We are trying to install 5" Brazilian Red Cherry hardwood floor. The boards are unfinished.

First thing we noticed that the boards' with had a 3/32 variation, so we measured each board with caliper and sort then into 4 width range.

When it was time to install, the first board we tried to put in did not square to the transition board we put in place between the dining room and the kitchen by 3 degrees. Meaning if the short end the board flush with the perpendicular register board, we would have 3 degrees skew, and if we lay the board perpendicular to the register, I would have a triangle shaped space at the short end.

We checked board, and sure enough it was not square, we have checked several more boards, none of them were square, but not to the same degree, some more some less.

Now I am thinking of squaring each board so we can have a floor that does not have triangle shaped space at each joint at the short end.

My questions are:

1. Are the boards are not square by design, serve a purpose?

2. Are the small triangle spaces at each board not a big deal, and after sanding and finishing the floor they will be omittable.

3. If I take may time with squaring each board will we get a better installed floor at the end. (I have done crazier stuff in the past)

Any help will be greatly appreciated. I know it is a hardwood floor, but I did not expect to be this hard.

Background:
- 140 Year old house, bowed kitchen floor both directions.
- We leveled by cutting curved shims every 12"
- We Install 3/4 plywood BCX, and screw them with 4" deck screws at every joint and shim crossing.
- Boards will be nailed with 2" 16 gauge flooring nails.
- Rosin paper between hardwood and plywood.

It will look much better to have the butt-joints meet like they ought to. If you use a power miter saw to make cuts, you could trim the groove end without taking all the groove off so there will still be end matching. Set the saw up for the correct Angle to match and cut every one that needs it.
This is a manufacturing defect.
Your installation of the rosin paper will help control dust and allow the boards to slide into place, but if you would like to have moisture protection from below, I would use AquaBar Kraft paper. Wax between the layers of the thick paper will protect the flooring from moisture..