While I hate to spend any more time on this angle table than I already did a few years ago, I still will post a bunch of pictures I took at the time to show that I didn't half-ass my attempt to repair the table. It was a fully-assed attempt over several days with not a whole lot to show for it.
My table wasn't from Vevor, but lets face it these are all made in the same dirt-floored factory. This is also the bigger model. I think there might have been a thou or two of a dip in the table in this position, but it was fine. As long as you use the table like this, at zero degrees, you won't have any problems. But that's not why you bought an angle table...
At this point, I could see some problems as the guides weren't at the same height. Unfortunately, I don't own any equipment that can accurately machine this. They didn't either!
Now I'm going to get into how this worm driven angle setter is a very poorly thought out and a complete joke. Notice you can only turn the screw from one side.
You only have access to the screw if you angle the table away from you which sucks for setting-up objects on the table. The mechanism also limits the angle of the table as shown here. The solution is to simple remove the entire worm drive system. You don't need it! If you can lift the table onto the mill you can snug the bolts and easily tap the table to the required angle.
This picture is from an Ebay auction, but this is what a proper angle table looks like. Notice that the crank handle is far away from the table so you can actually adjust the angle without the table getting in the way. This is from Yuasa and, of course, even used it is MUCH more expensive.
Yes, they couldn't be bothered with sanding the tops of the mounting lugs so you nuts get fouled and the table shifts about when you tighten the table down.
Luckily, I was able to reach in with a fly cutter and machine this surface.
Still couldn't hit 45 degrees and found this inside bit needs milled down for clearance. This extra long end mill did the job.
Here's how you set the angle. It's really easy and you don't need the worm gear. Snug the bolts and tap it in. Notice the plastic protractor on the angle table isn't bad.
Now what I found that when the table is set at an angle and you sweep the top with an indicator you get a lot drop in one side. When you move the table in the other direction (closer to the mill), the opposite side drops. I spent quite a bit of time trying to file and sand the top of the base to produce a better result but I didn't get a tremendous improvement and it's still far from perfect.
As you can see, sweeping the indicator nets .015 of difference and this was after I worked on it. I should state that when mounted on the mill the table was zeroed-in via the front machined surface. The more you angle the table the worse the drop gets.
And here's how you "fix" it, you just jam a piece of shim stock between the base and table and tighten the bolts. Several different thickness of shim stock are kept in the box with the table. The further the desired angle is away from zero the thicker the shim will need to be.
What a long-winded post! Hopefully somebody find this useful.