Gary, I restored my 4x5 Korona this past year and had a similar problem with shaft and lock down washer at opposite end of knob. I believe they did not have a knob on the front left side, just a washer that "floated" and was retained by a peened end. I have looked at several and none had a knob, just washer-so you done good. There should be a slightly smaller dimension to the steel shaft at that end. Mine (washer) was missing, but I used a #10 or 8 zinc and had it brazed on by a machinist friend. Tends to creep just a tad when locking down but no biggie, as I rack out the front just past infinity focus then fine tune with rear. I did the same with rear shaft and also moved the gears over a tad on shaft as they had moved some over the years and made indents on the wood. So heated 'em up to loosen, positioned on track and resoldered. Then buffed it all out on the grinder with
polishing wheel.

The spring steel under the front standard is a bit weak, but I bought another 4x5 for parts and to use the front ext. as a rear on mine (empathy please).
I think a shim under these might work well too. I had basically taken the entire camera apart, ext. frames and all and reglued in a squaring jig with gorilla glue.

All in all a pretty stable camera. My only wish is that it would lock down tighter on the front shifts/swing block. But I'm working on that.

I bought the 8x10 version (it's momma) with all the front tilts and swings (like the 4x5) and will be getting to that soon.

For some reson I really like the Korona, maybe cause it's my first LF or it's uniqueness.

I have a rear standard from an EK 2D that I pieced the rest out on UPAY and am thinking I can incorporate the geared rear swing from this into the Korona rear. We'll see.

I used two pieces of 1/4" hobby ply for the lensboard and worked well. That way you can drill the outer circle and inner separately before gluing.
I'd like to see a pic of yours, and is yours an 8x10 or ULF?