What would happen if I used 5/8€� threaded rod as a wheelbarrow axle?

I need to replace the wheel on my wheelbarrow. The wheelbarrow is used for
light duty homeowner tasks, like yard work, not for hauling concrete or
bricks.

All of the new wheels have a 5/8€� ID for the bearing, but my original axle
is just over 5/8€� and doesn't fit into the bearing. I can get a 3 foot
piece of 5/8€� solid rod for $8-$9 or I can get a 1" piece of 5/8€� threaded
rod for $1.50. Since both of them need to be cut, that's a wash, so I'm
really just trying to save a few bucks as well as being curious.

Will the threaded rod chew up the bearing casing? The wheel I plan to use
has a built-in grease fitting if that makes any difference.

My other option is to grind down my original axle on my bench grinder. It
won't be as rough as the threaded rod, but it sure won't be as smooth as
new solid rod. As a test, I ground down about a half inch on one end and it
will fit if I keep going. Obviously, that's free, other than my time.

I'm still curious about using the threaded rod though.