You will need to pull the line out and hold it tight between the two points of measurement then snap it to leave a mark. Some chalklines have a pointed case to double as a plumb bob.
It is a great tool when you need to mark a straight line, whether you are creating a design you plan to paint or need to cut wood or wallboard.
Here are some quick tips that will help you keep things straight.
Usually you need another person at the other end of the chalkline. But if you are working alone a temporary nail can be your best friend. Simply tap it into the spot you want to set your chalk line and hook the chalkline to the nail.
One problem with chalklines is that the line often leaves a heavy layer of chalk dust, and the chalk is messy. It can get on your clothes, hands, and materials where you don't want the chalk dust. If you leave excess chalk on wallboard, for example, it may be picked up in your latex or other paint, and be carried all over the wallboard surface by the paint roller. Or, if you use the chalk line to mark the walls for installing a suspended ceiling, you will most likely get the chalk on your hands and spread it over the acoustic ceiling panels. So here’s another tip. Before you “pop” the line to leave your mark. Pop it first away from your project, that way the excess chalk dust won’t get all over the area you want to paint or cut. You can also take a new chalkine, one that doesn’t have chalk in the case. In an area away from your project coat the line or string by hand, but only coat the length of string you need to mark your line. This will help keep excess chalk to a minimum.
Chalklines can come in handy but if you don’t use care you may end up creating more work for yourself than you planned. Be careful and enjoy the project you are working on knowing you are doing your best with a chalkline.