IÂm using up several decades worth of leftover wool tapestry yarn collected by myself, my mother, my grandmother and my great grandaunt, to make scrappy granny squares. I think I have enough to make about 80, maybe more. I make all the centers out of white worsted to get some balance in the finished afghan, and then add four rounds of tapestry yarn. IÂll probably make a final round with white or black yarn so I can sew it together with one single colour.

The problem is that the yarn is in two different gauges, one is like worsted, and the other is slightly smaller. It can be worked with the same size needle, but the thicker yarn is thick enough to make a square with one round of it about 5mm larger than ones made with all smaller gauge yarn. In order to make all the granny squares line up for an afghan, I need to make them all roughly the same size. IÂve never made a large piece from grannies before and IÂm wondering which would be better: to use a smaller needle when crocheting with the thicker yarn, or to block the smaller squares before I sew them together?