Can I actually get flour from my Corona Mill? What mill next?

I bought a Corona Mill and I got it for really cheap, so even if all I can get out of it is cornmeal and peanut butter, I won't be disappointed. However, I was expecting to get at least passable flour if I ran it through a couple times. I am using hard red wheat from my local health food store, and grinding it several times. I end up with meal that has some flour in it, but is mostly sand sized grains of grain ;) I am wary of tightening the coarseness adjustment too much and damaging the burrs. Any advice?

I'd love to use this one for a while before I commit to a more expensive mill, so I'd appreciate help figuring this out. But my next step will be to get a better mill. I am very tempted to get the Family Living mill because I can get the adapter for my Kitchen Aid and can also get the rollers and flakers later. The next option that I like (probably the best) is the Country Living Grain Mill. I like that because it is beatuiful, well respected, and durable. It doesn't adapt to other things as well, but it would certainly turn out the flour I need! I don't think that I would be able to justify any of the models that are more expensive than the Country Living mill, so it won't help to recommend the $3k models :)

-Toby