aromakr,
That would be a Simonds brand file, not Simmons. Sandvik also makes a good file. I know cause I pushed them across lots of steels working in the aerospace industry for 12 yrs. Hard to beat a Nicholson though !!!
The chalk absorbs any oils that are on the file and keeps the metal from sticking to the file teeth. It also preloads the valley at the bottom of the file teeth so the filings cannot get pinned in the bottom of the file teeth.
When using a file just make sure you clean and chalk the file before, during, and after use and it will serve you well. Worst enemy of a file is not cleaning and chalking it. Also if you are in a high humidity enviro like I am in TN, I even WD40 my file when I am finished with it. When I want to use it again I dip it in acetone or alcohol, clean with a file card, then chalk it up and put it to work. Sweaty hands will rust and ruin a file before you know it. JMHO
nocams