Occasionally, I have a need to hone a hole to a little bigger size or clean rust or gunk from the inside of a tube. Using a piece of rod 1/4 to 3/8 inch in diameter (even the shank of an old bolt with the head cut off), use a hacksaw to cut a groove down the middle of the rod about 3/4" to 7/8" long. I've even made a length of allthread work. Using one inch wide emery cloth that comes on a roll like machine shops use to polish crankshafts, slide the end into the slot in the rod and wind the cloth around until you have the diameter you need to do the honing, then tear off the remainder. Winding it clockwise as you are looking at the slot end of the rod will insure that when you spin it in your drill motor, it will not unwind. Presto, a variable diameter hone, depending on how much cloth you wind onto the rod. If you have a 1/4" drill motor, then use a rod 1/4" in diameter. If you have a 3/8", then use 1/4", 5/16" or 3/8"rod.