I have a floor that was installed with 2 1/4" strip flooring that has apparent milling quality concerns. First, the width of the floor strips varies between 2” and 2 5/16” for boards manufactured by the installer. Second, the end joints are noticeably not 90 degree to the length of the board. They are tight on one end of the end joint and up to 1/16” and more gapped on the other end of the end joint. My questions, what are acceptable tolerances for the width of 2/14” strip flooring and the tolerance end joints. Alternatively, how far can the tolerance be off before the manufactured floor would be considered substandard for a select or better floor.

Not quite sure what "boards manufactured by the installer" means, can you explain this a little more? Also have never heard of or seen a 5/16" difference in board width.

As far as milling tolerances for unfinished strip, I'm not aware of any, although I'm sure the manuf. has a range they stay within. I would guess that their tolerances are fairly loose, considering the whole floor is jobsite filled and sanded. Now the 5/16" width difference is another story, not sure what's going on there.

Also a milling tolerance would have nothing to do with a select or better grade being considered a substandard grade, but rather if the wood had natural characteristics of a lessor grade ( like #2 common ), ie: extensive knots, mineral streaks, worm holes, more shorts, etc.

Thanks for the quick response. To clarify, the installer milled the wood that was also installed. Rather than having a product that was near the 2 1/4 as requested, the boards range from 2" wide to 2 5/16" wide. I can see perhaps being 1/32 to 1/64 off, but a 1/4" is a 20% variation. In all fairness, boards in a row had a near similar thickness. However, you can visually see the difference in thickness along with the end joints that were not filled. End joints that were filled are now losing filling after 2 years.

The floor was installed 2 years ago ???
With all due respect...Why are these issues being brought up now? If it's a matter of some filler popping out of the end seams, it's as simple as re-filling. As far as the installer milling up the floor...Why is this? Something tells me we're not getting the entire picture here I'm still having problems understanding why this is brought up 2 years later ??

I agree with Howard, a little to late to do anything about. You accepted it two years ago.

Thanks again for your time. We (my wife) and I have been trying to get my concerns resolved with the person who installed the floor since it was installed in October 2008. We brought these concerns to his attention right after the install was finished with no success getting resolution. The list of issues is greater (1/16"+ gapping between rows when installed, milling defects still remaining after sanding, a hundred plus adjoining end joints within 2 to 4 inches of an end joint, minor damage to the house which I repaired, circular stain marks, raised wood grain after the water based poly was installed), however, I was curious about milling standards. Your original post suggests that an industry standard has not been developed, I suspect this might be a case as this probably is not an issue with milling typically near the specified board width. I work in the arboriculture trade and we only develop standards when issues/problems arise. Finally after nearly 2 years he has offered to take care of the problem, but wants more money. This person makes his own wood with his milling equipment, built a homemade kiln, and also installs floors. With what I know now about hardwood flooring manufacturing, I would run. If you had to speculate what is reasonable, what +- tolerance is acceptable for the wood width. I agree 5/16" variance between the widest and narrowest boards is huge. Is +-1/32 or less reasonable? I did find some posting for over wood tolerance with 0.02 or less reasonable for select or better and 0.03 for a lower grade. Using that as a guide, 1/50 would seem reasonable. Again, thank you for your time.

Sounds to me like the guy is making barn wood and trying to pass it off as high grade stuff. Buyer beware.