Thread: The CBN Project

So if you have read this thread: http://straightrazorpalace.com/strop...wool-felt.html

You'll know that I got some .25 diamond spray and threw it on a nice hard pressed felt strop. You'll also know, that I wasn't having too much luck with it - as I felt it made my blades too keen and produced a harsh shave.

OK so I hadn't finished experimenting with the .25, but I got a PM from Marty who said he might be able to help. Since he offered to set me up - how could I say no?

His solution? CBN!

I never tried the stuff, so I was more than glad to give it a shot! His package arrived at my door today. Thanks Marty!!



One treated paper strop and a water spritzer.

Here it is hanging on my towel rack.



Now I was also given instructions, but for the sake of time, the key things to note is that I am to work my blade on some .25 diamond, but then work the blade over the .5 CBN for a bit, followed by the .125 CBN.

He assures me that this, even after the .25 diamond which was causing me to have too keen a shave, will create a smoother experience. The spritzer is so I can mosten the paper treated CBN strop before use.


To put it all to the test, I have chosen a blade that has always straddled keen just off the stones. I have calmed her down and love the blade, but if this stuff is to do what is claimed, this is the perfect blade to experiment on - that and i know the blade well.


The test subject

To be fair, I touched up my Boker this evening and just shaved with it - lovely and smooth.

This weekend, I'll apply some .25 diamond to it. I expect it'll be hell. After confirmation of a too keen blade, I'll begin the CRN treatment.

I intend to strop the first day using the CRN with both the .5 and the .125. Then I'll only strop the blade on the .125 for 7 more shaves before seeing how long I can go without any treatments.

It should be fun!!

I am posting now as I go along to bring anyone who's interested along for the ride. That and so I can post when its all fresh in my mind.

I'll report back sometime this weekend.

'Cutter, I think you're gonna be a happy guy. Thanks to the honorable Riooso, my first experience w/ CBN was excellent. I use more strokes than diamond, but again, I'm using a pc of hard felt 4"x6" total. After stones, I might give that little pad 10 strokes & be amazed. Smoothness & Sharp give each other a big sloppy wet one.

I mostly reserve the sprays for wavy blades. I can fairly reliably do it on the stones, but its a PITA.

Another thing your sequence tells you is that getting some nasty sharp w/ diamond isn't a problem if its not the last finishing operation. From there, finish on CBN or a natural of your choice.

I already know you're gonna like it. You might ask the Honorable MrSell to weigh in on sprays & pastes. He's tried more than I ever will & has some experience at picking the fly poop out of the pepper.

Have been considering CBN for quite some time. It will be interesting to see what you think of it.

Way to go David, I love reading threads like this where somebody actually takes the time and patience to experiment, rather then to just type

Quote: He assures me that this, even after the .25 diamond which was causing me to have too keen a shave, will create a smoother experience. The spritzer is so I can mosten the paper treated CBN strop before use.[QUOTE:]

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David
Just out of curiousity, what kind of paper is on your hanging strop with D-rings? Did you make it or did you buy it? I don't understand what kind of paper it is.

Thanks in advance. I have been using CBN for a few years and it is less harsh than Diamond as you stated.

Same kind of results here over the last few years, but with 0.125 CBN on a rigid paddle covered with roo skin. Seems like you can do a large number of passes on it without the edge dropping off - it reaches a degree of smoothness, then stays there.

Also like stated above, I use a mister to dampen the CBN - unless it is freshly sprayed of course.

I don't use it all the time - a small percentage of the time, to be honest - as the edge of the SG20k or a good thuringian is plenty smooth enough for me.

Regards,
Neil

Great stuff

I have been hearing about CBN for ages, never tried it. What I fail to understand, is how can it, or any abrasive no matter how mild, improve an edge that is already honed and stropped on diamond, to the extent that your Boker test razor is ? It just seems to me that the edge would begin to become to thin at the apex and begin to fail. If not immediately upon meeting up with the whiskers, sooner than if it had been honed to a point where it was a smooth shaver and left at that ?

I'm not being a critic here, I'm asking an honest question because I don't know, just assuming. I have a 30x eye loupe and a 40x microscope but I don't use the micro much anymore and it is not equal to these higher power USB style gizmos. So I don't fool with the close up views that some of our members check out their edges with. It just seems to me that honing and then stropping an edge the way you've described would end up being too much of a good thing ? Anyone have any thoughts on that one way or the other ?

FWIW there is a guy, japanese, who hones kamisori. Forgotten his name, unfortunately. As he finishes, he uses paste/powder or an abrasive of some kind. The idea is to get rid of any trace of a 'false edge' or what I suppose we would term a microscopic micro-burr. Then he goes back to the finishing hone for a few more swipes.

I have seen such an edge - a 'false edge' to use his words - myself, only it does not look like a 'fin', 'foil; or burr, it just looks like a regular edge. I guess that is because it is so small. It only reveals itself during stropping or shaving by breaking up and deflecting. It is much smaller/finer than the fin produced by over-honing. It is not always there either. But when it is, CBN (or another abrasive) clears it up and is quicker than running the edge through horn or cork (or going mad and running it over the edge of a bit of glass), dropping down a hone or two and working back up again.

I always inspect the edge under a 20x loupe during, before and after stropping. If the edge looks like it has a lot of really tiny micro-chips, then greater mag usually identifies either the presence of a false edge (a barely discernible line down to where the pitting is) or, on the other hand, if there is no trace of a false edge then it is the steel that is poor.

It doesn't occur all the time, of course, in fact it hardly happens - to me, at any rate.

But in this case I think going to the compound achieves what that old japanese kamisori honer was getting at.

Whether that is truly the case or not doesn't really bother me - only the results do, and I have experimented enough over the years with CBN to know that it works for me when needed (as it does with other abrasives like chrome-oxide, cerium oxide, stannous oxide, etc).

If the steel is not good enough to sustain such an attenuated edge, then of course CBN (or any other fine abrasive) will not help. It doesn't help much with an honest-to-goodness foil-edge caused by over-honing, either, as far as I know.

Regards,
Neil

Jerry,

I just noticed your sig. line:

JERRY
Hair straight back, Balls on fire, baby!!!

Sounds painful! I'd go see the doc about that, he might be able to prescribe some soothing cream...

Regards,
Neil