These are designed to be put on 2 by lumber found at a hardware store. The opening therefore is not 2 inches. It will be hard to push onto the board. This is by design. To prevent the hook from slipping off the board it is made to be hard to push on. If your having trouble pushing it on rock it back and forth while applying pressure. I don't recommend using a hammer to get it on.
The heavy duty variant is capable of holding 50 pounds at least I have not tested it for more than that. The light duty version is meant more for extension cords and will not hold 50 lbs. due to its shape and design.
To handle the 50 pounds (heavy duty only) without breaking you must have these print parameters:
If you want to see anything else made like this such as a broom holder version (https://www.printables.com/model/512462-2-by-lumber-clamping-broom-holder) leave a comment and I will see what I can do. No promises.
The author marked this model as their own original creation.