The seller finally returned my calls... when he mistakenly called back thinking I was his mechanic!
Anyway, as expected, I was told to pound sand, noting it was my responsibility and all that.. Though he really stuck on that it was a 2016.... Even though I'd noted Cat had even said it was a '13.. Oh well, at least that's some form of closure there.
I should probably start a new thread on this... but what's people's take on welding build-up and line boring to the factory diameter vs line boring and sleeving to get to factory?
My planned setup for the boring jig is a doozy, but granted I don't try and take huge cuts, should be okay, though machining weld with a HSS cutter can be goofy from my experience... I 3d printed a long tube with the OD being the factory ID of the bore (50mm) and the ID of the OD of my boring bar (1"). It also helps to get an idea of exactly how out-of-round the bore is near the end... If I'm boring out, a 10mm oversize bore (60mm) should get me there.
From there, I have enough good metal in the middle of the bore to fit snug and align my boring bar axially within it. I have 1" pillow block bearings, one that I'll bolt onto a 1/4" end plate, and another that I'll put on the table of a bench drill press with the base removed(picture for reference, no bearing on it yet).
With that, I can run the boring bar through with my insert with the end plate and table on the bar, and while aligned, get those welded to the stick with some angle iron or allthread, making sure at least one of those is far enough away from the exit of the bore to get my alignment insert out.
To get going, I just need to slide the boring bar in, insert a cutter into it and set it for the first cut, then mount the drill press to the table via. the table clamp. The boring bar will be turned down to fit the chuck on the press, so that'll be snugged down and I should be in business. The press only has a few inches of stroke in it's feed, so I'll just need to inchworm using that, backing out, then advancing the entire drill press down the table to then start again.
It aint machining that'll win any awards, but it should do the trick for getting a half respectable bore for less than 100 bucks (not counting the benchtop press that was destined for the scrap heap anyway...)