Sharpening the Brand-New Sebenza

[Bringsteen]

I recently purchased a new Sebenza (Large, Left-Handed) and had anticipated a shaving-sharp edge. In my estimation, the Sebenza's edge geometry is perfect for holding a usably sharp edge. But I was a little shocked to discover that the edge was not truly shaving-sharp.

I have an old strop that I purchased from Tandy Leather many years ago. I rouged the strop and burnished the Sebenza's edge to sharper than razor sharp. It took a bit longer than it has taken me for comparably-shaped knife blades made of ATS-34 and the like, but I have never been able to make a knife this sharp before. It can easily shave ultra thin strips of skin from my thumb.

On a whim, I decided to try actually shaving with my Sebenza. I have virtually no experience with straight-razor shaving, but I was rather impressed with the Sebenza's ability to actually shave my face.

If you have not invested in a strop, I highly suggest that you do so. Do NOT buy a straight-razor style; buy one that lays flat on a table. Remember to keep the edge as low to the strop as possible while keeping the absolute leading edge in contact with the strop. On a new Sebenza, with patient light strokes, it will take you about fifty strokes on each side to put the finishing touch on the edge of your Sebenza.

 

[Scott Dog]

I agree. Regularly stropping my Sebs have kept them incrediblily sharp.

 

[Uncle Timbo]

Bringsteen, first of all welcome to BF. I'm new to stropping. I purchased a Busse air bleeder and could'nt be happier. I recently got my BG42 Seb back from CRK and the edge was very decent but it was a working edge. I was amazed at how the strop could improve it. I'm sold on stropping.

 

[Bringsteen]

Hillbilly.223, do you have a picture of your Busse air bleeder strop? It sounds like an interesting piece of equipment, but I scoured the net and could not find it.

 

[Rat Finkenstein]

Hillbilly.223, do you have a picture of your Busse air bleeder strop? It sounds like an interesting piece of equipment, but I scoured the net and could not find it.

Here is a pic of mine:

 

[RVO3VOM]

The Busse Air Bleeder Strop sold out a while ago. Here's a pic that I had handy. The wooden handle was omitted when I shot the pic.

Looks like RF got the other angle covered before I could post. :thumbup: He just forgot to include some CRK content.

 

[akubra]

Ok, so would that mean that if I stropped my Sebenza on a regular basis, after use, I could keep it sharp without the need to actually sharpen it with a stone? (Given that the edge isnt too dull already, of course.)

Ive never used a strop, nor am I good at sharpening, but stropping sounds like an interesting option to touch up an edge. I guess there is less of a chance to ruin a knife/the edge angle as well, as it dosent take off too much material... .
Is that correct, or did I get a wrong impression?

Id be interested to learn more... .

Nick

 

[Bringsteen]

Nick

Repeatedly stropping a knife will often result in a more obtuse edge angle than you started with, because unlike a stone, a strop bends around the edge. I tend to do no more than 3 to 5 stropping sessions before I need to actually resharpen the knife. The SAK Executive that I always have with me never touches a stone more than once a year because I regularly strop it.

I use a strop both for touching up an edge and for putting the final polish on an edge I have sharpened. Some woodcarvers prefer to use an 8000x water stone to put the final polish on their knives, but this requires far better fine motor skills than I possess. A strop is more forgiving--and less expensive--than an 8000x or 10000x finishing stone.

A final benefit of stropping is that not only will the edge be sharper, but it will stay sharp longer. Under the microscope, an unpolished edge has burrs, nicks, and pieces of bent steel all over it. But a polished edge (stropped or otherwise) has a consistent pattern of microscopic teeth. Once you have the right edge geometry (which the Sebenza certainly has) the trick is to get the absolute leading edge as smooth and consistent as possible.

A great source of sharpening and stropping information is "The Complete Guide to Sharpening" by Leonard Lee.

Sharpeningsupplies.com sells a strop for $13.00. I have never used it (nor have I ever purchased anything from Sharpeningsupplies.com), but a strop is a simple enough piece of equipment that it would be hard to make a poor one.

Thanks to everyone who posted pictures of the Busse air bleeder.

 

[akubra]

Interesting stuff-thanks.
So stropping buys me some more time before an actual resharpening is in order?! Sounds good to me. Im really dreading re-sharpening with stones, as Ive messed up a couple of knives by attempting to sharpen them, in the past.
Even though I think that my sharpening system (one of those Lansky kits), is partly to blame for that as well... .

Anyways-Im really cautious when it comes to my new Sebenza-I sure wouldnt want to mess up the blade on this rather expensive piece. Thats why I kind of like the stropping idea.

Final question-did/do you use any of those stropping pastes (containing abrasives) at all?


Thanks,
Nick

 

[Bringsteen]

Nick,

I've not used any stropping pastes. I have a small bar of stropping rouge that I bought from Tandy leather 16 years ago. I am 31 now and I will probably have the same bar when I am 80.

You may want to look into pastes or powders rather than the old fashioned bar like I have. One advantage of the pastes is that you can get them in various grits. In an ideal world I would do a two-stage stropping after sharpening a blade: first with a fine abrasive (2 or 3 microns) and second with an ultrafine abrasive (.5 micron). Sebenza blades are of such quality that you could certainly justify the time invested if you were to go this route.

Not only does stropping a blade make it sharper, it also polishes the blade immediately before the edge, which reduces friction when cutting through materials.

 

[Don M]

If you are rounding the edge with the strop you are either pressing too hard or you are using a backing for the leather that is too soft. Light strokes, at the right angle, do the trick. Also, lift straight up at the end of the stroke - if you roll the knife a little - even very little - at the end of the stroke, you will round it off.

If done right, stropping will work the entire edge, so you may never need to use a stone. If you want to keep the convex edge, that is the way to go.

You can use fine sandpaper (800 to 2000 grit) on leather to do sharpening when the edge needs more serious work.

Check out http://www.brkca.com/ and click on the convex sharpening tutorial.

 

[Bringsteen]

Don,

Sorry I did not reply sooner; I was away from the computer for a few days.

When I wrote that over-stropping could make the blade obtuse, I essentially meant convex.

Even when you are using extremely light pressure on a strop, the leather (or synthetic medium) tends to become depressed ever so slightly at the microscopic level. This is what can give the edge a slightly convex shape.

I read your instructions on how to make a convex edge. Thank you. I had not seen that information before. I like a convex edge for knives that will see harder use, but for those that are more for light duty, I find that the convex edge does not provide enough relief for easy cutting. I suppose it is a question of edge durability versus absolute sharpness.