the robart jig I have will just center the hinge on the piece being hinged up to you to drill the hole perpindicular.I took a 3 ft long piece of mdf. 4"wide added a 1"high fench on one edge then used a square to draw some perpindicular lines from the fence.for strip type surfaces I place the te up tight against the fench put the jig on where I want the hinge and using the drawn lines as a reference drill the hole.