I don't see how the loose bearings can do ANYTHING for balance, since they will be forced to race around the track by the rotation of the shaft, and given any size difference between shaft and bearing {ie 1:1 rotation) can't possibly stay in position to 'balance' anything, or for that matter move to where they could create any balancing effect. I would suggest it was just poor quality control, or by design (save money by using minimum needed). Robert On Thu, Mar 5, 2015 at 12:17 PM, Robert Dvoracek wro= te: > Sorry, Microsoft munged that video link. > > http://youtu.be/eq263AYgyYg > > ---------------------------------------- >> From: lgtngstk@hotmail.com >> To: piclist@mit.edu >> Subject: RE: [OT]: CD/DVD spindle boss has free moving bearings >> Date: Thu, 5 Mar 2015 14:15:35 -0500 >> >> Yes, they are for automatic balancing. >> >> https://www.youtube.com/watch?v=3Deq263AYgy= Yg >> >> ---------------------------------------- >>> Date: Fri, 6 Mar 2015 01:12:36 +0800 >>> Subject: [OT]: CD/DVD spindle boss has free moving bearings >>> From: justin.richards@gmail.com >>> To: piclist@mit.edu >>> >>> I have noticed that CD/DVD drives make noises when starting/stopping. >>> >>> I had assumed it was simply motor noise but never quite satisfied with = that. >>> >>> I have just dismantled the spindle boss(the bit the disk sits on then h= as >>> the magnetic clamp to hold in place) and discovered there are about 10 >>> small bearing that are free to move about in a race and the source of t= he >>> noise. >>> >>> I can only guess they are for balance. >>> >>> Anyone know how they work and if they are for balancing. >>> >>> Justin >>> -- >>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>> View/change your membership options at >>> http://mailman.mit.edu/mailman/listinfo/piclist >> > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .