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Entry  Thu Nov 1 17:37:00 2012, Steve, Update, General, bronze bushing for 40m vac IMG_1764.JPG
    Reply  Fri Nov 2 03:28:54 2012, rana, Update, General, bronze bushing for 40m vac 
       Reply  Fri Nov 2 14:37:36 2012, Jenne, Update, General, Open-sided mount - why 
          Reply  Fri Nov 2 16:09:14 2012, Steve, Update, General, Open-sided mount - why 
Message ID: 7663     Entry time: Fri Nov 2 16:09:14 2012     In reply to: 7662
Author: Steve 
Type: Update 
Category: General 
Subject: Open-sided mount - why 




Suprema- SS clear edge mirror mount 2" diameter is modified for 40m vacuum use. One left and one right handed one. It's adjustment screw housing is bronze! It is not ideal for out gassing.

It will be baked and scanned. If it passes we should use it.

We may need these to bring out some pick-off beams.

 I vote against it. We don't know about the grease inside the screw bushings - scans are not everything if adjusting the screw loosens up the grease. If we need more pick off mirrors lets just make some of the kind that we already use inside for the 2" optics.

 I think Steve had these prepared in response to my question a few days ago of how badly do we need adjustability for the POX/POY mirrors?  We already have cleaned open-sided mounts that have no adjustment screws.  So as long as the beam reflects off the ITMs horizontally (which it should), we can do yaw adjustment by twisting the whole mount. We don't need super fine yaw adjustment, we just need to get the beam out, so this is probably good enough.

We should put the POY mirror on this open-sided mount (the one without screws) some time.  Perhaps even today.

 The hex adjustment screw  is removed from the brass bushing for degreasing, cleaning and baking. Newport says the  bushing is is brass not bronze.

Brass outgassing rate is 10x higher than copper that is truth. The surface area is small so  Krytox grease is ok if it is really needed in the 40m. ( It was ok in the past and it is still there )

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