You know, you should try rolling the axle on a flat surface with the end with the cone hanging off the end. You might find it's bent and you're wasting your time. Freewheel axles usually are bent in my experience.
If you have to buy an axle kit you'll get new spacers and locknuts anyway so why bother borrowing a pipe wrench?
Save the dustcaps, they might not be the same outer diameter but the inner diameter is almost certainly the same.
If you feel you need more strength, Niagara and Harriscyclery both have solid cromoly axles.