How to hold and center work piece

[Cabro32]

I am at a loss as how to mount and center a pitman arm to a rotary table. I want to machine the splines and taper out of the pitman arm.
Thanks
Joe

 

[Cabro32]

Thanks Knudsen and David for the much needed help. Your help gives me a couple ways to work it out. This is my first go round trying to do machining and it makes a person have a lot of respect for you and your knowledge.
Joe

 

[Cabro32]

Rest assured that the pitman arm is just an old part from the junk pile and was selected as a good learning project.