How can I get a hard clear finish on my wood table?
polyurethane is great!
Three coats of a water based polyurethane. Use a foam brush for a smooth finish. Go with the grain.
This article will help you decide: https://www.homedepot.com/c/buying_guide_to_clear_wood_finishes_HT_BG_PA
I have a tutorial that may be helpful all about refinishing wood, https://www.youtube.com/watch?v=Grmaqgb1cbY&t=0s&list=PLhHahKs5Y6UlKfutKv6r0mc-Bqa5UOIVP&index=4
I used automotive clear coat, sprayed on. My son is in auto body repair and was working on a car one day. I just had him spray my dining room table while he was doing his work. It has been working for years, extremely easy to clean and unless you are sawing on it, it does not scratch.