Re: ATM chasing spheres $%$^&*(%^&$%^!!!!!

[PFAFF2@delphi.com (Robert C. Pfaff)]

>Cary Chleborad wrote:
>> 
>> 
>>         I've been grinding an 8" and I'm having trouble acquiring a shpere.
>> I'm using a channeled aluminum tool (TOT) and stroking from center to
>> left at about 10 strokes a minute.  I've tried stroke lengths from 1/8D
>> to 1/3D and I just can't seem to get a sphere. I'm talking about a rough
>> sphere, I'm in 120 grit stage and usig a graphite test.  Also, I don't
>> think I'm being impatient, because I've spent five hours on 120 chasing
>> spheres.  Any ideas?
>
>
>#1 I'm using and aluminum tool 3/4" thick.  Since I was applying
>pressure to the over arm by hand, I thought that I might have been
>getting carried away and flexing the tool (doesn't seem likely).  I
>added approx 4 pounds of weight to the pin & stopped applying pressure
>by hand.
>
>I'll be damned If i can figure out what is going on...help! (please?)
>
>-Cary Chleborad
>

I guess it could be several things. Is the aluminum tool
making contact over the whole surface ? Are you using a full size tool?
How is your stroke?

IMHO I would switch now to a full size tile tool. The tile
being near the same hardness of the glass should grind in to make
better contact then a soft material like aluminum.
There some on the list will disagree with that but
that the way I see it. The stroke
with an automatic grinding machine is a sine motion with a
somewhat of a pause at the ends of the strokes. Try less weight
on the pin. You are smoothing now not hogging a sag.

Happy grinding
Bob Pfaff