what are those parts?

Hello Reprapers!

I have a rather silly question: where do you use the parts from the attached picture?
I got exactly two of them together with "parts for prusa mendel it.2". The "how to build" does not mention them.

Its easy to figure out, that standard 608 bearings go nicely into the top.
First I thought this is supposed to be some kind of plastic roll holder, but...

Anyway, I went through the web and could not get the answer.
Did any of you come across those parts?
Please direct me somewhere.

Best,
Pawel

Edited 2 time(s). Last edit at 09/16/2012 10:08AM by jedynywiking.

Looks like this one [www.thingiverse.com]

I'd recommend against using those, the idea is that they hold the z threaded rods straight, but in fact you want the z rods to wobble around unconstrained, while the x-axis is rigidly held by the z smooth rods. I just ended up with a load more z wobble when I installed mine.

Thank you guys for such a quick link and useful tips!

Following James advice, I will not be using them according to their purpose. On the other hand, it would be a waste not to use them

I am thinking about "plastic spool holder". Any other inventive ideas ?

Don't use them realy bad invention

Charlie

By all means re-use the bearings for a spool holder but don't use them on the z-axis.