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  #381  
Old 06-08-2020, 11:33 AM
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Sunfish (Ray)
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Thanks for that.
I was directed to this site by the ATM who gave me the blanks and this blog describes working with a TDE .

http://atm-workshop.com/mirror14-log.html

Perhaps it is possible to be over corrected in the centre as per the stellafane table yet still have TDE. I did start off through the whole polish with short strokes But not much W . So I can try adding more W pattern stroke with the trimmed up lap.

I have an 8 inch to go on to which is down to f7 which I would like to deepen to f4 with a tile tool and 80 grit.

Quote:
Originally Posted by Spacecat View Post
Sunfish - the best strokes to get rid of TDE are very short 1/4 to 1/5 length W stroke with mirror face up , with some randomness thrown in to maintain or head better toward spherical .


Something like a 200mm mirror is much better fit for the hands and more stable , so you are setting yourself a task with a 100mm . The back should be ground flat or slightly concave. If you can see the mirror rock at all while you are polishing tool on top , this can contribute to a TDE .

Last edited by Sunfish; 06-08-2020 at 12:02 PM. Reason: Spelling
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  #382  
Old 27-12-2020, 09:34 AM
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mura_gadi (Steve)
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How do you cut thick glass blanks?

Hello,

I am looking at trying to take my blanks from a large sheet of soda glass and I am after help from those who have done the same.

So before I re-invent an old wheel any pointers or tips?

Here's what I thought I could do:

Below is a youtube video showing a great sales pitch for cutting thick glass, while the video shows the product being fool proof, the price is not within this fools reach. The kit listed gives a 404 error but I've sourced the hammer at about $500 USD.

I thought I could modify a "Automatic Centre Punch Adjustable Spring Loaded Metal Drill Tool" (ebay) which allows for interchangeable springs for an adjustable striking force. Then all I need is a similar head component with a washer and blunted striker head. The hole punch can be had for under $10.

But I am sure better minds than mine have been here before. So links, tips, tricks and traps and any other advice would be great.

I don't have access to a slow speed drill press for a DYI glass cutter.


Thanks
Steve
Youtube link:
https://www.youtube.com/watch?v=x-84Sdq7jaE
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  #383  
Old 27-12-2020, 01:37 PM
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sopticals (Stephen)
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What's the size of the sheet? and thickness?

Stephen.
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  #384  
Old 27-12-2020, 03:16 PM
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Size of Sheet

Approx. 1300x690x25mm Slab of soda glass - ie green at the edge from an previous ATM so I assume non-toughened etc.
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  #385  
Old 27-12-2020, 03:39 PM
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Rainmaker (Matt)
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Prestige Metal Works in Fyshwick can cut it into discs for you using their waterjet.....
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  #386  
Old 27-12-2020, 03:47 PM
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Quote from ACT Steel works

ACT Steel Works quoted $770 for 3 420mm, with 4 220mm and one 340mm cut from another sheet. Prestige Metal Works would not give a quote till they had cut a blank to work out the time and costs.

The waterjet saving is not having the disc plus 10% waste as the video showed, which is very nice. I have added extra as I am pretty sure I will have TDE and I'm just looking to bank/baffle the mirror down to 16", 12" and 8" etc.

PS. Matt(Rainmaker) I sent a pm regarding the estate purchase
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  #387  
Old 28-12-2020, 11:03 AM
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Had 4 sheets float (2.4m x 1.2m) waterjet cut back in 2014 by Aquajet NZ (Napier) sheets thicknesses from 34.1mm to 37.1mm. Cost was NZ$4000 to cut 39 blanks ranging from 12.6"-33" diameter.
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  #388  
Old 28-12-2020, 02:41 PM
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nice glass

Do you know/remember if there was a limit on how close the discs can be together or from the edge of the sheet?



Steve
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  #389  
Old 28-12-2020, 05:05 PM
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Checking original cutting plans I see I allowed 1" from edge. Probably could have reduced that to less though. Some of the sheets had some edge damage so allowed a margin for that.
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