Roller Reamer (Rotary reamer/roller stabilizer/ drilling reamer) is designed for various reaming stabilization in drilling operation. Especially it can perform the double functions of centralization and reaming when drilling in very abrasive formations. This is a versatile tool which can be used for different hole sizes ranging from 4-5/8" to 36" by selecting proper rollers and simply adjust the blocks. In addition, its service life can be extended by replacing new rollers when the old rollers are worn and become smaller.