The hacksaw will often damage the last thread when it cuts. Running a nut off the end will fix this. You'll have to run the nut all the way down from the other end. This doesn't take long, if you chuck up the rod in your drill and let it do the work. Hold the rod vertically, with the drill pointing down, and just hold on to the nut enough to keep it from spinning.
Mine is similar but a bit more robust. The top is a sandwich, two 18mm sheets of WBP ply with an 18mm mdf filling. The legs are mortise and tenoned together, the ends glued and pegged, the stretchers are joined with long bolts so it comes apart. I stiffened it by adding a very closely fitted cabinet underneath (it had to go in dead square) and it is now absolutely rock solid.
Grizzly is a company currently undergoing an upheaval. This brand was once known as a manufacturer of professional grade tools and equipment for woodworking products. Though, in recent years, that reputation has begun to slip a bit since being bought by the Chinese company SIEG. These days, whether the Grizzly product stands up to its previous standards of excellence often has more to do with what you are buying than the company itself.