When preparing a shaft for CSL, may I use access tubes of different diameters in the same shaft?


Yes, provided they are all larger than 38 mm (1.5 inches) internal diameter. The Cross-Hole Analyzer (CHAMP) and the CHA-W software both allow entering the individual tube diameters. However, the probes should be used with “centralizers” to keep the probes in the center of the tubes, and this may create some difficulty if the tubes are not the same lengths and have the same bottom of tube elevation.