5 tube balancing argument

[Dima Klenchin]

In article <325D9AD9.32DE at GENVEC.COM>,
   CANTOLUPO at GENVEC.COM (Lou Cantolupo) wrote:
->Well, I took it upon myself to call the centrifuge experts, Beckman. 

Wow, what a rigor!


->HOWEVER.  In an ultra centrifuge, where you routinely approach speeds in
->excess of 80,000 rpm (as in CsCl grad's), it is imperetive that you fill
->all slots with equal weights.  In ultra, where the rotor tolerance is
->5/10,000 of an inch in the eliptical orbit, equal vector forces prove
->not to be so equal unless they are 100% equal.  In otherwords, when you
->go fast, the rules can't be bent as easily; you have to optimize your
->orbit.  

Yep. That's exactly why for [ultras AND big rotors] it is highly 
recommended that one always fills all positions with ~ equal weights. Yes, 
this can be irritating on a 8-positions when all you need is a single 
gradient, but good care of ultracentrifuge and - particularly - rotor 
implies just that. 

Off to for a spin, 

- Dima