You guys are going to laugh at this one. Some of you may just go into spasms. Early in my career I spent 10 years as a heavy equipment welder/repair guy for a utility contractor. We had our share of line boring done. That's my first learning of this whole machining thing. We did so many six way blade repairs. You always had to build up and regrind the back of the blade a good long straight edge is good here. Then you build up the tilt frame that rides on the blade. Build it up extra and use extra shims. It gives you extras to pull out as it wears out again. If I recall most of the bores had no bushings because the pins were fixed.
The most common bore fix that we did, and I know this would be better for the welding forums, was to build the hole back up to size and grind them back to fit. This took some doing to get right. You weld it up then take a sacrificial pin and smack the hell out of it into the bore. Then you beat it back out and smooth with a torch and or die grind the hi stuff. Kind of like scraping machine ways. Except no Prushn blueing. I know that this sounds barbaric and crude but we could make a machine tighter than they came from the factory (which isint hard to do. Most machines are so loose brand new thats is just stupid) as a note we bought all of our pins and bushings from the machine manufacturers. We just found that on the single little 6" long pins we could do it with out taking it all apart and not have to setup the boring bars. Which couldent be used on the ones that the machine was in the way of the other side. On things like loader buckets it was always done with the boring bars. And stacking links and boring them on the vertical mill was done a lot. It made the centers dead on even every time.
Master of unfinished projects