should be 90 degrees to the rotational centerline of the part with insert tooling, as shown in the first photo. It should not be at an angle like in the second photo.
Looking down the rotational axis of the part, the top of the bit holder should be horizontal and at the same elevation as the rotational centerline as shown in the third photo. The typical tool holder used for HSS steel tools, as shown in the fourth photo, is not suitable for insert tooling.
These are general rules and there are exceptions, like cutting tapers.