Viewports

20/01/08

I had a couple of options for this conical shape.  The angle is 45 degrees, so I could have measured the 5.25 inch OD of the bevel and gone in at the correct angle.  However, I turned down the inside diameter of the bore first to the correct 3.25 inches to give me something to aim at.  Then I started with the 45 degree angle.  I set the machine  up as accurately as I could, but I then used these Vernier protractors to measure the angle exactly.  These things are very accurate and on each pass, I was able to adjust the machine in very small increments until this angle was exactly 45 degrees.  I needed it to be perfect because the lens should fit flush to the bevel. 

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