It is not a good practice, but people do it. Some will tap a screw with a hammer to start a hole. Others will drive it all the way in. That is bad for the screw and the wood.
Hammering a screw is counter-productive and will not have good results:
- When you hammer a nail into wood, the sides of the nail compress the wood. The compressed wood wants to expand pressing on the sides of the nail. The pressure keeps the nail in place preventing it from coming out of the wood.
- When you hammer a screw into wood, the threads of the screw "chew out" the wood pressing it downward, possibly compressing it in a downward direction, leaving little or no wood to hold the screw in place The compressed wood, wanting to expand may tend to expand upwards pushing the screw out.
