Are you turning the but the right way? Often the nut is reversed thread

 

Your nut probably has been on a long time, so it has grown accustomed to being there.

A thought , are you sure that you are turning it the correct way?
Some are left handed thread, do you have access to a manual, maybe look it up online.

Are you changing a wore out blade, if so you might use a vise -grip plier to clamp on the blade to hold it from turning while using a socket and breaker bar to unscrew the nut.


ED

 

Every blade I've changed have had left-handed threads. Use the vise grip and turn the other way.

Jaz

 

Thanks! So turn it the opposite way the blade is rotating?

 

Yes, turn the nut clockwise if it's left hand threads. You should be able to "see" the threads by looking closely at the exposed threads of the shaft. But pretty sure the threads are left handed. The reason is to prevent the nut from loosening by its self as it's used.

Jaz

 

Got it! Sure was on there tight. Thanks!