Does anybody have a method of removing the speed nut on these line trimmers that holds the inner cup up tight on the shaft. I usually don't bother with these things but I pulled a couple out of the shed and got them running but they need the bump heads replaced. People keep asking me for line trimmers and I just tell them they are not worth the trouble when you can get them on ebay for about $150 with 4 or 5 different cutting blades