Hi,
the cbn rods are an experiment,
use lube,
both stones ought to last if you're gentle ( see bottom of post )
...
as spyderco sal glesser says
https://forum.spyderco.com/viewtopic.php?p=337564#p337564
Spyderco Diamond Rod Durability
by sal » Mon Mar 12, 2007 3:02 pm
Hi John,
Diamonds don't wear out! They are among the most abrasive resistant materials on the planet.
What happens is; first they "cap". This means that the very fine edges will chip due to excessive pressure or impact. This is the first 10 knives or so mentioned above.
Then what happens is the diamond is dislodged from the matrix holding it to the steel platform. The diamond is dislodged from the matrix by the user pressing too hard or "striking" the diamond. the diamond is pushed into the steel under it, which creates a cavity surrounding the diamond, permiting the diamond to move....back and forth....until it cuts its way out of the matrix.
The diamond requires almost no pressure to cut steel. drag a diamond hone very lightly across the blade of your most cherished collector pieces
I guarantee it will scratch the blade.
I continually hear about people that say their diamonds wore out. Not so. They wore them out by pressing too hard. Even the ones that say they are not pressing too hard, just don't know how lightly to use diamonds if you want them to last.
Diamonds are great, they'll cut the hardest steel. Pressing harder doesn't make them cut faster, it only dislodges the diamonds from the matrix. If you treat a diamond abrasive like a whetstone, you are pressing too hard.
I personally like to lube with a little water which I beleive reduces the cut but saves the diamond.
That is my opinion based on a background including: experience in Mil spec plating. 55 years of knife nut passion, manufacturing diamond hones, sharpening experience with just about all abrasives.
I would not let the scouts use diamond hones without prior successful sharpening experience. I would bring a very coarse cheap 2x8 or 3x8 sharpening stone and honing oil and give them a real lesson.
sal
https://forum.spyderco.com/viewtopic.php?t=78443#p1219379
Re: Tri Angle Stone Diamond 204D vs Cubic Boron Nitride 204CBN
by sal » Mon Mar 19, 2018 3:34 pm
Hi Tjkoko,
Welcome to our forum.
We've been making diamonds for our Sharpmaker since 1981. Even before we had the medium grit stones, we had diamond sleeves. When we could, we made diamond triangles. The problem with diamonds is that they are attached to a steel embryo using a plating process. The diamonds are very hard. Harder than the steel embryo or the plating material that adheres the diamond to the steel. People using the diamonds to sharpen will generally press too hard, which loosens the diamonds from the plated material so longevity is not as desired. Diamonds work best with a very light touch, as the diamonds are much harder than the blade, it doesn't take much pressure to be effective. Getting customers to do this has been very challenging. Most people think (or simply intuit) that "if I press harder, they will cut faster".
CBN has some advantages over diamonds in cutting steel and it is hard enough to sharpen any steel, I felt that if we made our triangles in CBN as well as diamonds, people could try both and in time we might see a difference or advantage to one or the other.
I use CBN and I also use diamonds, but I use a very light touch and take the time to do a careful job not to damage the diamond / CBN. I believe that the CBN might be competitive in that it cuts as well, and I believe adheres better to the plating. Hope that helps?
sal
https://forum.spyderco.com/viewtopic.php?f=2&t=85158&p=1370299&hilit=diamond#p1370299
Re: CBN rods: Corners "different abrasive" from the factory?
by sal » Wed Oct 23, 2019 9:49 am
I generally don't recommend using the diamond or CBN corners for use unless one is very careful to go very slowly and very lightly or you will tear the stones out of the matrix. Most will press much harder than necessary. the nature of a serration is to "wrap" around the corner which is very hard on the matrix.
sal
https://forum.spyderco.com/viewtopic.php?f=2&t=81884&p=1281999&hilit=diamond#p1281999
Re: Double stuff 2?
by sal » Mon Nov 12, 2018 2:51 pm
Hi Spackla,
Welcome to our forum.
The CBN is plated onto steel embryo with a nickle alloy plating. The CBN shouldn't wear much, unless you are pressing too hard. It doesn't take much pressure for the CBN to cut the steel. Many people think that if you press harder, it cuts faster, but that isn't so. Pressing harder just dislodges the CBN stone from the matrix. So it isn't a wear problem but a pressure problem that "wears" diamond and CBN stones.
sal
https://www.bladeforums.com/threads...ride-how-much-pressure.1577615/#post-18059151
I've used 5-10 grams on my harbor freight diamond block with the tip of a knife and didn't scrape anything off that I could see.
I've also used ... 2-3 pounds (? definitely more than 1, unsure, accident ) with a tip and scraped everything to bare steel (nickel+diamonds gone).
Think about that
2lbf/square mm to pounds/square inch = 1290 psi compared to
5 grams/square mm to pounds/square inch = ~7psi
Make it a more dull tip
2mmx2mm = 322psi
If your edge bevel is
2mm wide, .5lb on a 2inch stone is about 3psi.
half inch is 12psi and
quarter inch is 25 psi
If you
use lube (water) and keep the force under 1/2 lb (or 226.8 grams ) cbn/diamond stones should last forever
see
CBN Rods - Page 7 - Spyderco Forums
Diamond rods inferior to CBN rods? - Spyderco Forums
update: a quote
light force, 1/2 lbs but small contact area meant the pressure was high 10-20 psi this translates to 226.8 grams , this is on the flats not the corners of triangles