Keeping D3 in alignment

I guess 60 or so years is not a bad run, my D3 now has a slight warp in the front right corner of the negative stage. It has never been dropped, has been set on the same bench for past 25 years or so, no idea how it warped. Spent an hour attempting to get back in alignment before I took a really close look and noticed the bow. With the shim in place it is now level, don't have a laser tool, with level it is good. My shim is made of card board and gaffer tape, will to keep checking to make the cardboard doesn't thin out over time.

Thinking about taking the negative stage off and seeing if a machine shop and weld up the corner.

The first time I tried aligning my D5 I got things twisted around enough that the negative stage appeared warped. After putting things back as they should be I was a bit more careful and the stage was flat again. Since that time, I've made a little modification that makes it easier to align as well as make prints up to 30". Originally, it was going to sit on columns and shims added for alignment but I couldn't wait and used what was at hand. It turned out to be very rigid so the bar to make the columns went into the material bin at work.

I took the entire assembly apart and used a machinist square to make sure the stage is warped, less than 1/64 of an inch, not much and at F8 or 11 likely did not show. The D series were built for use, that's for sure, no wonder the military selected and used Omega for decades. Interesting set up you make.

A picture would be nice, otherwise just a guess. I it this part that is bent? From what I recall, it is aluminum, so you should be able to bend it back without too much trouble. As long as the negative holder sits flat without teetering it should be fine. You will be aligning the lens to the negative holder anyway.

Did not think to take picture when I had it apart, but pic you posted looks to be same part, the lower negative stage. Your right it is aluminum, was too timid to try and bend back myself. Next time I need do a realignment will make the effort to correct the warp at the moment it is ok. I try to keep the negative stage, the negative carrier and lens in alignment. I need to replace the 2 leaf spring that hold the lens board in place, been looking on line, have not found any. I have an old Air Force text negative, but it's 35mm, I use 75mm, 90, 100, 135 and 150 as well, as the 50 to 100 use the same flat board I pretty sure all these lens are in alignment if the 50mm is, the 135 and 150, not as sure.

no warping problem on my d2! trade those new fangled things in for a more venerable model !!!!

Woodcraft sells relatively inexpensive granite surface plates ($46 USD for 9x12 inches) that you can use to check flatness, and possibly use as a reference surface for bending.
Surface plate

D3 is a D2 with auto focus. I got it used without the matching lens for the v tracks, so at this point it is really a D2.