> Do the chin up bars that lock into the top of a door frame by gravity really not damage the wood?

Do the chin up bars that lock into the top of a door frame by gravity really not damage the wood?

Posted at: 2014-09-26 
We have white painted door frames and spouse uses it daily to workout before work. I have found pencil eraser size spots one on each side of frame that's all. Can be easily touched up if needed.