Is this what you are looking to replace Jeff?
http://www.pbase.com/dennygraham/image/121615912 Here it is drilled out. When the ball stem is peened over it forms a head like a rivet
because the arm is chamfered. After drilling most of the center out I then used a large
chamfering tool to remove the head, being careful not to get into the arm:
http://www.pbase.com/dennygraham/image/121615915/largeFrom here you can drive the ball out with a large drift pin.
The replacement ball is threaded and I used a large flat washer to span the chamfer
in the arm.
Denny Graham
Sandwich, IL