Bellmouthed holes are caused by misalignment of the reamer with the hole. The use of accurate bushings or pilots may correct bellmouth, but in many cases the only solution is the use of floating holders. A floating holder will all movement in some directions while restricting it in others. A poor finish can be improved by decreasing the feed,but this will also increase the wear and shorten the life of the reamer. A worn reamer will never leave a good surface finish as it will score or groove the finish and often produce a tapered hole.