You may find it helpful to hold the leaf chain cutting tool in a vice, as this leaves both hands free to handle the chain and position the clamp screws.

Leaf chain cutting tool

Screw back the pusher screw, making sure it clears the clamp area. Clamp the chain using the clamping screws, ensuring the chain pin is aligned correctly.

Leaf chain cutting tool using clamping screws

To check alignment, unwind the top clamp and gently turn the tommy bar until the pusher pin appears and is on the centre of the chain rivet pin. Once aligned, wind the top clamp back until it covers the pusher pin. Never attempt to break the chain unless the top clamp completely covers the chain pin.

Leaf chain cutting tool top clamp

Turn the tommy bar in a clockwise direction. As the pusher pin forces the chain pin through the press fit outer plates you will get stiff resistance. Continue until the resistance stops and the chain pin drops or appears from the bottom of the chain breaker.

Leaf chain cutting tool chain pins

Screw back the pusher screw and release the clamps and the chain should separate.

Leaf chain cutting tool release