Been helping a local one-man repair/job machine shop out. He has a 4"/100mm boring mill and got put on it for a few jobs.
Re-bored a 3-1/2 bore hyd cyl out of a log grapple to 4" because the mfg updated the design and the owner only wants to stock 4" packing kits, as he trashes these on a regular basis. Used a Devlieg micro-set intergrated shank tool and had to stick the spindle out a bit to get 19" to the bottom. There's supposed to be like 4 more of these to do soemtime. Takes about 4 hrs to setup and bore.
This is the link the goes between the stick and a processor head on a log shovel. About 6" sq section solid. End bore was trashed. Bushings had turned to gravel and gotten beaten in the bore. Supposed to be 3". Had to overbore to about 3-5/8 to clean it all up before welding up to about 2.5, then bored back to 3.000 for a 3 thou press on new cat hard bushings. Cat bushings are nice because they cut them to press fit size for an on-nominal bore, so you don't have to figure fit out. These measured 3.0025 out of the box.
Here's the swing tower off a cat 305cr mini excavator. Bored the un-bushed pivot holes from a ovaled out 90mm to 3.625 to clean them up. A new, larger pin was made up.