There’s a hidden dimension in long arm measurements. It’s the height! Lots of people talk about how long the arm of a sewing machine is. But the height is just as important!  Long arm machines usually list the length AND the height of the machine arm. You can see this in the line up of these Gammill long arm machines below. a a a Long arm machines are listed by length and height 30 inches long by 12 inches tall 26 inches long by 10 inches tall 22 inches long by 10 inches tall 18  ...