Free Materials Need Suggestions On How To Use Them Steel Angle, Plate And Aluminum

The company I work for gets a lot of equipment that's crated up in angle iron frames. Mostly 2"x2"x1/4" thick. These are mostly about 3' long and 20". We also get a fair amount of 1/16" thick "tubs" they are 3'x20"and 2" deep. Lastly we get a lot of random pieces. For example I grabbed a couple 3'x4"x1/4" pieces of steel plate yesterday. I also snagged a couple pieces of extruded aluminum roughly 4'x3.5"x3.5". My 10 year old daughter is actually the one pushing me to help her build something. As you can imagine it didn't take much for her to talk me into it lol. Building things and spending time with her are my two favorite things (and most expensive haha). With all that said I'm not much of a "planner/designer". Usually I just picture something in my head and start plugging away at it. We are wanting to build a benchtop milling machine but I'm thinking it might be best to start off with some kind of. I didn't know if anyone could post some pictures or links to some machines built using angle iron and steel sheet? Also I will post some pictures but I could use some suggestions on what to do with this aluminum. It seems like it would be perfect for something. I'm just not sure what lol. I was thinking that I could possibly add some steel angle iron for strength and then attach the rails to it for the frame. Any suggestions?