Well said ther Jon!
I agree with Tim also, and would just like to add that "fittings out of a box' will certainly have some distinct variations in their specific dimensions, bevel/land shapes & configurations or even chemical compositions depending on the supplier, and depending on their country of origin, the accuracy of the fittings dimensions within their listed tolerances will vary greatly!!!
Why is this something to look out for? Well. both Jon & Tim work to certain codes that would reject some of these fittings because of the discrepancies found that do not conform within the specifications listed for certain codes or standards even though some of the fittings may have the standards stamped on the fittings as to say that they are in compliance but, when scrutinized further - they are found not be in compliance. This is why inspection upon delivery of these items must be done at shops that manufacture components that are to be delivered to the Customer/Client who demands such exacting specifications as per contract docs.
Case in point; 1.) Hi-low conditions are constistently occurring when using company "X" fittings but, no such conditions are the norm when using "Y' company's fittings, and the work required, loss of time, added labor costs do not justify the continued use of the fittings being supplied by "X" company especially if the pricing between the two companies are so close that to continue using "X" company's fittings would end up almost eliminating our margins!
2.) Some fittings were delivered with chemical compositions very different than what their MTR's had listed or what their stampings represented, and Jon has probably ran into this from time to time with the type of work he's involved with so, if you want to add your own experience - please do Jon!
3.) O.D.'s/I.D.'s & wall thicknesses vary on pipe & tubing coming from different countries so. it's important to have reference books available to you so that you can cross reference from let's say UNS numbers, DIN numbers or even JIS number equivalents because of the slight differences in these dimensions.
There are other discrepencies to look out for but for now, I'll just point out the more prevelant ones.
I know for sure that many of us have found more than once, some fittings that just were'nt acceptable, yet when questioned as to why we would'nt accept them - were told otherwise by the vendors, and ultimately had to make the call to reject those fittings & use alternative suppliers that would indeed meet specs.
Hope I did'nt open up another can of worms here.
Respectfully,
Henry