Star nut keep coming out!
 

So I finally got my rigid fork to replace my suspension fork. However upon tightening the top nut onto the star nut, it is lifting the star nut out of the steer tube. I don't get it. Do I have a faulty star nut or am I doing it wrong? I have not tighten the stem bolts yet.

btw, the star nut came with the fork.

Is this on a used fork? Simple solution: remove old star nut and install a new one.

Star nut installed upside down? They have a bit of cup, and if wrong side up the wings on
the nut won't dig in on compression, but slide.

The star nut you're trying to use is likely for an aluminum or size-down-from-yours fork steerer. Swap it for one a size larger. It will need to be pounded in with an installer tool (to keep it straight and at the correct depth) and a mallet.

It might just be shagged out. If so, you can prolly tweak it good again with some pliers.

Like pry out the "wings" of the nut?

Let's doublecheck that we're loosening the stem bolts before tightening the top cap.

OK, got a new star-nut in. It is nice and snug. However after tightening everything, the headset feels loose?

In post #1, you mentioned that you didn't tighten the stem bolts yet, so it sounds like you understand the top cap bolt needs to be set to preload the headset first.

Is there a gap between the top of the steerer tube and the top of the uppermost spacer or stem (whichever is on top)? You need 2-3mm there to ensure the headset can be preloaded adequately before the top cap butts up against the steerer.

^ What do you mean?

Should the steerer be jutting out 2-3mm above the stem or vice versa to preload the headset?

I believe it is flushed with the top of the stem.

stem needs be proud above the end of the steerer tube, though a spacer above the stem is as good.
star nut needs be inset down the steerer tube ~6 mm .. if Further in .. just get a longer bolt ..

Vice-versa. The steerer must end below the uppermost spacer/stem. If the top cap butted up against the steerer, how could the bearings preload? For an extreme example to make the point, what if you had no stem or spacers; the headset would be super loose because there's no way to compress the headset.

Top cap needs to be pressing down on either the stem or a spacer rather than the steerer in order to preload the bearings.

Thanks Jive and Kimmo. I didn't know that the top of the stem must be a bit higher than the top of the steer tube. I thought it needs to be flushed together. I will try it later today. Hope that is all it is.