My lathe isn't bolted down. I never did. Mostly because I'm lazy and once it was there I was done. Lol. Other reasons include needing to be able to slide it out slightly to get to the motor height adjustment in the back if I changed the motor pulley, and also because I wanted to try to mitigate excess vibration from traveling through the bench into the floor/house.
Okay, so I'm going to assume the bed is in fact straight. If my little level is showing a discrepancy, I can't see it...
I suppose the next step is to look into the head alignment?
Actually. I think I have a great test for this possibly... I watched Adam booth make some metal feet for his new welding/work bench. He faced off a 2 something inch piece of bar, and found a concave when he put it on his surface plate. Showing either wear in the cross slide or the head alignment. I can do this test too. And it'll finally give me an actual job for the surface guage I made. If I can remove any taper/concave/convex in that method, it should be head alignment, correct? If I cannot remove it and it just goes all catty-wompus, then I have cross slide wear, then I can also recheck the carriage. Same with that. If it does all stupid and I cannot get a consistent reading or it varies, then it was wear all along.
Also, identical wear existing in the cross slide as well as the ways is probably unlikely. I can compare the two surfaces. If they are alike then it's alignment.
Ok, ok. A whole bunch of possible tests are popping up in my head on being able to figure out if it's alignment or wear. I'm gonna stop writing and test those out shortly. Just need to finish up a welding job.