before or after positioning the covers sections about the drill collar the first cover section is also threaded onto the drill collar at threaded connection 344 the cover sections may then be rotated relative to the drill collar 302 to tighten the threaded connection 344 and secure the cover sections in place preferably the covers are securably positioned to preload the cover sections and reduce or eliminate relative motion between the cover sections and the tool body 302 during drilling the cover 342 may be removed from drill collar 302 to access the sample chambers for example the cover 342 may be rotated to un mate the threaded connection 344 to allow access to the sample chamber the cover 342 may be provided with one or more windows 346 window 346 of the cover 342 may be used to access the sample chamber 314 the window may be used to access valves 330 a 330 b on the sample chamber 314 window 346 permits the manual valve 330 a to be accessed at the surface without the need for removing the cover 342 also it will be appreciated by those skilled in that art that a windowed cover may be bolted or otherwise operatively connected to the tool body 302 instead of being threadably engaged thereto one or more such windows and or covers may be provided about the drill collar to selectively provide access and or to secure the sample chamber in the drill collar the sample chamber is preferably removably supported in the drill collar the sample chamber is supported at an end.