Sail Making - Long Arm Sewing Machine This custom designed long arm is over 2000mm (79") long with 700mm (27.5") underarm clearance. The head is a modified Seiko 263skz, where the upper part with the needle has been physically separated from the lower part with the hook. The two parts are synchronized through the use of servo motors, as is the puller. An operator interface allows for total control of the machine.