The rollers in each link extend past the outer plate on both sides, the jig comes with a guide which fits over the chain allowing the small pins to protrude through the guide, once all set up it is a simple matter of lightly hitting the pins to flatten them slightly, as the chain is sitting on a hard surface the pin on the opposite side flattens as well, this will lock the plates in place and allow the chain to move freely, it the pins are hit too hard the chain will become tight.
This photo shows the size of the rollers and the different sizes to fit the side plates, these are precisely made and the with the inner and outer plates having a different size hole they fit the shaped rollers perfectly.
Des.
