From: JOHN PHILO <JOHN.PHILO@amgen.com>
  To  : rasmb <rasmb@bbri.eri.harvard.edu>
  Date: 25 Jul 1995 12:39:03 U

Re: finding the right cells

        Reply to:   RE>>finding the right cells...

In reply to Jack Correia's response:
(a.k.a. here come the 'yes...buts')

I agree that the external loading cells everyone uses come 
from the Yphantis design, and most were made by his lab.  
That is exactly the point:  an essential piece of equipment has 
never been available from Beckman, but should be.

Yes, it is possible for a good machinist to make them, but:
(1) not everyone has access to a good machine shop willing 
to do small jobs and familiar with working with filled plastics; 
(2) in addition to the cells themselves, you really need tools 
and jigs made for polishing the sealing surfaces;
(3) even with jigs everyone says polishing is not 
straightforward, and the glass plates they use in Storrs for 
this purpose are not something the rest of us have.  
(4) Beckman itself has had trouble consistently polishing 
the standard 6-channel cells.

Yes, one could use velocity cells, but getting only 3 samples
per run is a serious limitation.  (I suppose conspiracy lovers  
could assume Beckman does not make the external loaders 
in order to sell more of the new 8 hole rotors.)

Yes, those of us with connections to UConn can probably 
prevail upon them to make some cells for us.  Should we 
have to?

Remember Jeff Hansen's vision of a new generation of 
users to go with a new generation of instrumentation!  
Are we really going to break the image of AU as a difficult, 
highly specialized tool only used by an in-crowd, and 
encourage its routine use by new users who don't want 
to make it a career, if they have to make their own cells 
or beg from the old-timers to get them?  I think not.

John Philo, Amgen