I'll let y'all in on a funny secret!
I'll ram a piece of stock into a three jaw chuck, and go to town on it, way sooner than reach for a four jaw chuck.
I have it, I use it regularly, and it can be your ONLY chuck, pretty easily, but I also understand when it might not be the fastestest, easiest, choice!
I just know, that you need to have stock, larger than the finished diameter of the final part, and that you need to be able to do as many of the required steps as possible that relate to concentricity, in one operation, without removing the piece FROM the three jaw chuck!
Once you take a skim off the outside of the bar, your stock is as centered as it can ever be. Unless you release it from the grip of the chuck!
So, understanding the series of processes, that are required, to reach an acceptable end result, is the entire key, to being able to make a great part, out of lousy stock in a lousy chuck!
I LIKE my four Jaw Chuck, but my Three Jaw scroll chuck is faster and easier to use, much of the time, esp. when the bar being used as stock, is large enough to allow a skim pass to true it up, AND the part can be almost completely made, in one set-up!
But, you must have a pretty solid grasp of the sequence of operations, to get from bar to part, first, so as to be able to plan the operations, to NOT, back yourself in to a corner!
How do I get from here to there?
How do I support the part while it undergoes knurling?
Which Operations are hardest? Should I do those first, so I can start over sooner, or do I leave them until I have considerable effort invested, and THEN put my part at risk?
Every part made, is a series of simple operations, no matter how the end product becomes complicated. Turn a diameter. Place a shoulder or shoulders, in the correct place. Create a thread. Champhers. Counter-bores. Recesses. Material to support the work with a center, while it gets beat on by a knurl tool.
A fella has to be practical sometimes. When you understand how you are getting from 'here' to 'there', you get to map out the trail you will take.
There is seldom only ONE path, that will get you to the end goal. You can do it this way, or that way, and they are both (all!) correct, if the end result is a part that fits where it is needed, and does what it should!
And that's me waxing philosophical, for tonight! LOL!