P3D Stereo Projector Question

[Michael Georgoff <Michael_Georgoff@xxxxxxxxxxxxxx>]

I've decided that rather than spend between $200 and $500 on a stereo
projector, I'm going to hack one together out of an existing pair of mono
projectors.

I pose this question to those on the list who have been inside a stereo
projector and have an understanding of how "manufactured" stereo projectors
work.

When setting left and right projected images on a screen (horizontal
translation only), is it only the lens which moves, or is it the entire
"optical unit"?

I imagine that I will end up with two "optical units" that go like this:
Reflector, bulb, condenser, heat-absorbing glass, slide, polarizer,
projection lens.

Now, I could set each "optical unit" on a chassis/frame and fix the back
ends on a pin, and move the front ends via a screw shaft, essentially toeing
in and out...

or...

I could fix the back ends and toe in/out the lenses only.

Any advice?  My guess is that it may be optically better to toe the whole
"unit" in/out to set horizontal position of the left and right images, but I
am also guessing it'd be more garage level engineering than it may be worth,
as we are only talking "household fun" here in projection.  I have no
intention of using this hacked together unit for more that 5 or 6 humans at
a time (and maybe the family cat, if she'll sit still for the polarized
glasses).

Who's been inside a TDC?  What's it look like in there?


Thanks,

Michael Georgoff
San Jose, CA


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