[HAM] How to Rethread a Scanner without drilling

[David Anderson]

On Jun 18, 2008, at 12:45 PM, Jim Shanks wrote:

> I tried for more than an hour to get anything around that bearing.   
> It's
> in there very tight.  On the motors it's easy, but in the scanner, the
> string goes through a very small hole, and the hole is behind the flat
> spring metal.  If you know a method to get the string in there, I'd be
> interested to know how.


Ask, and you shall receive (I wrote this up for future reference  
after doing it once):

How to rethread a scanner bearing.

Tools/Parts needed:

Strong thread (button thread works)
Scissors
Some very small gauge wire/inside of a garbage bag twist-tie
Hemostats or needle-nosed pliers
Magnifying glass, depending on your vision
Good light

1)    Remove all the old thread. Often the loop around the bearing is  
intact, so you have to carefully cut the old thread with the end of a  
razor knife or some other such implement. I found that sharpening the  
end of a paper clip worked well. Don’t pull too hard when removing it  
since it can catch between the bearing and the flat springs.

2)    Push the new thread in through the outside hole in the bearing.  
On the bearing closest to the motor, this will be on the motor side.

3)    When you can see the thread between two of the copper-colored  
springs that hold the bearing in place, use the small gauge wire to  
fish it up between the springs till you can grab it with the hemostats.

4)    Pull a generous length of thread through.

5)    Leaving a large loop that you will use at the end to tie the  
knot, push the thread back through the gap you just fished it out of  
and towards the next gap. When you can see it, fish it up through the  
second gap, but make sure you leave the loop at the first gap.

6)    Repeat the process till you’re back at the first gap, at which  
point there will be three sections of thread passing through that  
gap: the two ends of the loop around the bearing and the thread that  
will bring the oil into the bearing.

7)    Make sure the thread is seated in the groove in the bearing.

8)    Tie a square knot to hold the thread as tightly as you can  
around the bearing without breaking the thread.

9)    Cut the excess thread from the free end.

10) Pull the leftover loop back through the bearing and tug gently to  
move the knot under the spring.

11) Cut the thread at the spool end leaving a generous amount to  
reach the oiling cup and wrap around the oil felt.