I have been trying to align my newly refurbished Omega D-2. I recently was able to borrow an alignment tool made by Bessler and am using it with D-2. Alignment itself was not a problem. Baseboard to lens stage to film stage. All fairly well aligned all within about 1/5th of a bubble. But, the problem is repeat-ability! If I align it at one height, move the lamp assembly up and down, focus knob right and left, and re-measure, I read differently. Do it again, and it is yet, again, different. Everything is/was tight and there are no obvious "slops." I soon realized, expecting this machine to align and repeat with precision of a highly calibrated scientific instrument is, probably not realistic. Not only is this equipment over 50 years old, is simply isn't made with that kind of precision. So the question - at what point, is it good enough? For a point of reference, I do not expect myself enlarging to any bigger than 10x14 using 35mm or MF negs. I do crop some times and my lens is NOT an APO type.