EDIT - UPDATE: SUCCESS!

First of all, thanks for the help. I posted this question here because this is where all my knowledgeable, polite online bike friends are.

I did lower the derailleur a bit. I used an adjustable wrench to slightly bend the side plates because I felt they were part of the problem. Also I spent more quality time setting the limit screws, which is very hard because the spring is really strong and it's hard to hold it on the big ring as the crankarm goes by. The bottom line is that STIs need to be set up very precisely and are not very forgiving of misadjustment. Literally the last time I had to set up road STIs was when I was working in a bike shop in 1994.

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Hi guys n gals,
I'd love it if you could shed some light on a shifting problem I'm having. This is all in the work stand, by the way; I haven't ridden the bike yet.
I am working on a 1988 Trek 1500. It had downtube shifters and I converted it to STIs. Everything is Shimano *-6400 (Tri-Color 600/ Ultegra). It has a braze-on front derailleur. The spindle in the original (?) adjustable BB was badly pitted so I replaced it with a UN54. Old spindle was 117.5; new is 118. I replaced the chain with a new HG91. Brand new Shimano SIS SP cable set. Rings are 53/39 and the cassette is 7 speed.
Here is the problem: I can't get the front derailleur set so that there is no chain rub. In the small ring/smallest cog there is rub on the edge of the big ring. Not much that can be done about that. I know that there is a half click on the front shifter to help trim the derailleur when in the small ring. However, there does not seem to be a sweet spot where there is no rub when in both the big/small and small/big extremes. I know that the correct way to set up a derailleur is to set the limits, then the cable tension, but I've been going in circles for a couple hours. Also need to be sure I have the derailleur at the correct height. Any help would be great.

Campagnolo...

I have tricolor on a few bikes and don't have an issue with the FD. Perhaps you could post some pictures of the front derailleur set up?

It is normal to have rub in extreme gear combos, that is why you aren't supposed to use them.

By extremes I mean big ring/small cog and small ring/big cog; both are normal combinations to use and to my mind there should not be chain rub on the derailleur cage.

+1. Small chainring, middle to large cogs on rear; big chainring, middle to small cogs on rear. If you find yourself riding on the inner chainring mostly, you can shift the FD to not rub on the inner rings. You can also add a smaller washer to the FD at the screw that holds the 2 arms together, to widen it a bit.

It sounds to me like your FD doesn't have enough throw.
Start by setting the mech in the slack (low) position with the chain on small ring large cog. Make sure you have tension on the cable in this position.
After shifting the lever a full swing you are saying that the cage does not travel far enough to prevent rubbing when shifted to large ring/ small cog?
Also is the equipment new or used?

Precisely.
Chain, BB cables = new; the rest is used. Shifter is an ST-6400, derailleur is an FD-6400.

Derailleur mounted too low? Just a guess.

It's obviously near the bottom of the mount, and it looks pretty close to the chain ring. Maybe the shape of the cage would give more room if it was lifted upward.

Looking at those photos, I think, for one, your FD should be dropped down closer to the chain ring. Also, it appear that FD has been bent outward. Bend it back level and try again. it also appears that you have a larger cog set than original. Unless you are an athlete that rides mostly on the small cog in the rear and the large chain ring, I would recommend setting the FD to not rub on the inner cogs and inner chainring.

Maybe it would be helpful to see photos of the drivetrain from the rear in the "extreme" high/low gears that present chain rub, and also a shot of your exposed spindle. As I visualize it, if the cranks were to move toward the frame, the chain might gain enough clearance to avoid rubbing on the inside of the FD when in big chainring/small cog. Not sure where the rub is with big cog/sm chainring.

You mention a slightly, .5mm, longer spindle. I know it's not much, but the longer spindle could possibly be creating the chain rub. Or it's just a canard.

Lastly, perhaps a silly question: cranks all the way tightened?

Problem as I see it is in the shifter. One shift not moving the cage enough is either
A. Bent F mech arm
B. Cable stretching /not tensioned
C. Incompatible parts
D. Limiter screw
E. Shifter restraint

Rebuild the left shifter. Dried up grease can prevent full range of motion in the shifter arm teeth/gear interaction.

+1 . Have you checked Chainline?

Top photo, I agree, shows the derailleur a mlilimeter or two too high. I don't think that's the problem, but I'd lower it anyway.

Lower photo, see how the derailleur mounting bolt aligns with the slot in the fd braze on? Tthe head of the bolt looks a little off-center to the left (of the bike). When you lower the derailleur, see if you can rotate it a little bit on the vertical axis, so the head of that bolt moves a little to the right (of the bike) to bring the derailleur cage to the left. Only the tiniest rotation should be required.

Well, that's my guess, anyway. Good luck!

Alignment of the derailleur cage with the chainring or chain? A little change makes a difference. Some sources say align with big ring, some with chain (in big ring, small cog.) Try it both ways.

Haha, everyone disagrees with me. It looked a lot lower last night, maybe I mistook the rear of the cage with the front of it.

OFG is right, it did come with a 113mm BB.

You're posting this to C&V? The obvious answer is friction shifting.

Front derailleur cage is kicked outboard just a hair relative to the big ring.

That, and the BB may need to be the original 113 mm length.

(You beat me to it)

Update: see Post #1