Measurement science is its own language. These few notes barely scratch the surface. If you are new to this, or will just be peripherally involved, perhaps as a sales support person, it is suggested that you learn decimal equivalents down to the sixteenths, and key metric sizes, such as 5mm, 10mm, 20mm, 50mm, etc. It will make your life a lot easier.
15/16″ is fifteen sixteenths. Not fifteen sixteens.
.010″ is ten thousandths, .003″ is three thousandths, .0005″ is; half a tenth, or five ten thousandths.
In all methods of measurement tolerances nothing is an absolute single number. Tolerances are represented in a range. It is important to both parties involved in a transaction understand what that range involves. If you are not sure, ask. It may vary from company to company, product to prodcut, or even from material to material. In the case of machine tolerances, the spread may be just a few thousandths. Bar length ranges may involve many feet.
The above is not intended to be all-inclusive but a random exposure to the topic. We will try to broaden the scope in future posts.