I often read that someone with a backlash problem says they tightened everything. When asked if they checked the set screws, they say, “yeah, those are tight too.”
Sometimes they can feel tight when actually they are not. In the illustration below, the “B” image illustrates the proper position of the set screw in relation to the flat area on the shaft. Of course you cannot see this, so how are you supposed to know if yours is correct?
If you try to tighten the screw in the “A” image, you will not tighten it more because it is already sitting on the shaft. You will think it is tight, but obviously it is not. What to do?
- Loosen the set screw slightly.
- Twist the shaft or collar|pulley back and forth.
- If it moves, then it was not in the proper place.
- Hold the shaft and rock the collar|pulley back and forth using the Allen wrench as a lever.
- Slightly and gently tighten the set screw while rocking back and forth.
- Once you reach a point where you can no longer tighten the set screw, you have reached the position in the “B” image.
- Lock the set screw down.
- Test for backlash.
