the way i've found to do it is like this, if on the bottome side of the terminal, there is a small slit, take a HUGE set of pliers, ones about 12 in long, but designed to fit around bid bolts and nuts and squeeze down on one side of the slit, and press it down a little bit, then take the pliers and now squeeze the other side of the connector on top of the other side you just pushed down...then just squeese the 2 as much as you can. it shouldn't be that had b/c of the torque you can produce from the long pliers. i can do 8 gauge with small needle nose.