Our Fast Spiral Reamers feature a tight spiral that is very aggressive as well as a stop collar that stops the reamer when it has gone all the way through a hole. They are made from Hi-Tungsten tool steel, have a black and gold coating for maximum lubricity, and feature a 1/2" reduced shank with machined flats on it so they can be used in standard drills without slippage. They are designed to enlargen holes in structural steel plates found in truck frames, rail cars, bridges, and pressure vessels. Made in the USA by Norseman Drill & Tool.