First a bit of background on Climax Locomotive cross boxes: These very complicated examples of the pattern making, casting, and machining trades are large two-in-one bearing housings that hold the truck gear shaft and locomotive axle in the proper position relative to one another so that the gears mesh correctly. As built by Climax in 1919, the truck gear shaft hole (the hole clamped to the mounting fixture) was lined with an expendable bronze liner, no doubt because of its relatively rapid rotation. When the liner wore out, a new one was installed, and to this day the truck shaft holes are like new, even after forty years of use. The same cannot be said of the axle hole (the one being bored), which was built as an unlined, cast-iron-on-steel bearing. After more than 330,000 miles, the axle holes are in very sloppy shape.
The only remedy is to bore out the worn holes, and install bronze liners, just as Climax did to the gear shaft holes 91 years ago. Two of the six cross boxes must have been worn very terribly, as they were found to have already been bored and sleeved when the locomotive trucks were taken down, very early in the restoration effort (today it was discovered that one of these already sleeved cross boxes was bored almost 1/8 inch out-of-square. The solution for this has not been decided upon).