A good starter set includes three chisels between ¼- and 1-inch wide, and you can always supplement with additional paring or mortise chisels for specific projects.

Best for Beginners: DeWalt Short-Blade Wood Chisel Set Best Bench Chisel: Ashley Iles ½-Inch MK2 Bevel-Edged Chisel Best Mortise Chisel: Narex Mortise Chisel Set ...

With a wide bench chisel, clean up the sides of the mortise. Don’t try to remove all the waste at once. Take small cuts. Use a narrow chisel to square up the ends of the mortise.