DIY Welding Table - Made the entire table from scrap plate and pipe I had laying around. It may have been easier to buy the top plate since I had about 3/4"
Learn from Engineers - Making the Dream Welding Table | Fractory
Do it yourself Welding Table with Sliding Extensions - YouTube
DIY welding table (16mm clamping holes) with accesoires | 3D CAD Model Library | GrabCAD