Use higher f-stop, and possibly higher iso.
For example, try f8 with iso of 400.
Take a multiply number of shots to improve your ability to get a shot in focus.
"The subject is not in focus" is a standard response for everything wrong with a shot, including they do not like the image subject.
Take more interesting photos.
The subject in the first photo is the cutting tool on the stone. It is out of focus. The hands are mostly in focus, and the paint on the grinder is in focus. But the cutting is not.
The second photo has an ambiguous subject. None are exactly in focus, making the subject identification more difficult.
You may wish to setup your focus to a single spot, and ...
Well, I can't say for the particular model of your Nikon, but if you have live view, you can zoom in, and check the sharpness of the details of your subject. I suggest trying manual focusing, as sometimes the autofocus of cameras cant identify focus on objects that dont have contrasting edges, such as the spinning disk of the saw above.
Also, if you plan ...