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Entry  Mon Jul 9 17:29:28 2018, Udit Khandelwal, Summary, Tip-TIlt, TipTilt mirror holder final changes d_COM.png1-1.png1-2.png2-1.png
    Reply  Tue Mar 5 15:56:27 2019, gautam, Summary, Tip-TIlt, Discussion points about TT re-design 
Message ID: 14047     Entry time: Mon Jul 9 17:29:28 2018     Reply to this: 14474
Author: Udit Khandelwal 
Type: Summary 
Category: Tip-TIlt 
Subject: TipTilt mirror holder final changes 

Final Summary of changes to mirror holder in Tip-Tilt holder.

Determining minimum range for Side Clamp:

1. The initial distance b/w wire-release point and mirror assembly COM = 0.265 mm


2. But this distance is assuming that wire-release point is at mid-point of clamp. So I'm settling on a range of +/- 1mm. The screenshots below confirm range of ~1mm between (1) side screw & protrusion and (2) clamp screw and clamp.

Determining length of tilt-weight assembly rod at the bottom to get \pm 20mRad range

The tilt-weight assembly is made from following Mcmaster parts:
Rod   - 95412A864 18-8 SS  #2-56 Threaded Rod
Nuts  - 91855A103 18-8 SS #2-56 Acorn Cap Nut

Since the weights are fixed, only rod length can be changed to get the angle range.

tan \theta =\frac{d}{h}

d= h \times tan\theta = 34.25\text{mm} \times tan(20 \text{mRad}) = 0.69 \text{mm}
So a range of 1 mm between nut's inner face and mirror-holder face should be enough. Since holder is 12 mm thick, rod length = 12mm + 2 x 1mm + 2 x (nut length) = 12 + 2 + 9.6 = 23.6 mm = 0.93 inch. So a 1" rod from Mcmaster will be fine.

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