KMT Fly Press

A fly press is a type of screw press in which the screw shaft is driven by a flywheel or a pair of fly weights at the ends of a bar. The wheel can either be cranked by hand or driven by a motor using a friction coupling. The wheel is weighted so its momentum will maintain the motion of the shaft.It can frequently be used to punch holes in sheet metal in one operation, rather than by cutting the hole by slower drilling / milling operations. If used for piercing holes in sheet metal work, the fly press tool itself consists of a punch and clearance die, into which it just fits.The bench press beat flys in terms of average muscle activation for all target muscle groups, including the pecs: see the data below. Flys did stimulate the biceps more. Interestingly, biceps activity was actually likely high enough to stimulate muscle growth with the flys.