The entire carrier can be tilted fore and aft by rotating the axles of the rollers. They are offset drilled. Side to side adjustment can be made by sliding the lateral support bars that the brass bars of the focusing mechanism pass through. After that, the negative stage can be adjusted using the four screws holding it in place.
Now I will tell you my dirty little secret for adjusting the lens stage. I use shims under the main support. Much easier, particularly for side to side adjustments.
Can we assume you have used a level
on baseboard and film plane?
A level uses surfaces which themselves may be
imperfect planes. Both pressed steel or aluminum
at the film stage and warped base boards can give
false readings. Levels thenselves do not guarantee
level. I use the projected image of the negative
carrier itself. Dan
If it is a F60 then there are not many adjustment options - it is just an F30 on steroids. If the projected image is square (check by measuring the two diagonals), but one edge is unsharp, then the lens has to be displaced. I wonder if the lens extension mechanism (a solid sliding baffle unit, not bellows, on a couple of friction drive rods, I think) is binding and twisting the lens slightly at enlarging distances. If so, I would expect it to be worse at small enlargements. You should be able to go from postcard to 12x16 in with one of these without trouble.
If the lens is damaged I would be amazed if it was aligning to exactly a left-right error. You can check by unscrewing the lens a quarter turn (lock it up again afterwards!) and seeing if the sharpness location changes. If not, it has to be the chassis, and I'd look at the focus mechanism and 'bellows' first.
You might need to check that the 6x6 carrier springs (I think it is like the F30 in this respect) are equal strength, and that you are using it the right way up.
If the projected image is square
(check by measuring the two diagonals)
You have in mind that if the two diagonals are of
equal length then the projected image is a rectangle.
The isosceles trapezoid also has diagonals of equal
length. None of it's angles are right angles.
I've not aligned my enlarger in the last few years.
It's such a damn frustrating job. Proof of alignment
is on the baseboard or easel. As with the first time
through, a square will be used.
I'm wondering if square alone meets ALL the
requirements. I seem to recall that forcus all four
corners needed attention and was coupled with
the squaring of the image. Frustrating. Dan