Philippine sword; Insurrection piece or WW2?

[Shakethetrees]

Here are four examples of vertical sanding at the ricasso.

The first is a Nepalese Baker bayonet. The images show it as very light, but it's easier to see it in person.

The second is a French mid 19th century cavalry trooper's saber. (I'm not sure of the exact model date, but I'm confident of the general timeframe.)
Fairly clear here.

The third is an imported German (Solingen) made blade on a Model 1840 US cavalry enlisted saber with Confederate provenance. Again, very clear in hand, less so in the image.

The fourth is a Saxon heavy cavalry broadsword, c. 1730 that I posted to the European forum a month or so back. Fairly clear in the picture.

These four are what I could put my hands on with a few minutes notice. In time I could get a few dozen examples from all over the world.

But, and I think I belabored the point a bit, this was a very common finishing trait that was used all over the world, wherever powered machinery, (steam, water, electric, or other) was used.