[SGVHAK] 3-D print a magnifying glass?

[John Kreznar]

In a posting purporting to be from Claude Felizardo
<cafelizardo at gmail.com> but lacking a digital signature, it is written:

> What is your application for wanting to print a magnifying lens?

It's to replace a lost pocket magnifier that was my constant companion
for over 30 years and that I used for everything from reading fine print
to inspecting small objects.  It was unframed glass, all chipped around
the edges with scratches and even a blob of superglue one the surface,
but still eminently useful.

My first stop was http://www.scientificsonline.com (Edmund) where I
found http://www.scientificsonline.com/giant-5x-stand-magnifier.html,
2.5" diameter, 5X, $10.95.  Good price, and I could remove the stand and
provably be back where I started.

But in spite of fond memories of Edmund, I don't like their current
business practices.  Further, I'm beginning to try to move to Bitcoin
for trade whenever possible, and a low-priority project like this is a
good starting point.  Anybody have one they want to sell for Bitcoin?

Of course, there's nothing "Bitcoin" about a 3-D printer, but I thought
I'd also use this occasion to tap SGVHAK's collective wisdom about
current 3-D printer capabilities.  Looks like they're not yet good
enough.

> I think a magnifying lens has to be concave ...

convex, for sure

> ... if it's flat on once side then you've cut the power in half no?

Hence my idea of cementing two together.

> A fresnel lens cuts down on the volume of material needed and space
> but I don't think you really want to try reading through one for any
> length of time.

Agreed.

> The resolution of 3d printers are in the order of fractional mm but I
> think you might need something finer?

No doubt.

> I would think there would be so much optical distortion I can't see it
> being useful for reading.

Yep.

> Okay, looking around...

Thanks for the links.  Following them now.

-- 
OpenPGP key: http://ininx.com
 John E. Kreznar jek at ininx.com 9F1148454619A5F08550 705961A47CC541AFEF13

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