My primary imaging telescope is an 8" (203mm) f/4.9 Orion (USA) reflector, actually made in China by Synta. I purchased this telescope just before Orion switched to a Crayford style focuser - mine has the old rack and pinion focuser, which has been the only major complaint I have had about the telescope. The first adjustment I learned to perform on this focuser was the draw-tube tension adjustment.

On the bottom of the focuser is a rectangular plate held in place with four phillips head screws (photo A). Beneath this plate is the pinion gear (photo B), which is cut into the shaft that the two focus knobs turn. Over the pinion gear is a spring clip (photo C) that presses down on the shaft to create tension. If you remove the cover plate, be careful of the spring clip. It does not have enough tension to pop off when you remove the plate, but it could fall off. Note the orientation of the spring clip so you can put it back in the same position.

There is a small amount of grease on the pinion gear and the rack below it. If dirt collects here, you will need to disassemble the focuser and clean it. A good grease designed for low temperature compatibility, such as a grease made for screw-type garage door openers, should be applied sparingly to the pinion and rack after the cleaning.

The draw-tube tension needs to be enough so that the weight of a camera or heavy eyepiece doesn't move the focuser. It should not, however, stick or be hard to turn. The tension is adjusted by loosening or tightening the four phillips head screws, pressing the cover plate down and compressing the spring clip.

After adjusting the draw-tube tension, my focuser action is fairly smooth, with ample tension to hold my camera without slipping, but not difficult to turn.