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Final Figuring Fun

Started by ZWAY2B, 07/23/2002 08:07AM
Posted 07/23/2002 08:07AM Opening Post
I redesigned my Foucault tester by using a Large bright green LED and this did make it much easier to judge the test results. I am using a 5 zone mask on a 10 inch mirror and because of the lack of eye relief I have a hard time seeing both windows at the same time on zones 4 and 5. So I have to adjust my eye position to make this determination. Is this going to skew my observations significantly?

I think I've made all the typical first time mistakes. I have a good smooth surface and I'm within about 1/2 wave right now but I,ve gone through many beginner mistakes to get to this point.

My progression is like this.

A. Central Hill with Raised ridge at 70% zone and slight TDE
B. Central Hill with Raised Ridge
C. Raised Ridge at 70 %
D. Poured new lap and temp in garge changed from 85 to 70 degrees. Now I have blown a large hole and have a depressed ridge at 70% (did this on the machine instead of hand)
E. Center zone and zone 1 blended together and hole removed.
F. Center zone and zones 4 and 5 all need reduced

This is where I am now. In addition I've seen and learned alot about surface defects. Pimples, Dimples, zones, etc.

Most all of the stroke info, lap masking, and eccentuated pressure have work exactly as advertised but one area that is not discussed in much detail but has a big effect in my experience is pitch hardness and flow. I was right on target to produce a nice parabola when I made a new lap and the temp changed which made the lap characteristics much harder. The lap still performed as expected based on the technique but the rate at which this change occured was an order aof magnitude greater. This change in flow increased the laps effectiveness significantly. I blew way past my intended target with a session about 1/2 the duration of the previous sessions. I was trying to be cautious because of the new lap but still was to aggressive. The temps are back to normal now and the lap is back to its original pace.
Slow and steady. I had a productive session last night and hope to test at lunch time.

The challenge just adds to the fun.

Dave H.
Posted 07/23/2002 11:23AM #1
Checked my last session results and see that I once again have misjudged the results. I don't need to deepen zones 1,4,&5 I need to increase the slope. What I did in trying to deepen the zone was flatten the slope which made it worse. This is process is not intuitively clear to me but all this visualization is helping. Thanks goodness you can go at it again, and again.

Dave H.