Re: Information on scribing hairlines

[P3D Dr. Bob Wier <wier@xxxxxxxxxxxxxxx>]

Here's a message (from another list I'm on) regarding making very
fine lines (in this case, sliderule "cursors"). I thought with the
experimentation going on here, it might be useful.

THANKS

--BW

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|Delivered-To: rete-outgoing@xxxxxxxxxxxxxxxxx
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|Date: Mon, 2 Jun 1997 21:15:41 +0100
|To: rete@xxxxxxxxxxxxxxxxx
|From: rap1@xxxxxxxxxxxxxxxx (Richard  A Paselk)
|Subject: Re: Information on scribing hairlines
|Sender: owner-rete@xxxxxxxxxxxxxxxxx
|Precedence: bulk
|Reply-To: rete@xxxxxxxxxxxxxxxxx
|Status:   
|
|Regarding the "scribing" of lines on slide rule cursors. I just looked at
|three cursors (from a c.1940 K&E, a c.1970 Dietzgen, and a c.1950 Lietz)
|using a 20x stereo microscope. In all three cases the lines are channel
|shaped: they are definitely not scribed or scratched on. The K&E and the
|Dietzgen have very smooth edges, and look like they may have been
|chemically etched, while the Lietz line has somewhat rough edges (fine
|chipping) and looks like a very fine saw cut.
|
|Obviously it would be easier to attempt the chemiscal etching. Glass
|etching pens have been available in the past and might be a good tool to
|use along with a mask since HF is rather hazardous and inconvenient to use.
|
|
|By the way, if you want to take the economy route for cutting and shaping
|your new cursors, just cut rectangles of thin glass to size with a glass
|cutter, then sand teh edges with wet-or-dry sand paper (220 for rough
|cutting then stepwise to 600 for a really fine finish). It takes a while
|but you can nicely bevel the edges and round the corners with a little
|practice.
|
|Good luck
|
|Rich Paselk
|--- end forwarded text



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