Drilling holes to reduce frame weight: best pattern

[MrForbes]

I second the hole saw recommendation. Notice I started by suggesting 3" holes....

[FrankJ]

Originally Posted by MrForbes

I second the hole saw recommendation. Notice I started by suggesting 3" holes....

[Sardonic Irony] You don't have a 3" step bit? [/sardonic irony]

[InFlight]

One of the easier ways to drop weight is to switch from CIMs to Mini-CIMs. You can drop 0.6 lbs. a motor. The two have very similar torque at 40 amps, the Mini-CIM just doesn't have as high of a stall torque.

Might be easier than drilling that many holes in your frame.