Titanium is a misunderstood metal. Rarely is titanium machined in its pure form. Its rather gummy. Probably the most popular alloy is 6Al4V, 6% Aluminum and 4% Vanadium. This alloy makes it much harder and easier to work. People tend to think because of its high strength that it is hard to work.
Well, its not. As long as you keep some things in mind when machining it, it will machine no worse than stainless.
First, Titanium is a terrible conductor of heat. What does this mean? Heat builds up on the cutting tool edge and is not sinked away by the material. To alleviate this you need to use a slow SFM to keep the rate down. Also carbide tooling will help here if you want to get things done in a reasonable amount of time. For example, when I machine a 1" bar of 6Al4V I start out about 700 RPM using carbide tooling. 300, for High Speed Steel. Coolant helps if you have it.
Seconds, dont dwell. Titanium work hardens in the blink of an eye. So if your tool rubs and does not cut the material will get hard and now you are in for some fun. If you machine has power feeds use them.
Last, watch out, titanium swarf is a fire hazard. Dont let it pile up under the lathe. Keep sand or a dry type fire extinguisher around.
It also helps to have a rigid machine. Not absolutely necessary though.
Machining Titanium on my CNC mill:
Finished ring:
Anodizing Titanium:
One neat thing about titanium and niobium is they both can be anodized to just about any color without any dyes. Titanium takes on a color depending on thickness of the oxide layer on the surface. There are two ways to do this. One is to heat the item. Second is with electricity. I use electricity for the titanium rings I make for people. To do this you need a power supply that will go up to about 150v DC. You want an isolated supply as well. If your power supply is not isolated you can use an external isolation transformer. My supply consists of a 0-140v, 3A, variac fed by an isolation transformer. The output of the variac goes through a bridge rectifier and is filtered by a large electrolytic capacitor. The capacitor is not necessary. All of this is mounted in an old 19" rack mount case.
I use TSP as an electrolyte. Use a small non-metalic container with water and a little bit of TSP. You will need a cathode, I use some Ti swarf from the lathe, clip it to the negative terminal. I then use a hanger made from Ti wire to hold the object I am going to anodize, this is attached to the positive output. Put the item in the solution with the power off and the variac at 0. Turn on the power and start turning up the voltage. Around 16v or so you will see the Ti start to change color to a kind of yellow-tan. As you increase the voltage the color will continue to change. Stop when you find a color you like. Bubbles will form on the surface of the item being anodized so I agitate the solution while anodizing.
Here are some rings I have anodized: