Can't Do It Without Tools
If you want to build a plane, you have to have the correct tools. You can do it with some minimum tools but the more the better. In our case we are scratch building aluminum airplanes and in addition to the normal riveters, fan tools, deburring tools, etc, you really should have a metal shear that can cut at least a 4 foot wide piece of aluminum. We also could not do without a 4 foot break. There a lots of great tools that would be very nice to have but I think we have a decent balance between what's required and what's nice and what we can afford. If you don't have enough tools, you will have a hard time seeing the project through to completion.