Re: [ATM] Quandry over steel washer tool

[Jim McPherson <jim@eflightproducts.com>]

I've always considered a washer tool to be good only for grinding after 
the initial curve has been hogged out.
It seems to me that a "tile" tool made with washers will never grind 
down as your glass does, thus staying
roughly flat and then by the same action, making your glass go back 
flat. I suppose it might work with a very
slow focal ratio, but I doubt it.
I'd suggest hogging out with a steel tool like a pipe flange, then 
making another washer tool after you get the hole dug.

-Jim

Mark wrote:
> Started today, a 12" plate blank using a stone tool topped with steel
> washers.
>  
> Unfortunately, when I made the tool, I didn't realise that the washers had a
> bit of variation in thickness.  If
> I had, I would have put them on the blank and poured the stone over them.
> But, as it was, I made the
> stone "blank", then epoxyed the washers to its top.
>  
> So now, after 6 hours of hogging with #80, only about 1/3 of the washers are
> showing contact and
> the blank is not deepening very fast.  Have about 10% of the sag after the 6
> hours and the wear
> is not well centered.
>  
> Should I gut it out and continue?  Should I trash the tool and start a new
> one?  I have no more washers but
> I do have 1x1 tile...but I've heard that tile is not the best thing to start
> a flat blank with.  I do have another
> 38 pounds or so of Hydrostone :-)
>  
> Any help is appreciated!
>  
> Mark
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>
>   

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