I bought 6x6 L Brackets and had major fitting concerns. From my pictures you can see the post are larger than the inner bracket hole. I am using pressure treated lumber from Lowe’s. I had to chamfer all the post edges and reduce the post thickness by 1/16” on the sides. Even with this modification the welds on the inside reduce the overall dimension to less than 5in! I contacted Toja Grid and they blamed the pressure treated lumber being swollen. Even if a dry “true” piece of lumber was used, with the welds, you would need to chamfer all the wood post edges to make it fit. It’s just a poorly designed part to not account for the tolerances of both the bracket and lumber. As an aside, all the Chinese branded brackets sold all over Amazon all fit properly. Upsetting at the fit of these brackets for how expensive they are. Beware if you are looking to buy Toja Grid. They were not helpful when I outlined the issues.