A guidewire system configured for introduction into a body lumen, comprising a core wire having proximal end and a distal end and a tapering profile, and a micromachined tube coupled to the core wire, and a joint where the micromachined tube is joined to the core wire; the location of the joint being at a location on the tapering profile where the torsional force which can be transferred by the core wire and the micromachined tubing are substantially the same.