Hi
I've been asked to look at 6000 sq ft of site finished north american walnut. The floor is site stained and finished. Has been re done 1 time because of "Waves" in the floor (drum sanded apparently??) Looks like chatter marks to me but I am having trouble explaining dark bands across width of planks. Correspond in general to high points in the chatter. (See photos)
Thanks Steve

I do not see the pictures but the dark bands could be from the straps at the mill and the previous sander only using a light grit to sand the floor.

chatter is real close together, waves are further apart two diffrent animals two diffrent causes. The dark bands are where the finish is pooled up behind the rise left by the machine/mechanic. Is this a rustic floor with a bunch of big knots? Floor will have to be sanded on an 10-15 degree angle to flaten it back down and remove the wave or chatter. Might also consider a trio or 3ds for the fine sanding if you want it dead nuts flat thats what I would reccomend. Also you need to check subfloor floor needs to be fastened properly and run perpindicular to floor joist excess movement can give you headaches as well.