[Steven Smith]

As many others have said, build using what you have experience working with and tools capable of producing with.

In 2014, my first build season with the team, we had a "basic" shop with drill press, chop saw, small manual mill, etc. Most everything was COTS and we used a lot of VersaFrame product.

Since 2015, we rely on our in house CNC router for large flat parts. In 2015, we used a lot of aluminum tube profiles (1x1-3x2 OD, walls of 0.0625 to 0.125 and everything in between), with custom made flat pieces like gussets, larger panels, etc. Our elevator carriage still used a bit of VersaFrame. Our drivetrain was manually milled tubes for chain in tube.

In 2016, we acquired a manual brake (thanks 2848!) which let us make more complex geometries using our router and more precise sheet metal bends. Our robot is one of the more robust out there, and we are nearly 100% rivet construction. We learned the lesson of moving to 5052 for bending. We also saw a lot of good examples of polycarb usage for mechanisms that bend instead of break, most notably (to us), 1477s intake in 2014, which inspired a lot of polycarb usage on our robot as ball guides, intake mechanisms, shields, etc.

Next year, we plan to use many of the same materials and techniques, and add better jigging to do aluminum tube extrusion bearing holes and lightening patterns on our CNC mill, as well as gearbox designs. The existing gearboxes are all probably better quality than what we can make, but some years the packaging flexibility of making something slightly different would be nice.

Outside of all that, we use a laser cutter to make Delrin spacers in house for cost savings and use 3D printing extensively (ABS/polycarb).