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How Do I Adjust the Tension on my Explore Scientific Telescope Crayford Focuser?


You can change the tension of the eyepiece holder. Just screw the tension knob (1) until you have the preferred focus knob tension. By turning the screw (2) clockwise, it will disengage the focus knobs, and lock the drawtube into position.   If you wish to further change the tension, you can adjust the two sets of three screws on the focuser's top side. The center silver hex screws hold a semicircular plate with four bearings that press on the draw tube. If you loosen the center screws (and the tension control screw), you can adjust the four black hex screws to provide the desired pressure. You need do this is very small increments ¨C too tight and the draw tube will focus roughly and too loose the focuser will not hold position well. After adjustment the center screws should be retightened and tightening the tension control screw will be more aggressive.  Here is a video about adjusting the focuser also: