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Re: [ATM] Figuring questions on a 6f6.
Hi Jerry and all,
Sorry, I should have included more background information.
1) I'm working in inches.
2) My source and knife edge move together ("Moving" in FigureXP).
3) Here is my mask configuration from Mark D. Holm's Couder Mask
software.
Main mask zones
Zone R inner R outer R center Rcenter
Method
0 0.915 1.886 1.442 Carlin
1 1.886 2.506 2.207 Carlin
2 2.506 3.000 2.758 Carlin
The secondary is 1.83 inches.
4) It looks like the decimal place is off on my Ideal Knife Edge numbers
below. Here are the corrected values:
1) 0.000
2) 0.019
3) 0.038
Thanks for looking at this stuff.
-Anthony
> -----Original Message-----
> From: Jerry [mailto:wa4guu@verizon.net]
> Sent: Tuesday, October 09, 2007 12:25 PM
> To: Anthony Anconetani; atm@atmlist.net
> Subject: RE: [ATM] Figuring questions on a 6f6.
>
> Hello Anthony
>
> Let's check the numbers first.
> Are those knife readings inches or mm?
> 1.9 and 3.8 mm look more like proper numbers for a fixed
> source tester.
> I haven't used FigureXP, I don't know if that does inches or not.
>
> .125" would be knife movement from center to edge with a
> fixed source tester. so with the center of the mask opening a
> little inside the edge about 1/4" .107" or 3.8mm would be
> right for a fixed source tester. So I think I know what you
> mean on the desired readings but then I don't know about the
> actual readings. Maybe those are inches. That looks matches
> better what I would expect 10 minutes of work to do. In that
> case your target numbers in inches would be .075 for zone 2
> and .107 for zone 3. Is your micrometer calibrated in inches or mm?
>
> You mask dimensions would be helpful.
> And what kind of tester do you have? Does the light source
> and knife mover together?
>
> Jerry
>
> -----Original Message-----
> From: atm-bounces@atmlist.net
> [mailto:atm-bounces@atmlist.net] On Behalf Of Anthony Anconetani
> Sent: Tuesday, October 09, 2007 10:19 AM
> To: atm@atmlist.net
> Subject: [ATM] Figuring questions on a 6f6.
>
> Good morning guys,
>
> Well, I'm trying to decide where to go next in figuring my 6F6 mirror.
> Before I do anything rash, I think I need to consult with the experts.
>
> The ideal measurements in FigureXP are
>
> 0.000
> 0.0019
> 0.0038
>
> The room temp is 85-87 degrees (still hot in Texas). The tool
> is full sized with G73.
>
>
> After about three hours of polishing I checked the figure.
> The edge looked good and the mirror looked spherical. I
> decided to do another hour of polishing to be safe. I then
> checked the figure again made the following measurements:
>
> 1: 0
> 2: -0.014
> 3: -0.023
>
> I decided I was high in the center but I knew that would be
> easy to fix.
> So decided to try some parabolizing.
>
> I did 10 minutes of MOT using the parabolizing stroke. I
> tried modified the stroke to do some extra work around Z2 and
> Z3. Here were the results.
>
> 1: 0
> 2: 0.043
> 3: 0.045
>
> I was a little surprised at how much I actually took out of
> the center.
> I'm guessing I went to far to the left and right. Anyway, I
> decided to go with a basic 1/3 COC TOT stroke. I figured this
> would reduce the correction between Z1 and Z2 and would
> reduce Z3. Ten minutes of 1/3 COC TOT gave the following.
>
> 1: 0.000
> 2: 0.036
> 3: 0.060
>
> I was happy with the reduction in correction from Z1 to Z2. I
> also noticed that Z1 had a smoother transition from it's
> inner edge to it's outer edge. However, I was really
> surprised to see the delta from Z1 to
> Z3 increase. I thought the TOT would have a tendency to
> flatten out the mirror. The above indicates the center became deeper.
>
> I mulled this over for a while and decided to try another
> round of 1/3 COC TOT. My guess was that Z3's increase
> relative to Z1 was a temporary dynamic in the glass. I think
> was wrong. Here are the results of 10 minutes 1/3 COC TOT:
>
> 1: 0.000
> 2: 0.053
> 3: 0.088
>
> Well, I'm thinking COC TOT is not a good idea at this point.
> I'm just really surprised that the center got deeper.
>
> So questions:
>
> 1) Why did COC TOT deepen the center?
>
> 2) Since COC TOT does not appear to be reducing the outer
> zone, how should I reduce the outer zone? A narrow W stroke
> with 1/2 diameter MOT?
> Or maybe a wide W stroke with 1/6 TOT? How about a stick of
> dynamite...
>
> Thanks,
>
> -Anthony, Round Rock TX.
>
>
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