Marshall Hardware: Located in Duluth's Lakeside, Marshall's has everything (or almost). If you have an older home, this is definitely the place to find the materials you need. Plus they are well staffed and VERY helpful. You won't have to track down an employee for assistance like you do at so many other hardware stores these days.
For details, http://hardwareduluthmn.com/ or https://www.facebook.com/marshall.hardware