I attempted a first part last weekend on the mill. I used Fusion 360 for the CAD and CAM. Here is the part on the fixture plate:

Attachment 391296

This stock is 1" x 1.574" x 4.074" 6061 Aluminum. The odd dimensions are so it can be clamped on the fixture plate. The fixture plate has holes every half inch. Some are reamed 0.250 and most are tapped 1/4"-20. There are three pins that hold the part for reference and 3 MiteeBite clamps with 1/4" screws to keep it from moving. The clamps specify 0.301 from the center of the hole to the edge of the clamp and the pins are 0.125 from center of the hole to the edge. MiteeBite says shims can be used but this being my first attempt I didn't want to deal with another variable. Milling and spot drilling went well. The drilling not so much. This was the third op which was drilling with a #9 drill bit to a depth of 0.7". I used the Rapid Out Drill cycle. Should have used Deep Drilling (Peck Drilling) cycle. Here is why:



The bit made it 0.6" before the spindle ran out of power and stalled. Then during the retract cycle it yanked the part out of the fixture clamps and the spindle started spinning again heading back to 2500 RPM. The part was very imbalanced and the rotation quickly caused the drill bit to snap and the part to get thrown. It made a nice dent in the Z axis ballscrew cover...

Attachment 391292