How to Snap a Diagonal Chalkline

Philip Carpendale of Nelson, British Columbia writes:

If you’ve ever tried to snap a diagonal chalkline across a piece of plywood, you know how frustrating it can be. Past a certain angle, the line’s hook just won’t hang on to the edge of the plywood. To deal with the problem I use a utility knife to make a small nick in the edge of the plywood.  Then I slip the string into the resulting slot. Now the string hangs on while I snap my line.