During a cam swap I found one cam bearing spun and the others looked horrible. After installing new durabond cam bearings the old cam would not even come close to going back in, so I used the "cam cutter" suggested on this forum.

The first pass removed a large amount of material from the 4th bearing and a small amount from the first bearing.

I used the scotch bright pad on the drill with WD40 to smooth out the surface of the cam bearings... I am not sure if that helps or hurts but it made them "feel" much smoother. I probably don't want to know what sort of stuff the scotch bright pad embeds in the babbitt,

After about 30 more passes I got to this point. Note: After I got the cam to go in and rotate smooth I pulled the entire engine apart, deburr, hone, clean, new rod bearings main bearings.... etc...