Abstract: Apparatus having telescoping box-like cage sections and capable of raising a person or object to a desired height and solidly supporting same at such height, the relative movement of the sections being guided by pre-loaded rollers bearing against vertical guide surfaces provided by the flanges of angle iron members forming the vertical edges of the cage sections. A method is disclosed for assembling the apparatus with the rollers pre-loaded against the cooperating guide surfaces by clamping the angle iron members of the outer cage inwardly before connecting them with cross members under tension.