I'm going to post a tool list for airplane building very soon on my website, N2Charlie
But in the meantime, two things that have helped me out recently...a quality angle drill...I love this tool as it allows me to get into very tight spaces. The bits are threaded and you get them of various lengths and sizes to match up to the job...in this case a one inch #30 bit to get a hole in a tight corner. I bought this at The Yard Store and it cost about $240...worth every penny. I bet I will use this a minimum of 100 times building this airplane. At the end of the day I'm going to end up with an airplane with a value over $60,000...a $240 tool is worth it.
This second tool is something I picked up a while back and I made the handle for it, it's for rolling out dents in sheet metal. Sure enough I kinked the skin for the horizontal stabilizer...used this to roll it out and you can't tell where the dimple was. It is a Shape Tip Tool, LT790, from Lock Technology Inc.
