To Boat Seats, Benches, Barstools, Boxed Dining Chairs, Etc. Upholstery needles, tacks, staples, scissors, etc. are sharp.
Staples guns are powerful enough to penetrate hard woods.
The needle on an industrial sewing machine is as large as a finishing nail. Use eye protection where appropriate and needle guards if recommeded with your sewing machine. Secure your work. You're more likely to injure yourself on a small job like putting a button in a pillow than in a chair. A dining room chair seat can slip easilly while you're stapling it if you're not careful.