Orbital sanding question

It's pretty much well known, or at least talked about, that Martin Guitar Company only sand out to 180 grit. This is to assist lacquer adhesion or so I am told. If this is done using mechanical sanding techniques is it really a 180 surface? I've just done and experiment and I only ever hand sand to finish. There are distinct visible sanding lines at 180 that are not 'filled' by the lacquer. Anyone have an answer for this?

Different sandpaper standards? Cami being more course than Fepa in that grit range. Fepa 180 Grit is going to be closer to a 200 grit Cami. I think most often we use Cami, but that is not to say Martin does. Are you sure you are comparing apples to apples?

Also, I can't imagine guys and gals with random orbit sanders working over guitar bodies in a factory setting. They may use a specialized sanders like a stroke sanders.

Sides?

I am using 3M...

Random orbit sanders come in a couple of different flavours. For something like we would use them for you are wanting a "Fine Finish" sander. It will have a much smaller orbit than the more conventional one that is much more aggresive.

Rule of thumb when using Fine Finish sanders is that your scratch pattern will be in round figures 1 grit step finer than if doing it by hand using the same brand and type of paper.

Eg. of that would be if you used P180 on a Fine Finish sander the scratch pattern would be more like P240 if doing it by hand.