Abrasive tool having a particular porosity variation

A large diameter abrasive wheel comprising:

• a body having an aspect ratio defined as a ratio between diameter to thickness of at least about 10:1, wherein the body includes:
• a first abrasive portion and a second abrasive portion distinct from the first abrasive portion, each of the first and second abrasive portions having abrasive grains contained within a matrix material comprising phenolic resin, wherein each of the first and second abrasive portions comprises at least about 40 vol % of abrasive grains, at least about 30 vol % matrix material and a mean porosity of at least about 5 vol % and not greater than about 30 vol %, wherein the mean porosity of each of the first and second abrasive portions is an average total porosity for a total volume of each of the first and second abrasive portions;
• and
• a first reinforcing member comprising glass-fiber and in the form of a layer distinct from the first and second abrasive portions and contained within the body, wherein the first reinforcing member includes a first planar face with a first major surface and a second planar face with a second major surface, the second major surface being parallel to and spaced apart from the first major surface, wherein the first abrasive portion overlies and is in direct contact with the first major surface of the first reinforcing member at a first interface extending through a diameter of the body, and wherein the second abrasive portion overlies and is in direct contact with the second major surface of the first reinforcing member at a second interface extending through a diameter of the body;
• and
• wherein the body comprises a porosity variation difference through at least half of a thickness of the body of not greater than 250% from a mean porosity of the body.