What am I doing wrong with the feed rate?

[Shotgun]

For me, I got a long thin thread of blue swarf rolling off. Almost like a thin floss.

 

[Lo-Fi]

Crank the feed up if the machine will take it. It's difficult to get tough materials to break chips sometimes.

Stefan gives an excellent explanation of how to get decent precision without "sneaking up" with light finishing cuts which can ruin edges and gives poor finishes:

I really enjoy hard turning. Once you've got your head around the method and that loading it up and running it hard gives the best results, it's really satisfying. The balanced cut method works well on any martial, though.

 

[Shotgun]

Well I went out and swapped the piston wrist pin for an AN-6 (3/8") bolt, then ran through the gear configurations. Man, that made a world of difference.

Still 750rpm, .010" DOC, DCMT070204. This image is

 

[Mitch Alsup]

Wrist pins are universally ground to size, not cut.

 

[Shotgun]

Wrist pins are universally ground to size, not cut.

. . . unless someone is grabbing the nearest available round of steel, and doesn't realize what they're doing

 

[macardoso]

But, why would it cut fine, then finer and then start throwing in random lines?

You lost your cutting edge part way through. Carbide will cut it, but a generic grade and geometry will not hold up for long.