When screwing in the top cap screw into the star nut it emerges from the fork at an angle and not dead center and parallel to the fork. Is my star nut out of alignment? How do I remedy this?

you could thread the bolt in without the cap and tap it gently till the bolt per perpendicular with the steertube.

Tried tapping it into place but the star nut has gone too far down.

Believe you meant parallel with the steer tube.

If the old star won't come out insert a new one above.

You have two options at this point. Easy and hard.

1) Easy: Smash in another star nut and make sure it goes in properly
2) Hard: Smash out the old star nut, you'll need to typically do this from the underside of the fork (you may not be able to do this depending on the fork you have)

This is of course assuming the entire steerer is steel/AL. And not say on a sleeve inserted into a CF steerer like some Cervelos.

In general, it really doesn't matter as long as you're able to set preload. Do you know the correct procedure and are you able to set preload?

Steering tube is made out of steel.

I think I'll just bang another one in at this point.

I'm not entirely sure what preload is TBH.

Heh.

That's what the starnut allows you to do - the bolt that goes into that starnut compresses the entire headset stack allowing zero play in the system = headset adjusted.d

Okay, I'll just push the original star nut through with the aid of a dowel and a mallet. Then I'm going to order the park tools guide with another starnut and go from there. I appreciate the help.

Instead of pushing the star nut down further and installing another, you could just get a longer bolt to reach the original one, assuming you didn't knock it way down in there.

Save your money.
Go ahead and push the old starnut out the bottom. Then re-insert this "used" starnut to the correct depth using a stem bolt or slightly longer bolt (longer the bolt, the easier to hold alignment), holding the bolt plumb with the steerer tube while tapping it in.

Assuming his fork even has such an opening or it's large enough to go through.

Before doing anything, learn what preload is.

Use a longer bolt and just use the original star nut where it is now. Then go to the Park Tools website and read up on how to properly adjust the stem cap for preloading the steering bearings.

I see what preload means now.

Is it possible to reuse the starnut if I push it through? (BTW it is possible to push it through with my fork)

If using a longer bolt should I just directly tap the bolt in order to align the nut?

Most of the welded forks I've seen pinch in at the bottom so the star nut will be ruined by punching it through. The only ones that seem to be constant all the way are some of the older pressed in Marzzochi MTB forks. Check your own and measure it to see if pushing it through is possible. Too many variables to say either way without seeing it.

Yes, if you use a longer bolt you just need to tap or pry the bolt so the star nut kicks over a little and the bolt sits in line with the tube. There's enough play in the threads that as long as you get it close enough by eye it'll be fine.

This.