I've made several tool holders for my lathe. I've always used HSS dovetail cutters and it seemed to take way too long. I've seen tutorials on YouTube where they make indexable carbide cutters. I have a bunch of inserts that I had no use for, so it seemed like a good project. After I finished it, I made a holder and was impressed with the way it cut. I didn't push it real hard. I was advancing 0.025 per pass. That was more aggressive than I do with a HSS cutter. Today I decided to see what it could do. I finished the holder in three passes. 0.100, 0.100, and 0.037. It seemed to handle it fine. I'm impressed. The material is 4140.