Having had this issue with my AK, my experience is this is like war, esculate as necessary. 1.The Thor brass or lead hammer first with wheel on ground tapping each ear soundly in succession attemping to break the "set" loose, 2.then penetrating
oil; let set for requisit time; raising wheel off ground to take lateral load off threads(use a floor jack for this) rotating the wheel to get a new "ear' on each blow, 3. the Finish line type or other job defined tool,4. light heat on center face of "knock-on" via small torch or a very directable heat device (do not heat hub itself as this self defeats the process). I've had success and only badly scarred one "knock-on" with this process. The final step is cutting the "knock-on" off and I'd hate to consider this. Recommend you do NOT use a dead blow hammer, do NOT slip a pipe over an ear expecting leverage will do the job (at best you'll break an ear off the "knock-on") Post a sucessful removal:Very liberal amounts of "Anti seize" or "never seize" after cleaing male and female threads with a solvent and tooth brush. Also good to put "antiseize" on face of wheel that mates to hub and in pin drive holes. I've left them on for 2 seasons and 3000 miles and never had to go above level 2. above to remove in a very damp climate. Don't forget the safety wire