i just purchased a k-380 drum machine for my root problem. it seems to me the cutterheads i recieved with this machine are much too small to use on a 4 inch mainline. is there another cutterhead i can use on this model? any suggestions or advice concerning this matter would be appreciated. i also did what you guys suggested and purchased the ROOT-X to use after cleaning the line. please leave a part number if there is something to attach to it. thanks alot.