I needed a tool to hold the bottom of the blade assembly of my Santos blender to be able to undo the top nut with a socket wrench so I could clean the whole assembly properly.
I made this spanner to fit in the bottom and enable you to hold the bottom steady in one hand while undoing the top.
Use no skirt as the handle has rounded edges and may meet the skirt while being built up / printed.
40% infill worked for me and was easily strong enough to do the job. 30% may work?