What is the smallest or largest size paper I can use with a corner rounder?
This depends on the corner rounder. You will need to read the “specifications” on the corner rounder to determine the minimum and maximum size of paper that can be cut. Most corner rounders can easily handle small pieces of paper. The dimension you will really need to look at is the maximum paper size. Although many corner rounders can still cut larger size paper, many make it much easier by including a large base to help support the larger paper.
