That may be fairly quick and easy Doc Drew. Might be just a round punch making regular dimples along an untwisted layered bar. Round shapes are displaced out of the straight layers, then when the grinders level it back out it could look like 'pool and eye' pattern. Maybe taking on an oval shape because of some drawing out of the length of the bar.

oops, it does say 'without making torsion'.

Last edited by craigd; 12/24/14 01:34 PM.