There are two co-workers who work the graveyard shift. I never see them since I work from 8-5. There was an issue regarding over time and since has been reduced to 8 hours of over time per employee instead of which ever employee wants to take it. Because of this, two co-workers are conspiring to get me fired. I built something out of scrap metal that was going to be thrown out, and worked on it only during my lunch hour or when I was clocked out. I never used company time and I only used parts that were scrap. These two employees took pictures of it and stated to other co-workers that if it comes up missing they are going to say that I took it. I am just trying to figure out if it is legally my property, and if these guys can do this. I have a feeling they are going to take it, report it missing and try to blame me. What shoud I do?