I recently purchased a 3 inch rutland cleanout brush for my pellet stove it was about 7 bucks nice brush but when I looked at the extension rods for it I almost died 47 bucks for 4 fiberglass rod that hook together hmm had to be a better solution I guess I'm cheap). Anyway the brush has a 1/4 inch 20 tpi collar attached to it so,seeing as my stove pipe is straight with no bends init I went to the hardware section of hd and bought 2 3 foot threaded 1/4 20 threaded rod and also 2 1/4 20 collars for about 6 bucks . I brought them home and attached one rod to the brush on the other end I screwed the collar on halfway up and spot welded it to the threaded rod. Now when I need to clean out the flue it's just a mater of screwing the 2nd rod to the collar and remembering to turn the brush clockwise(otherwise it unscrews the brush can clean my entire 6 foot of pipe and I saved over 30 bucks.