Barrel Reamers

The barrel reamer has a relatively flat face lined with rows of carbide cutters that allow the tool to cut and open the hole slightly larger than the diameter of its solid body. The reamer's cutting teeth overcut the tool body, allowing the slurry to flow past the reamer. Key features are: full diameter compaction; fixed conical carbide cutters for maximum performance and tool life; critical wear areas feature carbide hardsurfacing; replaceable fluid ports; special wear bars with carbide hardsurfacing to protect fluid ports.
The Barrel Reamer is a very useful tool:
Commonly used in bores where the formation types are relatively soft
Acts as a stabilizer when pulling larger reamers, fly cutters, or hole openers
Regularly used when installing final product
Shaft size: 3" – 5" 
Size range: 12" – 30"