Trying to assemble a fixture using two v-blocks to align a horse shoe (U) bent tube for machining. The two legs of the tube need to lay in the v-block vees. The inside edge of the cross tube (ringer end) locates against a dowel pin. I've tried picking one side surface of v-block vee and one leg of tube. Using a Tangent mate the tube ends up below the v-block embedded in the fixture base plate. The