[steve,gautam]
We tried to estimate what the load cell measurement should yield. Here is the weight breakdown (fudge factor for Al table is to try and account for tapped holes):
Element

Diameter [m]

Height [m]

Density [kg/m^3]

Mass [kg]

Number or fudge factor

Dim in inches

Table 
1.22 
0.08 
2700.00 
240.07 
0.85 
Dia=48", thickness=3" 
Stack leg 
0.36 
0.13 
8000.00 
100.85 
9 
Dia=14", thickness=5" 
Base plate 
1.37 
0.05 
8000.00 
600.18 
1 
Dia=60",thickness=2" 
Base rods 
0.10 
1.83 
8000.00 
118.55 
2 
Dia=4", length=6ft 
Stuff on table 



100.00 


Blue beams 



100.00 









Total [kg] 



2149.01 


Total [lbs] 



4835.28 


 Steve pointed out that there is some material removed from the stack legs for stability (hollows into which the viton springs fit). These countersinks have dimensions of diameter=2", height=1.75". So if we assume each leg has 10% less mass, the total weight becomes ~4600lbs.
 I think we will need to use one more load cell (i.e. total 4) for this measurement (we have more load cells, just need to setup one more controller).
 Steve is looking into acquiring some low profile jacks to deal with the fact that we only have limited travel range on the overall stack height because of the bellows.
 A useful document, from which we pulled some numbers (which also look reasonable using estimated dimensions and density calculations): P952005
