The primary parabolic mirror of H1 TMSX turned out to be about 80 to 100 thousandth of an inch thinner than in the DCC drawing (https://dcc.ligo.org/LIGO-D1000075).

The thickness at the thinnest and the thickest edge were measured to be [1.608", 2.868"] VS [1.69, 2.97] in the DCC drawing.

The specification (https://dcc.ligo.org/LIGO-E0900347) states that it should be 43+-1mm or 1.693+-0.039" at the thinnest edge.

OTOH, the manufacturer certificate of compliance (https://dcc.ligo.org/LIGO-E1300278) states that the spec is 41+-1mm or 1.614+-0.039", presumably at the thinnest edge, that's about 80 thousands right there. Either the mfg or the spec document is wrong.

Either way, the consequence is that the mirror thickness as of now is outside of the adjustment range of clamps, and the clamps don't touch the optic at all. 

Bottom two clamps: You can easily insert a 25 thou metal between the mirror and the bottom clamps (picture), but I couldn't slip 50 thou washer.

Top clamp: I didn't want to risk dropping a metal piece on the center of the optic, so I didn't slip anything to the top. However, the top thickness is 1.608", and the clamp is designed to accomodate 1.68" or thicker optic, so it seems as if there is a 70 thou-ish gap.

After a conversation with Ken Mailand, I decided to re-machine the clamp locally to shave off 100 thousandth from the top of the clamp standoff. Hopefully Tylor can do it by the end of Thursday and Justin can slip them in the next oven load.