An apparatus (501) for manufacturing a filter rod for a smoking article comprising a filter plug (101) having a plurality of threads (103) extending through at least part of the filter plug. The apparatus comprises a tapering duct (511) having a first open end (511b) for introduction of filter material and a second open end (511a) for the expulsion of a formed filter rod. The tapering duct narrows from the first end to the second end so that as filter material is conveyed through the tapering duct it is compressed to form a filter rod. The apparatus also includes a plurality of feeder tubes (554a-c), each feeder tube to introduce a respective one of the plurality of threads into the filter material. The apparatus further comprises a guide duct (518) adjacent the first open end of the tapering duct to guide filter material into the first open end of the tapering duct. The guide duct is a separate component to the tapering duct. The plurality of feeder tubes extend into the guide duct, each feeder tube introducing a respective one of the plurality of threads into the filter material as the filter material passes though the guide duct. Also disclosed is a method of manufacturing a rod for a smoking article.