Subject: Making small round mirrors

From: [email-masked] ()
Date: 31 Dec 1994 16:24:37 GMT

Hi, gang! I'm going to make a do-dad to wiggle the output from 
one of those visible-wavelength diode laser pointers, that are becoming 
cheap at last ($50.- in Santa Rosa). I've done this before, using 2 
surplus R/C car motors, each one mounting a 1" square front-surface 
mirror on the end of its shaft, fastened in place with a glob of hot 
glue. The trouble with this was that the mirrors wobbled about and the 
sharp corners could nick you if you weren't careful. What I plan is to 
cut a round segment out of a couple of these mirrors and mount them in 
turned aluminum "cups". The technique of cutting a round piece of glass 
is not new: you just chuck a piece of brass tubing of the diameter 
needed, being careful to notch the end of the tube in a couple of places. 
Then you apply an abrasive-water slurry to the glass and bore away. What 
I want to do is to insure that the delicate front surface mirrors don't 
have their coating damaged while this is going on. A coating of some sort 
must be applied and then removed after the cut is made. Any suggestions?

--
"Steamboat Ed" Haas		:	Co-founder of the 
Voice: 805-968-7534		:	    SBSMEEBBQ
FAX:   805-JOB-TWAT		:	-Call about our Newsletter!
	--------Decks a-wash in a sea of words!!--------

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From: [email-masked] (Erik Halberstadt)
Date: 31 Dec 1994 09:59:05 -0800

[email-masked] wrote:
: 	Hi, gang! I'm going to make a do-dad to wiggle the output from 
: one of those visible-wavelength diode laser pointers, that are becoming 
: cheap at last ($50.- in Santa Rosa). I've done this before, using 2 
: surplus R/C car motors, each one mounting a 1" square front-surface 
: mirror on the end of its shaft, fastened in place with a glob of hot 
: glue. The trouble with this was that the mirrors wobbled about and the 
: sharp corners could nick you if you weren't careful. What I plan is to 
: cut a round segment out of a couple of these mirrors and mount them in 
: turned aluminum "cups". The technique of cutting a round piece of glass 
: is not new: you just chuck a piece of brass tubing of the diameter 
: needed, being careful to notch the end of the tube in a couple of places. 
: Then you apply an abrasive-water slurry to the glass and bore away. What 
: I want to do is to insure that the delicate front surface mirrors don't 
: have their coating damaged while this is going on. A coating of some sort 
: must be applied and then removed after the cut is made. Any suggestions?

: --
: "Steamboat Ed" Haas		:	Co-founder of the 
: Voice: 805-968-7534		:	    SBSMEEBBQ
: FAX:   805-JOB-TWAT		:	-Call about our Newsletter!
: 	--------Decks a-wash in a sea of words!!--------
: 					
I haven't tried it myself but, you may be able to get away with one of 
two artist's products, either of which should be no problem to find in 
Santa Rosa. My first guess would be liquid frisket or "Art Masking Fluid" 
made by Windsor and Newton, which you should be able to get at Standard 
Brands. Cost: about $5 for 75 ml. It's a liquid latex material, fairly 
durable and easy to remove. Next guess would be frisket film which might 
not be so easy to find or remove.

Good luck!

Erik

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From: [email-masked] (tony gray)
Date: Mon, 2 Jan 1995 01:01:37 +0000

> : cheap at last ($50.- in Santa Rosa).

What as a matter of interest is a visible-wavelength diode laser pointer
and what is it's purpose ?  It sounds fascinating !

Regards,
-- 
Tony Gray
Kent. England. UK
  [email-masked]

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From: [email-masked] (Andy Dingley)
Date: Mon, 2 Jan 1995 08:37:02 +0000

> : one of those visible-wavelength diode laser pointers,

> : have their coating damaged while this is going on.

Front surface mirrors ?  By the sound of this (RC motors & all) it's not a
high accuracy project. Wouldn't it be simpler to make your own mirrors of
polished metal, rather than to use these expensive & fragile front surface
ones ? That way you can cut first & polish later.

BTW - I've done a "for amusement only" version of this myself. I used a pair
of long-throw loudspeaker voice coils (cones removed) from car hi-fi bass
drivers to make linear actuators, and mounted the mirrors on a flexing beam.

-- 
Andy Dingley                             [email-masked]

Remember children:  'M' is for Monoculture and for Microsoft.

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From: [email-masked] (Alan Frisbie)
Date: 2 Jan 95 15:29:42 PST

In article <[email-masked]>, 
[email-masked] (Ed Haas) writes:
> cheap at last ($50.- in Santa Rosa). 

I bought a used laserdisk player from Halted Specialties in
Santa Clara, Calif. (one of the surplus outlets in the 
San Fransisco Bay area) for about $70.   After stripping it 
all down (lots of extra parts for future projects!), I was 
left with the HeNe laser tube, some front-surface mirrors, 
and an X-Y deflection mirror all mounted on an aluminum 
casting about 6" x 8".

I was able to drive the deflection coils simply by attaching
them to the "B" speaker outlets on my stereo system.   The
deflection angle is rather small however.   With the unit
sitting on the floor, the patterns drawn on the ceiling were
only about a foot across.   Also, the high-frequency response
was, as you might expect, rather poor.

--  Alan E. Frisbie               [email-masked]
--  Flying Disk Systems, Inc.
--  4759 Round Top Drive          (213) 256-2575 (voice)
--  Los Angeles, CA 90065         (213) 258-3585 (FAX)

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From: [email-masked]
Date: 3 Jan 1995 02:42:36 GMT

In article <[email-masked]>, [email-masked] (tony gray) writes:
[...]
>and what is it's purpose ?  It sounds fascinating !

It's a gadget about the size of a pen (or maybe shorter and fatter) that
uses a battery-powered solid-state laser to produce a collimated visible
beam; people use them for pointing at the screen when giving a talk
with slides or transparencies. Similar lasers are used are used to project
a red dot onto a prospective target in lieu of a gun sight, and I'm sure
there are many more uses that people in this group could suggest.

I was hoping to use one of these in aligning a telescope recently, but
found that the pointing stability of the best diode lasers I could find
was quite a bit worse than that of common HeNe lasers. 

                      ...when I sit down to write
Don Holly             my intentions are always blameless however deplorable
                      the ultimate effect of the act may turn out to be.
                                           --Joseph Conrad