Well, I finally STFW'ed... Got some good, model-specific ideas from the myriad times this question had been asked before. Put a new, decent blade on (not a WWII, but the Freud TK960 I picked out seems to be well liked by people before they suck it up and buy a WWII, and I could actually afford $35), aligned it as well as possible, made a crazy zero clearance insert for the thing...
After spending a few hours reading about the Skil 3400 table saw, I see that I would never have gotten one if I had had a clue, but OTOH people have made do with these things, and perhaps if I make a new MDF or torsion box table for the thing I can get some more use out of it to tide me over until I'm out of debt and can buy a real saw and a shop to put it in.
It's still far from a precision machine, but it's considerably better than it was, and that tap and die set box I made today is the nicest thing I've ever turned out. I haven't managed to cut a perfect 90-degree angle yet, but ripping has improved dramatically. Clamping pieces back together to check out the gaps, I only see the tiniest glimmer of light, which is a big improvement over 1/32" gaps. No scorches, almost perfectly smooth cuts. I'm sure it looks bad compared to a real saw, but compared to what it was, this is night and day.
The one thing that puts it all in perspective is some post I made five years ago, shortly after I got the stupid thing, when I was talking about what a joy it was to own, and before I had any idea what precision meant:
Most important factor for me was price though... I got mine for $50 new in the box on clearance at Wal-Mart. Schweet...
Sure it's a piece of crap, but at least I only paid $50 for it. Most of the other people complaining about what a piece of crap it is paid up to $200 for it.
That helps somehow.
No, it's not a good saw, but I can make do. It's a lot better than nothing. It only took one day of dicking around with a circular saw, a 4' straight edge and a bunch of clamps for me to decide to try again to try to get some use out of the poor little Skil 3400.
I still plan to gleefully throw it into the street one of these days, and let a truck run over it.