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Ed Jones parabolizing - can anyone elaborate?

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#1 Lognic04

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Posted 16 April 2019 - 04:51 AM

Hi all,

For my 10 inch f3 mirror i have been starting to use the Ed jones method of parabolising. It took him approximately 2.5 hours to parabolise an 8 inch f3. I am using the technique he shows in his videos, 5 inch tool, and half half edge to edge strokes, and half elliptical/oval strokes. 

 

I have been working the long straight strokes more to more aggresively "hog" the center but it has hardly done anything over 30 mins of work. I have been working the ovals to cross the center at the closest, but not with the center, and at the furthest just kissing the left edge, so not a centered oval. Obviously this seems to be nowhere near as agressive as the method he is using, although i am trying to imitate it. Any input?

Thanks



#2 Ed Jones

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Posted 16 April 2019 - 08:01 AM

Logan,

  My method is right out of the "master"  Texereau's book page 97.  It's possible to spend too much time at the 70% zone and not much happens.  OTOH don't spend too much time in the center or you can dig a hole.



#3 Lognic04

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Posted 16 April 2019 - 08:25 AM

Hi Ed,

In your video you state you use oval strokes. Is that used with the texerau method? or is that on it's own as a specific method, sorry just a bit confised. the video in question is the 8 inch f3 mirror.



#4 Garyth64

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Posted 16 April 2019 - 08:42 AM

This page?

 

Texereau pg 97.jpg

 


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#5 Ed Jones

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Posted 16 April 2019 - 09:00 AM

Yes I round off my stroke just so I don't have the start stop that a W gives so it ends up being long oval when the spindle is turning, sometimes circular but not as a rule. 

 

Yes that's the page.


Edited by Ed Jones, 16 April 2019 - 09:24 AM.


#6 Ed Jones

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Posted 16 April 2019 - 09:37 AM

Texereau is assuming a fixed post but I use the spindle on my polisher.  I still make sort of a W but with ovals.  It is easy to dig a hole with a sub diameter lap.


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#7 Lognic04

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Posted 16 April 2019 - 05:17 PM

Thanks Ed. Sorry about the confusion, I'll give that a go today


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