Looking for a mechanical drawing of base of 40D

Is anyone aware of a dimensioned diagram showing the tripod mount and grip alignment holes in the base of a 40D ? I'd like to make up a plate with a couple of pins so that I can remove the camera and then put it back facing in the same direction.
I'll measure it anyway, but it would be nice to have something either more accurate than I can measure or at least verify against.
Thanks.

Steve.

Remove the camera from what?

The plate that has the alignment pins on it.

1000arms wrote in post #11480890
EDIT: Never mind. I did not have the time to download and check before my initial posting. I have since, and the information you want is not there.

Thanks. Someone seems to be sitting on the internet cable down here and the download kept timing out. I'll stop gnashing my teeth now.

Steve.

SteveInNZ wrote in post #11481137
The plate that has the alignment pins on it.

Sorry, I just am not following the problem you're trying to solve, and I'm curious if you're trying to engineer a solution that's already out there...

You want to make a plate, of some sort, that the camera will sit on? what will the plate be connected to?

In my case, I want to use it to align the camera with my telescope mounting system. I imagine a similar problem would exist if I wanted to do a timelapse over a long period (eg. A year) and still have the camera to use in between shots. If I use a standard quick release plate, the camera can be pointing in any direction relative to the QR plate any time that the plate is removed and replaced.

SteveInNZ wrote in post #11482596
In my case, I want to use it to align the camera with my telescope mounting system. I imagine a similar problem would exist if I wanted to do a timelapse over a long period (eg. A year) and still have the camera to use in between shots. If I use a standard quick release plate, the camera can be pointing in any direction relative to the QR plate any time that the plate is removed and replaced.

Gotcha. Thought maybe I could help, but you're beyond me Might also ask around the Astronomy and Celestial talk forum for some tips. I would imagine one or more of those guys must have dealt with the same or similar dilemmas.

SteveInNZ wrote in post #11480839
I'll measure it anyway, but it would be nice to have something either more accurate than I can measure or at least verify against.
Thanks.

Steve.

Just looking at the bottom plate of my 50D. Probably the same as your 40D, I'd guess.

I could set my 50D up clamped to the table of my milling machine and locate the holes and the socket within .001" or so with the digital readout.

But that's not necessary, and you can measure quite accurately yourself with just a dial or digital caliper.

The relationship of three holes is tricky to get accurately, but you don't need to do that - if you locate the two alignment holes accurately just make the hole for the 1/4-20 mounting screw oversize by .050" or so and alignment will be determined by the two small holes. And it doesn't matter if the distance off the centerline is a not precise, either.

To measure the center-center distance between the two holes, find two twist drills the right size for a snug fit and put one in each hole.

Then measure outside to outside with your caliper and measure the diameter of one of the drill shanks.

Subtract the diameter from the distance and you have your center-center distance - probably to an accuracy of +-.002" or so if your caliper is decent.

For increased accuracy, measure inside-to-inside the drill shanks and add the diameter, then average with your first reading.

If you use a micrometer you can get closer...


-js

Thanks for the advice. I hadn't thought about making the tripod mount hole oversize, but it needs to be oversize anyway of course.
I put the camera and caliper (turned on, zeroed and open to about the same width as the two holes) on the scanner, made an image and measured the scale in pixels/mm.
I came up with these numbers in case anyone else is interested. The tripod hole is oversize.

Steve.

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