I am interested in knowing how the machinist that did this grease barrel knurled it with a single-direction knurl???
I've attached a pic of the grease barrel and a scan of knurling rollers...there is basically only two knurls; the crosshatch, and the straight knurl...In different pitches, but that's about it...
The only way I can think of to get a single-direction knurl is using two identical sets of knurl rollers, and use both right rollers or both left rollers, of the cross hatch set...
Even then they would have a tendency to 'ride off' to the side while knurling...
(The clamp type tool post knurling tool in the pic is the one I received; replaces the 'run it in' knurling tool I've used up to now - it is much better)... 
And looking close, Neil hit it on the head...That grease barrel is crude...
