"machined pulley" is one of those terms that comes up on forums like this more than it comes up in actual shops. If a brand new Delta pulley has a noticeable wobble, it's time for some diagnosis.

What's the history of this saw? Was there a time during your ownership of the saw when the pulley didn't wobble? Is it possible that the bottom shaft is bent, for example if the saw fell over? Is the shaft or keyway badly worn, filed, or damaged?

To answer your original question, Grizzly has what you want. Your local electric motor rebuilder can get them too. You would just need to measure the bore and diameter of the pulleys that you have. However, you should get to the root cause of the problem before ordering or the pulleys may be no more successful than the link belts.

Pete