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Entry  Fri Feb 19 15:17:51 2021, Jordan, Update, SUS, CoM Range on 3"->2" Adapter Ring for SOS Neutral_Point.pngDumbell_Max_Negative_Travel.pngDumbell_Max_Positive_Travel.png
    Reply  Fri Feb 19 16:06:01 2021, Koji, Update, SUS, CoM Range on 3"->2" Adapter Ring for SOS 
       Reply  Fri Feb 19 16:14:16 2021, gautam, Update, SUS, CoM Range on 3"->2" Adapter Ring for SOS 
          Reply  Fri Feb 19 16:55:26 2021, Koji, Update, SUS, CoM Range on 3"->2" Adapter Ring for SOS 
Message ID: 15826     Entry time: Fri Feb 19 16:55:26 2021     In reply to: 15825
Author: Koji 
Type: Update 
Category: SUS 
Subject: CoM Range on 3"->2" Adapter Ring for SOS 

Jordan's screenshot actually shows that the vertical distance (Y) is 0.0000". We want to have the vertical distance of CoM from the wire clamping point to be 0.9mm in the nominal SOS design (this might need to be adjusted to have a similar pitch resonant freq for the different inertia of moment). Let's say it is ~mm ish.

The full range of the bottom dumbbell adjustment gives us the CoM adjustment range of +/-0.002” = +/-50um. This corresponds to an alignment range of +/-50mrad. And we want to set it within +/-500urad.
So we need to adjust the dumbbell position with the precision of 1/100 of the full range (precision of 0.5um).

The groove does not extend to the top of the clamp. The groove shallower than the wire diameter cause the hysteresis of the alignment. Also, the material of the pieces should be stainless steel. Al clamp is softer than the wire and will cause the groove to be dug on the material, causing increased bending friction and hysteresis again.

Saying, all of our suspended masses with Al stand-offs are suffering this issue to some extent. That was the reason to buy the ruby standoffs.

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