Abstract: A frusto-conical trowel apparatus for smoothing mortar or plastic lining material in a pipe or conduit or other such object which has a generally cylindrical inner surface. The trowel body consists of a plurality of laterally overlapping plate members which are mounted onto an inner frame at the small end of the trowel body; such inner frame and it's support bars being enclosed in a conical device to prevent mortar from entering the trowel body; having small rods connecting a spring member to the inner frame while allowing the spring member to reside at the large end of the trowel body and provide pressure against the trowel plate members in order to establish compressibility diametrically of same, creating needed radial troweling pressure.