While Todd, the Aero/Astro shop manager, is your best resource for help when machining things, here are a few things we've learned:

• Sandwich panel delaminates when cut on the waterjet. It's best to start the cut about an inch away from the section you want so the worst delamination won't be on the final piece. It also helps to dry off most of the water, and allow it to finish drying sandwiched between heavy, flat materials.
• To make the centering rings for the motor case (similar to a motor mount, which should link to motor case soon) perfectly concentric, it is best to waterjet them a little large.That way, you can trim both the center and the outside on the mill, which will ensure that the inner and outer edges are concentric.
• Composites, especially carbon fiber, are hard to machine. Dust masks are required, and it's helpful to have a second person vacuum dust with the dry vac as you create it. It's best to use the team's carbide end mills because composites are especially abrasive.
• Always, ALWAYS check to make sure the piece you machined fits where you think it should before marking your task complete. When you figure out why it doesn't, add a lesson learned here