I have been installing hardwood for customers for a few months and things have been going well but seems I met my first challenge. When I installed 4" wide 3/4" thick mahagony flooring there is excessive height difference, maybe upto 1/10 of an inch in rare cases, between adjoining boards.
I investigated and found this is due to the chipboard (3/4" OSB) floor being very rough. Even though there is 1/5" thick plywood on top of the OSB the problem persists. To correct the problem do I sand the OSB floor or smooth it with floor leveling compound? Or is there another solution?