when not sure on a machine.....I just find a ruler that I can place so I can see where the 1/4 would fall...there is usually a mark there on the machine but not always...you can also just measure and put a little stack of sticky notes on your machine to help you guide your fabric or a piece of tape....but the gold standard is to actually piece some of your cut out fabric together as directed and make sure the finished size is what it is supposed to be.....