The connecting rod boring machine I used at the machine shop where I worked part time for about 5 years could hold a .0002" oil clearance on a Cummins wrist pin bushing and do it without needing any finish honing, using a sharp carbide-tipped cutting bit. It could also be used to machine the big ends of con rods, but it needed to have coolant running to work steel. We usually ground or filed rod caps and finish-honed the big ends with a Sunnen PowerStroke hone to avoid setting up the boring machine for steel several times a day.
When I had a bunch of Stovebolt rods to convert to insert bearings, I did use the rod boring machine and coolant, but tying up a $60,000.00 machine for converting just a few rods was not cost-effective. I usually used a Bridgeport with a precision boring head to rough out the rods, and then cut the final .002" or so on the Sunnen hone. That particular shop didn't rebabbit rods or main bearing bores in blocks- - - -just not enough demand for the service to justify the cost of setting up for it, or training people to do it.
Jerry
