No, for this problem, you don't need precise measuring tools though you need to tell the difference between 30.2 mm (about 1 3/16") and 34 mm(about 1 5/8") neither of which is close to 1 1/4". If you're trying to measure for a headset and you can't get closer than 1/16", then you need to measure more precisely. If you do much bike maintenance, then the ability to tell the difference between 3/16" balls and 1/4" balls may become important. If your current tools don't allow you to tell the difference between 30.2 mm and 34 mm with ease (about 1 3/16" and 1 5/8"), then an inexpensive and precise tool may be useful.