Abrasive Cutoff Saw Issues

Thanks Steve, and everyone else who helped me on this as well. I picked two other wheels, both of them Nortons, but the thicker model (89359). The vibration was greatly reduced, and my cuts improved, but it still felt a little "loose".
I decided to do some measuring, and what I found was that the wheels themselves are not in a perfect plane, but they have some error in them. I determined this by measuring the runout of the wheel at the circumference. By loosening the mounts and rotating the wheel; no matter where I rotated the wheel, the error occured at the same place each time.
What I also noticed, however, was that the error would be decreased or increased depending on how I rotated the wheel, which suggests that something besides the wheel is contributing to the error (the shaft arbot isn't true).
Considering these two error sources, they are magnified by the flimsy nature of the machine itself. Holding the base with one arm, and rocking the motor/blade assembly with the other, there is a large "twisting" motion observed, due to the less than optimal solidity of the machine.
In other words, I think it's a cheap piece of tin that isn't fit to rotate a 24oz 14" disk at 3600RPM, much less create anything approaching a square cut, and that is the significant source of my problem.
So, it's back in it's box, with the receipt in my wallet, and will be returned to HF. I'm going to exchange it for their model 1624 (on sale) which, from what I can tell in the store, feels a heckuva lot more solid. At least I hope so.
Jon

Jon, among other endeavours, there is one particular act for me that led to lasting happiness. It involved no psychics and no meditation.
What made me very happy was replacing my abrasive saw with a cold saw. It was a profound transformational event.
As for abrasive saws, my experience with a cheap one was not too good, as mine burned out in the middle of making a trailer. So buying something more expensive is justified, I think that you are on the right track with returning your cheap saw.

All of the saws I owned were Makita. Other major brands are good, too. I even used most cheap wheels, but there were a brand or two that just weren't very good. Consider biting the bullet and getting a brand name. Or get two or three or four cheap ones in the same time span. The good ones DO cut a slight bit better, having better jaws systems, IMHO.
Steve

If I ever hit that damn Lotto thing, I think the first thing I'm buying is a cold saw. They are a pure D pleasure, aren't they?
Steve

My cold saw is a little baby cold saw. I believe that it has a 10" blade. It is small enough that I can lift it if I need to. It cuts metal cleanly and (relatively) quietly.

My "new" saw is a 10" Delta chopsaw I got at the pawnshop for 35 bucks , meant to cut wood . I'm using 5-for-$4.99" HF 7" abrasive cutoff wheels . It ain't optimum , but with a total of 40 bucks invested , it'll do for now . It makes better square and miter cuts than my portaband-in-a-homemade-stand , which is the reason I bought it . Might borrow (doubt he'll sell it) a 10" cold saw from my buddy BillTheMachinist . Time will tell - if I need it he's already said I could use it .

I sure would like a cold saw, but for now I'm limited to an abrasive saw for my cutoff needs.
Speaking of which, I returned the flimsy unit and bought the HF model 1624 (on sale for $110). It's good points include more weight (42# vs 36#) a much more rigid motor to table interface, and a much stronger motor; it also has a way to loosen the mounting bolts and adjust the arm angle to ensure that the blade is at the proper angle WRT the table and work. The plug-in cord is 14 gauge, (other saw used a 16 gauge cord), which is nice to see.
On the few cuts I made yesterday, they were all square, and the tool didn't seem like it was about to bend into a pretzel as the other one did. Additionally, the motor didn't bog down on the cut, but kept right on spinning into the cut, the way I would expect it to.
The downside is that the threaded clamp thing is a POS, and is pretty much useless for anything other than a 90 degree cut on square stock. Not a big deal for me, as the miter fence is sturdy, and I can just clamp my material to the miter fence like I probably would anyway. The angle marks on the miter fence are completely useless, as I expected, but then again it's no big deal to use an angle finder to make sure that miter cuts are done to the desired angle. Oh yeah, the "1 inch arbor" is actually a 1 inch bushing placed on the 1/2" shaft from the motor, but it didn't seem to cause any trouble.
So I'll be keeping this one to use as my cutoff saw. It is about the minimum I am willing to settle for as far as quality goes when spinning a 24oz abrasive disk at 3800RPM, and as long as the motor doesn't poop out on me I'll continue to be happy with it for my purposes.
Thanks again to everyone for guidance on this, I'm glad I ditched the first unit.
Jon

There were a lot of those bearings used in old computer printers. The wide carriage had lager sizes, and he faster printers had more than the cheap printers. I have removed a lot of them and reused them over the years. I also have a car door hinge repair kit I bought years ago from JC Whitney that has various sized sets of bearings & pins.