115" by 115" on my Kenmore UltraStitch (33 years young!). It was Dunsters' Diamond Log Cabin pattern, and came out awesome. I started with the centering the middle section on my backing, with a 50" square of batting under it, basted down. When I had that all quilted (SID around every log), I added the rest of the batting, the next round of diamond logs, basted and quilted that. Then added the next round of diamonds and the corners, quilted all that. Yep, had a sore back at the end, but it may have been from self-patting it! Now I feel fearless on the smaller quilts, hee hee.