A checking and focusing device for an telescope eyepiece includes an
eyepiece barrel formed of an inner tube and an outer tube. The outer tube
has at one end a clamping portion formed with multiple resilient segments
in a radial shape. A locking ring is threaded onto the clamping portion
so that rotating the locking ring can gradually constrict the resilient
segments to clamp the eyepiece tightly without biasing its axis. A
production process for the chucking and focusing device for an telescope
eyepiece includes two steps. One step is to machine multiple lengthwise
grooves in an inner surface of a metal tube, the thickness of the grooves
being the same as the depth of the resilient segments. The tube is then
machined until the grooves are exposed, forming a single elastic strip
between every two grooves, forming the clamping portion of the tube.