I still got to drill out the weight supports for the hinge pins, but wanted to wait until I got everything welded on, the part of the hinge that welds to the tank was pre drilled and I used a length of 1/2" round bar and slid it through the outer pin holes to make sure all pins would line up. So now I just use the holes in the tank side hinge to center my bit and drill it right on the tank.