We made dextrous tweezers which consist of two 1 DOF compliant fingers perpendicular to each other. Here we call them ortho-tweezers. Strain gauges were used to monitor the deflections, forces and part rolling angle. The ortho-tweezers are dextrous and robust in manipulation of submillimer-sized parts, even without closing a sensing loop. The ortho-tweezers by themselves can pick-and-place and roll parts. With help of a few fixtures on a 3 DOF Cartesian stage, the ortho-tweezers can reliably pivot and regrasp the part by continually applying contact forces which greatly exceed micro-scale adhesion forces. By measureing contact moments on the part through strain gauges, we can tell whether the part is aligned with a wall. For the demonstration of these techniques, a structure was made by bonding micro-parts using UV-glue. By arranging a bunch of miniaturized ortho-tweezers, it could also be possible to operate parallel assembly with only one XYZ Cartesian stage.