I made this table completely out of pallet wood. We have true 1x4 pallet wood which is hardwood. for the legs, I doubled up 2 pieces of pallet wood for strength. Every piece of wood is a 1x4. It turned out perfectly as I needed a narrow table for our 2nd-floor hallway.
This took us a little longer than with cut lumber as there was a lot of planing and sanding since it was pallet wood. If we had used lumber it would have taken a few hours less.