Re: Home made Lenses ( was Large Format Lens Question. Low techanswer)

That drill press idea was basically how the machine I had functioned......
The bronze bearings ( some will have Needle bearings ) certainly will not
hold up if used a lot in this fassion for long especially if the slurry mist
gets into the works......... You would dope a piece of glass in a holder
and
press it onto a mold that is revolving using grit in-between...... I
actually like the drill
press Idea better because you could form a dam for the slurry.... .........

        I recently built a glass drill using a cheap Chinese drill press
that I bought new for $35..... I made the drills out of steel V pulleys
used for fan belts. I then tack welded strips of perforated metal screen
to the parameter of the of the pulley....... I then make a dam and put a 100
grit slurry in it and drill the piece of thick glass...... I made a set
that would go from 3 inches up to 12 inches in 1 inch increments...... for
Smaller sizes I just bought diamond drills.

Correction The name of the book I mentioned before is "Lens work for
Amateurs"...

----- Original Message -----
From: "Jack Brubaker" <jack@jackbrubaker.com>
To: <alt-photo-process-l@skyway.usask.ca>
Sent: Sunday, February 27, 2005 2:50 PM
Subject: Re: Home made Lenses ( was Large Format Lens Question. Low
techanswer)

> John Cremati Wrote:
>
> ......... I used to have a old lens making machine that
> > was simply a lens mold rotating on a centered arbor.... You would put
the
> > glass by doping with hard wax on a arbor and then put this in contact
with
> > the mold..........They still make these machines... Salem Distributing
sells
> > the various grits, polishes, exc..... http://www.salemdist.com/
> >
>
> One could use a drill press in place of a specialized lense grinding
machine
> .My Dad used to make specialty lenses for research projects at the U. of
> Chicago by mounting the glass blank on a shaft that would fit in a drill
> press. I don't know the details of what they used to grind the glass
against
> but the two surfaces sat in a tub of water and abrasive slurry. The drill
> press was run with a weight hanging on the operating arm. The operation
> could take days and was very hard on the drills bearings (not used to
> continuous turning under load). He often referred to the drill press they
> only used for non-precision work as the one with worn bearings from
grinding
> lenses. A more modern machine with even cheap ball bearings would probably
> handle the job with ease.
>
> Jack
>
>
>
>
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Received on Sun Feb 27 16:55:12 2005