hello
having problem with streaks left after sanding with my floor crafter
60 80 100

Not familiar with that machine but the drum may need to be dressed it may have gouges in it that are transferred through to the floor. It could also be that you are hitting nails or staples that are not set and this will leave a bare spot in the sandpaper that shows up as a streak. Occasionally if we have a floor that is full of staples that have been broken off and are hard to spot we will use a hardplate after sanding or buff extra with screens to remove the streaks. You have to be careful screening if you screen too much you will remove the softer grain and have a wavy floor.