John I've also noticed that you have to push them a bit harder which is why they get hard to control A spiral blade should not be pushed at all merely steered in the direction you want it to cut, of course there is always going to be some pressure on it but you'll find the less the better, one other thing I've noticed is there will be a lot more fuzzies when your blade gets dull as its not cutting clean. So these are some things to look for and if I may quote Pete they are only 30 cents a piece throw them away. Why are you using spirals John? not that there is anything wrong with it but when you first learn you generally start with straight blades so much easier.
Not criticizing your decision I was only curious maybe some of the other member could comment on this I personally find it strange. All the best John with your new hobby and keep the questions comming
.../Hans