Airpads Measurements and Damage Assessment

John Monnier, April 2001

In anticipation of sending 4 pads to Specialty Components, a careful assessment of all existing pads was performed. I will now report on the results.

For each pad, the following test were done:

1. They were checked for air Leaks (Yes/NO)
2. They were checked for vibrations (Yes/No/Small) by supplying pad with air and pushing down on a smooth granite surface.
3. All 10 pads were ranked based on visual inspection by JDMonnier, EPedretti, and Marc Lacasse independently.
4. A collective rank was assigned based on average rank [in the final assessment, a few deep grooves were considered worse than many shallow grooves]

                                  Ranks [1=best, 10=worst]
 
ID# (prev.loc)  Leak?  Vibrate? JDM  EP   ML  Collective
*00002 (2S) No Yes 9 10 9 10
*A0110 (1T) No  No  10 5 10 9
*A0111 (1T) No     Yes 7 6 8 8
00004 (1S) No No 6 8 5 6/7
 00005 (1S)  No No 5 7 7 6/7
*A0109 (2T) No Small 8 4 6 5
00003 (2S)  No No 4 9 3 4
IOTA1 (2T)   No No 3 3 4 3
A0119 (1BIG)     No No 2 1 2 2
IOTA2 (2BIG)  No No 1 2 1 1

 [key for prev(ious).loc.(ation): (delay line #)(S=Side, T=Top, B=BIGtop)]
[Recall Table 1 was the problematic one]

As you can see there was a fair amount of agreement between the 3 judges, and that 4 of the 5 worst pads were on Table 1, including one badly vibrating top pad.

The asterisked-pads above are the ones we are sending for refurbishment based on the following 3 criteria:
1) If the pad vibrated on the granite block, then refurbishment was considered necessary.
2) Few deep grooves were considered worse than many light grooves
3) A0110 was on Table 1 which was giving us so much trouble, and so broke the tie for 4th place.
 

I also suggest that Pads 00004, 00005 and 00003 are replaced with the nice spares for next run since they are quite scratched, but nothing too deep. [please inspect for yourself]

Airpads Inventory -- Description and History

Airpad Info

Table 1:  old table (NORTH)
Table 2:  new table (SOUTH)

e.g, Location 1T: table 1 on TOP    [ BIG == the big one on top ]
       Location 2S: table 2 on SIDE

ID      Location        Description /
#       Date, Table #   Condition

A0119   2001Mar, 1BIG   2 stubs one, 2 on the other, 2 on side
                        Many scratches -- much worse than the other
                        Grade A/B

A0110   2001Mar, 1T     Two stubs on each end
                        Long grooves on surface -- deep
                        mostly near one edge
                        Grade: D

A0111   2001Mar, 1T     Two stubs on each end
                        long grooves on surface -- deep
                        but not too many..
                        mostly near one edge
                        Grade: C

00005   2001Mar, 1S     4 stubs on one end, 2 the other
                        light longitudinal scratches
                        looks more beat up, dings, dents
                        Grade: C

00004   2001Mar, 1S     4 stubs on one end, 2 the other
                        light longitudinal scratches
                        and some transverse scratching
                        beat up w/ dings, dents
                        Grade: C

-------

IOTA2   2001Mar, 2BIG   4 stubs one end, 2 the other
                        Light scratches, some air ports are
                        red.
                        Grade: A

A0109   2001Mar, 2T     Two stubs on each end
                        Lots of light long scratches
                        Grade:  B/C

IOTA1   2001Mar, 2T     Two stubs on each end
                        Mostly nice surface, only a few
                        longitudinal scratches
                        I think this is a new one
                        Grade: A

00003   2001Mar, 2S     4 stubs on one end, 2 the other
                        longitudinal scratches
                        Grade: C

00002   2001Mar, 2S     4 stubs on one end, 2 the other
                        longitudinal scratches -- deeper
                        Grade: D

--------

IOTA3   2001Mar, SPARE  4 holes on each end
[00004]                 no stubs in place and not set screws
                        Perfect shape -- brand new
                        Grade: A+

00001   2001Mar, SPARE  4 holes on each end
                        no stubs in place and not set screws
                        Perfect shape -- brand new
                        Grade: A+

IOTA4   2001Mar, SPARE  2 holes on one end, 4 the other
[00001]                 ALL filled with set screws.
                        Great Shape.. Came with small chart of
                        displacement vs. load: 80psi,80lb ok
                        Grade: A+

IOTA5   2000Dec, LD2    Removed
[00002] 2002Dec, SPARE  Polished by WT to 9 fringes,
                        0.11/1000" P-P
                        Visually looks great.
                        2 holes one side, 4 the other
                        missing all stubs and set screws.
                        Grade: A

IOTA6   2000, LD1       Removed by CP and polished at Harvard
        ::CP has it     failed -- vibrated excessively
                        CP still has this one
-not labeled
 

AIRPAD Parts:   We have a box of stubs, set screws, and air-line connectors.



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