Hi Leon,
First off staggering work! What a beautiful car you are building, you Kiwi's are the most CAN DO/WILL DO poeple I have ever seen. I have a question/concern I bring up only for safety reasons so please know that it is not to slight the beautiful job you are doing in any way. I have been in the aircraft industry for 25 years most of it in Manufacturing Research and Development and there are small things when working with aluminum that can be a very big deal. The way you deburred leaving scratches will be the first place a crack will start, stress riser. Whenever we get a nick or scratch in structure it must be blended out or replaced so the deburr tool would be a much safer way to go. If you look at the pictures Kiwi Ka posted in post 183 you can see that almost all the rivets used are driven universal type rivets. The reason for this is that they provide both clamp and hole fill while being driven and therefore much better in fatigue. Pop rivets and enen Cherry Max hole filling rivits don't even come close to the strength in either shear or tension. Big pain to drive them all I know, I built an all aluminum airplane a few years ago. The other thing that I think is very critical can also be seen in post 183, the front suspension/shock attach point as well as the rear arm of the upper "A" arm attach point is certainly 4130 Chrom Molly. The loads that will be transfered in this area will be some of the highest in your car and I don't think the aluminum structure you currently have is going to fare to well. I hope you will take this in the spirit it is given, I thought long and hard before taking the time to write this because I trualy love what you are doing and think your skills and attention to detail is surperb! I just don't want to see your beautiful work of art have a suspension failure that could be terrible to say the least. I can't wait to see your future post as I love to follow what other fabricators are doing, your car is fantastic and I can't wait to see it finished. Thanks for sharing your project with us,
Steve