I have been reading the Art of Machine Piecing by Sally Collins. She says to use IBC Super Fine silk pins, #5004 1.25 x .50 mm. She also says to get this thread for the top and bobbin threads: 100 cotton DMC embroidery thread as it will cause less fabric in the seam allowance when it is pressed (for a more accurate 1/4" seam). I am going to try her suggestions, as I have a terrible time with my blocks coming out the right size. It is a really good book and has some very pretty blocks- I am still studying it. I have only had the book for a few days.