Hi Mark,

Modeled with the 3 pads at 120 degrees at the 70ish percent of radius at the thickness of 0.055" constrained the secondary from a vertical orientation of the whole scope to a horizontal position to a movement of less than 0.00015 inches of laterial movement.

That with no movement of the secondary or backing plate due to thermal expansion and at that point we did not look at anything thinner.

Getting the 3 points to be the same size in diameter and the same thickness proved to be the biggest challange and it took many trials to develope a method to do just that.

Regards,

Preston