Recently I have been working on the attach fittings. These are the tabs that are attach to a bolt that runs through the spars and are the attach points to the landing wires (wires that hold the wings up) and the sway wires (wires that stop the top wing centre section from moving laterally. Check out the journey that I have been on reading the the post on the design and location of these things.
As far as building is concerned I notice I am getting much faster at producing steel parts. I have the cutting down pat, the linisher makes the edge finishing really fast and the quality and consistency is getting better too.
Here is a pic of the fabrication part way through. The small ones are sway wire attach and the large the landing wire attach.