P3D Re: VM personal camera problem, please help

[Sid Herbage <sid@xxxxxxxxxx>]

At 02:13 PM 6/23/99 -0600, Dr.T wrote:
>I would too.  Also, let's not forget the cutter.  It is possible
>that the spacing of the gates/punches in the cutter is off.

Yes, I wondered about the cutter but the spacing in this is
even more "fixed" and close-tolerance than the camera if anything
and would closely follow the master tooling. If vm at some time had
a bad master tool set, this could happen which might mean a
considerable number of bad punches in the field (unless they
discovered the problem and this case is just an escapee).

I guess poor grinding (especially later re-sharpening) of the 
punch (moving) half could throw the spacing off but it wouldn't
affect the die-half and would likely only result in increased
punch/die clearance with consequent tearing at the chip edge.

>>I don't know what the normal production tolerances on image
>>spacing are likely to be but I would have thought that 0.03"
>>(1/32) would be possible...
>
>That's a bit too much for a precision part like the gates
>of a stereo camera... but what if the deviations of that
>and the punch gate happen to be in opposite direction?

Well I based the "possible" on the fact that the spacing is actually
set by the location of several times for each gate and these locations
are set by regular machined/punched features. (That is there seems to
be no special shimming in this direction to achieve extra precision).
With regular tolerances and the tolerance build-up over that many items
for two sides, I would have thought .03" was in the realm of the possible.
And yes, as you say, the cutter tolerance has to be added to the camera
tolerance

That's based on examining the assembly .... as far as the practical
requirements for decent stereo go, I'd naturally bow to you although
I don't really see why a greater precision than .03" in the spacing
of the two pictures should be necessary. Even in the case of the
VM where the chips are small and there is little control over the
location of the chips within the mount (reel). (And if it isn't necessary,
why would any manufacturer build in more precision than required?
It just increases cost.)
... sid (sid@xxxxxxxxxx)


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