The first pen holder didn't work well AT ALL.
It wobbled way too much, and if you presses the pen at
even a TINY angle, it jammed. So it was on to a better

I had two of these tiny linear slides, but they were all boogered up

You can see that they are missing most of their balls

(20 minutes later...)
But I took balls out of one and added them to the other to make
one complete unit

(20 minutes later...)
Then when you start to add the slide, all the balls fall out again.

(20 minutes later...)
You need to stuff balls down here when they start to all roll forward

FINALLY, I'm at the last two balls.

This is the new pen holder. I hope to try it out on Sunday