[3DEM] 626 cryoholder pin

[Bill Tivol]

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On May 1, 2006, at 9:56 PM, Melissa Jurica wrote:

> Just wanted to relate this experience: I have sheared the pin on a 626 
> cryoholder just by turning the holder the wrong direction.  One can 
> easily put significant torque on it due to the extra leverage afforded 
> by the mass of the holder.  Given my weak arm and my usually good 
> sense to never turn something that feels like it just doesn't want to 
> go, I was horrified to find I had made this mistake.  We were also 
> lucky that it didn't damage the scope, but it was a pretty penny to 
> fix the holder.
>
Hi Melissa,
	I am pretty sure that at the time the first pin broke the holder was 
not rotated in the wrong direction, and the second time it was in the 
pumping station just before it broke, so it was not rotated at all when 
it broke.  The large number of replies from people having similar 
experiences leads me to believe that user error plays a smaller role in 
this problem than design features.  I would be interested to find out 
the effect of thermal cycling on the material constituting the pin.
Yours,
Bill Tivol, PhD
EM Scientist and Manager
Cryo-Electron Microscopy Facility
Broad Center, Mail Code 114-96
California Institute of Technology
Pasadena CA 91125
(626) 395-8833
tivol at caltech.edu


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