[RASMB] (no subject)

Leech, AP apl3 at york.ac.uk
Wed May 13 10:48:28 PDT 2009


Hello Keith,

How are you cleaning and keeping your screw rings and housings?
I find a sort of grey gritty stuff tends to accumulate in the
threads and needs cleaning out every so often. I had assumed this
was the reason for lubricating with spincote. The housings and
screw rings are made of aluminium (aluminum in the States!) and
are rather liable to corrosion from salt solutions, so I only
ever clean with water and ethanol, and keep them dry.

The metal is also rather soft - I believe this helps in distributing
stress at high g. However it also means using too much brute force
can deform the housing. We have a couple that have evidently suffered
this way and they don't give good data, so I keep them only for "show
and tell" sessions.

Gentle methods of freeing things up could be temperature cycling
(freezer) or sonication. If you have to sacrifice the housing and
screw ring, probably very careful work with a hacksaw is your best
bet!

Regards to all,

Andrew

Connaghan, Keith D wrote:
> Hello,
> 
>  
> 
> Recently a screw ring became stuck in a velocity housing used with our 
> XL-A. This is the second time this has happened in the last few months. 
> It appears that the screw ring becomes miss-threaded, one time after a 
> 50,000rpm run, and a second during cell assembly prior to a run. In both 
> instances the screw ring was threaded properly, gently tightened and 
> loosened several times to further ensure proper threading, then at some 
> point seizes such that the torque wrench and stand cannot loosen the 
> cell assembly. (Our practice for assembling cells does not include Spin 
> Coat due to the issues I have had with contamination of the windows and 
> such.)
> 
>  
> 
> That being said I have two questions. First, am I correct in thinking 
> that the seizing of the screw ring is likely due to deformation of the 
> cell housing? Second, we were able to use sturdier tools (compared to 
> the torque wrench and stand) to separate the screw ring and housing in 
> the first instance of this issue. However, no such luck in the second 
> occurrence, does anyone have any suggestions for recovering at least the 
> windows if not the windows and the centerpiece from the housing?
> 
>  
> 
> Thank you in advance,
> 
> Keith Connaghan
> 
>  
> 
> /*/Please note my email address is now /*/keith.connaghan at ucdenver.edu 
> <mailto:keith.connaghan at ucdenver.edu>
> 
> -----------------------------------------------------------------------
> 
> //Keith D. Connaghan//
> 
> //University//// of Colorado Denver//
> 
> //Anschutz Med. Campus//
> 
> //Dept. of Pharm. Sciences//
> 
> //RC-2, Rm. 4450A, Mail Stop C238-P15//
> 
> //(303)724-6119//
> 
>  
> 
>  
> 
>  
> 
>  
> 
> 
> ------------------------------------------------------------------------
> 
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-- 
Dr Andrew Leech                   *  Laboratory Head
Technology Facility               *  Molecular Interactions Laboratory
Department of Biology (Area 15)   *  Tel   : +44 (0)1904 328723
University of York                *  Fax   : +44 (0)1904 328804
PO Box 373,  York  YO10 5YW       *  Email : apl3 at york.ac.uk



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