Watching this vid made me think of the Petrie core...and then recalling the experiment conducted by Chris Dunn re: copper tube/sand abrasive drilling and core signature vs. Petrie core...striations weren't the same. Gets back to feed rates.
[www.youtube.com] 14:44 min mark.
Lot's of clues in this vid if one is looking for same. ;)
[www.youtube.com] 14:44 min mark.
Lot's of clues in this vid if one is looking for same. ;)