Under reaming systems are the most economical solutions for casing drilling in normal ground conditions. This is particularly true for shallow holes, as is often the case in water well drilling. We have sizes 4", 5", 6" and 8" ODEX systems available.
The ODEX system utilizes an eccentric under reamer to cut a drilled hole ahead of the bottom of the casing. The casing is then simultaneously advanced by a percussive force applied to either the top or bottom of the casing. As the hole is advanced, the drill cuttings are normally removed by air and travel up the inside of the casing in the annular space between the casing ID and the drill rod OD. The ODEX method is highly effective in overburden soils where boulders or gravel layers are present, or when layers of rock must be penetrated. This method also subjects surficial and localized soils to some vibration.
Currently Odex is available from 3" to 8" DTH hammers.