Thread: Working With The Zulu Grey.

Originally Posted by Euclid440

Philipp, what is the theory of convexing the finisher?

You are just polishing with a smaller part of the hone, really the same effect as using a Rolling X stroke.

I have heard that Dovo uses a convex hone to finish their razors, but it Iis never explained why, and their finished razor are not a testament of great edges, though sometimes close.

I love that you are pushing the envelope trying new techniques, but I don’t understand the convex finisher.

Do you do a straight or a rolling stroke?

Hi Euclid440,
As far as I know Dovo does convex his stones in both directions: from side to side and lengthwise from one end to another, so its a spherical form.
SuperiorShave does explain it in one of his videos. My personal opinion is they doing it for ease of use and error tolerance. Somewhere I‘ve seen how a Dovo-Honemaster was honing a razor on a Coticule, she was wiping that blade with a crazy speed over the stone. I can never imagine that can lead to a good edge, but guess they can achieve consistently 80% of the target in 20% of the time and save money by that.


In my case I convex only shallow hones and only from side to side. Lengthwise my stone are as flat as possible. My hands are not very stable. In 100 strokes I can find myself slightly tilting the razor couple of times accidentally. In case of untilted stroke the razor contact the stone on considerably large line of the edge, the pressure is distributed to all area of contact. In case I‘ve tilted the razor only small part of the edge is running over a very small point on the side of the stone. So consistency of the strokes is low. I imagine that this one tilted stroke brings my edge considerably back if not negliging work of all the strait strokes done before.

Now if the hone has a light side-side convexity to it then regardless of the stroke being tilted or not the area of contact has always the same size so the strokes are much more consistent.
Additionally if the razor‘s edge has a small bend to it or a frown it’s still get in contact with the stone.

The back draw of the convex hone is the higher effective pressure of the edge to the stone (by the same pressure of the hand to the blade) compared to the stone with a flat surface. But there are some work arounds available to further reduce the pressure.

My personal magical threshold is the width of ca. 4cm for the stone. Bellow of it there is a risk of tilting the blade, above I can guarantee a full contact strokes throughout the honing session.

On the convex stone it can still be a straight type of stroke or a rolling stroke, depending on the geometry of the blade.

Regards

Philipp