Make sure you dont hit the axle with your hammer.. Tighten the bolt to were the axle is just below the bolt surface. That way when you smack it.. the end of the axle doesnt mushroom out..
If you deform the end of the axle, you will find it VERY time consuming to file/retap.
HEAT is your friend.. even a small propane torch will do wonders to free up things! Just be careful not to over heat sealed bearings,dst shields are plastic and melt!