This website always helps me when i have problems so heres a new one. I thought that by switching from hummel to floorcrafter would solve my problem with waves. In exchange i got chatter that i can buff out.
My refinishing jobs look flat as granite when i stain them but when applying the 2nd coat of poly i can see slight wave patterns in the right light (because i am bending over and inspecting my work during application). Usually a real thick final coat will fill the voids but im always shooting for a perfect floor. I know water popping will help hide imperfections to the clothed eye but i recently refinished a 1000ft, 80 year old w.o. floor. The customer specificly requested early american NOT water popped and the floor was one of the best floors ive done. I sanded it with my floorcrafter with 40 grit and then 80 grit on the FINE setting. Then buffed with 1w0grit screen. Hope this info helps me find a consistant refinishing results

How are you applying the finish? If you are using a roller, this may be the cause. Try using a t-bar or a lower nap on your roller cover.

Yes i prefer tbar over roller. Ive noticed i get less wave when i sand new wood compared to refinishing. I know it could be that floor is loose or my machine is following the waves that are already there. But i always do my first cut at a 15-22 degree angle to get the floor flat.
I have never had to resand a floor because of it. I know my floors look good compared to some of the pictures on here about waves. Like i said its not seen by the clothed eye, im just trying to perfect my craft.

Thanks for all responses

I've always sanded to 100 grit with the big machine. A smoother floor is easier to clean. It comes out a little lighter color when stained than 80 grit, I suppose, but I screen the floor with 100 grit screen, too.
Finish is expensive, so smoother surface takes less finish to get a smooth floor.

Adjusting your grits will not remove a wave. The wave in your sanding could come from loose flooring, roller application, big machine wheel or wheels out of round, "herky-jerky" walking behind the big machine (especially if you use a waist belt), and I'm sure there are other potential causes too.

I had a friend who refinishes help me on a monster sand. (I sub contracted the staircase to him)
He uses a floorcrafter the same way i do and he says what i am getting is more of a ripple than a wave. He suggested investing in a multi sander like his bona multi sander. For his final cut he does 60 grit and then 80 grit before he stains. I already use the ceno satellite. But 80 grit alone already leaves a bad scratch pattern. Any suggestions?

I also agree with using a tbar over rollers for application

T-bar or rollers work well as a lambs wool applicator. The sanding technique that uses an angle on all the cuts, even 7 degrees may help with your problem. This will even help remove previous drum marks from the last poorly done job.