Cubic Boron Nitride -- C.B.N.

[bobl]

Jesus what have I done. Opened a can of worms here. Sorry.
Let me start by saying " I love my Tormek T7 and the standard wheel ".
One of my other machines I have used for 10 years is By and english company called
The machine is for knife sharpening only and the 2 i use is first and mainly the , with a 126 grit,  the other is a smaller version, theWith a 107 grit and slightly slower revolutions.
They both use C.B.N. coated wheels. However, I only get to sharpen about 200 knives before they need re-plating at a cost of £175 sterling. It lasts me a month. as opposed to the advertised " over 2000 knives before needing replaced or re-plated. THAT IS THE REALITY from my experience.
My question is "is that because the machines I have turn very fast and wear quickly because of it?
Would a C.B.N. coated wheel for the T7 , turning slower last longer?
Yes they are both fast. I will spend a third of time less on these machines than on the T7 for the same amount of knives, but the replacement cost is high and often.

In reply to some questions.
There are no sparks.
You definitely dont need the water trough.
Although a magnet would be handy to collect steel particles coming off the blades. The machines have a magnet built in.
I have used these machines withought the front guard on and just wiped the area away of steel particles.
I would need to try out the C.B.N. wheel for the Tormek T7 to see how it compares. I would be willing to throw some money at it to see if it works. However, at the moment I am more than happy as a Knife Grinding Business using my Tormek T7 and investing more of my time, than using my old machine by with C.B.N. wheels to do them quickly.
I would say that I use my Tormek 70 percent of the time now and my C.B.N. interlocking wheels on the  about 30 percent.
I am open to try the C.B.N. wheel on the tormek.
I will see how much it costs and try it out.
Remember, I am NOT a woodturner or a professional sharpener. I am purely a Knife Sharpener. ( Although I do a few other easy bits, ie axes chisels, scissors etc. )
Thanks for reading.
Cheers .
Bob
P.S.
I love my Tormek T7   

[grepper]

Bob,  Thanks for opening the can o' CBN worms!  I've learned a lot and it has been a very interesting post.  Please feel free to open more cans of worms.

[Rob]

+1  You've done nothing wrong Bob :-)  The debate was interesting and informative about a technology that many of us (me) know little about so it's useful.  But bear in mind that with knife sharpening we don't encounter the same problems as with large surface area very hard alloys.  Even my global knives sharpen quickly on the Tormek and I understand they're very hard steel.  The issue with hard steels is related to planar knives in particular.

As a tip, I would avoid taking the Lord's name in vain too....you'll have Elden on you like a ton of bricks otherwise :-)

[Ken S]

Bob, I agree with Grepper that this is an interesting topic. I'm glad you opened it. I also would agree with Rob's tip. As has been posted earlier, this forum tends to be older and perhaps more conservative socially.

I have never sharpened knives in or for a restaurant. That said, I would think the wet grind operation of the Tormek would be preferable anywhere near where food is prepared. Even if no abrasives from the wheel are dispersed, there are better ways to get the iron we require in our diet.

Grinding speed is another question of balance. We can go fast. We can go slower, with more control. For most work, I would prefer to go a bit slower and have more control. (I am not talking about spending hours with a planer blade.)

Ken

[grepper]

Global knives aren't all that hard.  HRC 56-58.  The Tormek seems to do OK with that.  Try sharpening Shun VG10 and SG2 or some of the old Case knives with HRC 60+.  It will probably remind you of sharpening your planer blades!

[Rob]

Global knives aren't all that hard.  HRC 56-58.  The Tormek seems to do OK with that.  Try sharpening Shun VG10 and SG2 or some of the old Case knives with HRC 60+.  It will probably remind you of sharpening your planer blades!

I'll pass thanks...too scarred by the planar knives :-)  In fact I think I'm going to institute a ban on any steel with Rockwell numbers over 3 in my workshop!!!!

Exotic Alloy??....Shmalloy!!

[Stickan]

Hi,
I do sharpen a lot of knifes, it´s my favourite thing to sharpen, and there is only one steel that I found difficult to sharpen, amorphous metal alloy, witch actually can be discussed if it´s a steel.
VG10 is no problem with the regular SG-250 stone, I recently sharpened several VG10 steel knifes in Atlanta, at the Blade show. 62HRC is fine but when it starts to be a larger surface, like a planer blade, it takes longer.How much surface you sharpen is a factor, on a knife there is a small surface to sharpen on so you will get a good result within a short time.

Regards,
Stig

[grepper]

That's interesting Stig.  For example, I remember I had an old Case XX knife.  I ground away and ground away at that that thing and it was amazingly impervious to the wheel.  I thought that was odd, being an old knife and probably not some exotic alloy.  It was fairly early in my Tormek experience so maybe I didn't apply enough pressure or the wheel was not rough enough, or maybe I was missing the edge, but I spent a long time at it.  It didn't remove hardly any steel, and was oddly frustrating.  I've had the same experience with a few other really hard knives.

I finally got it sharp with a Zirc belt on a belt grinder and even that took a lot of pressure.

I certainly don't want to say something not true to the facts.  If you say that HRC 62 is fine then I'll guess it must have been my technique or I just didn't spend enough time at it.  I'd like to try again.

[grepper]

BTW, does anyone have any experience actually using amorphous metal alloy knives?  Does the edge durability really live up to the hype?
http://vmatter.com/

Lots of $$$$ to try it out.

[Stickan]

I do have one Vmatter and thinks it a good knife. Takes me longer to sharpen than a regular knife as the metal "stretches" and needs a different approach when sharpening.
The idea is that the edge will last longer and as for now I must say it does, in my own opinion. 
Best,
Stig

[grepper]

Wow!  You actually have one!  Which one?

Is it really self-sharpening like some of the hype?
What is your "different approach" when sharpening?
Can you get it as sharp as say a carbon steel blade?

I take it you actually have had to sharpen it... It got dull?  How much abuse did it take to dull it?

Do you prefer to use it over "regular" steel knives?

I'm in the market for a new 4"-5" paring/utility knife... hence all the questions.  These seem to be about the only really new innovation in knife technology in a very long time.

[Herman Trivilino]

It was fairly early in my Tormek experience so maybe I didn't apply enough pressure or the wheel was not rough enough, or maybe I was missing the edge, but I spent a long time at it.  It didn't remove hardly any steel, and was oddly frustrating.  I've had the same experience with a few other really hard knives.

I've had hauntingly similar experiences. One possible explanation is a clogged grindstone, and when we're newbies we don't know it and so can't correct for it. It was these kinds of experiences that led me to use first a magnifier and then a 40X microscope. When these frustrations occur all you can do is continue to blindly grind away, or use a magnifier to see just what in the heck is actually happening to the edge. Usually I find that I'm grinding at an angle that's smaller than the existing one, and so it takes a long time to grind all the way to the edge. This problem is made worse when the steel is hard, the grindstone is clogged or is not coarse enough, or both.

[Stickan]

Grepper,

I have the 8" chef knife with a wooden handle. I have sharpened it 3 times, using the SG and the SB stone.
I did not need to sharpen it but I had to try 
The first thing I noticed was that it takes a long time to sharpen it as it feels like the Amorphous metal is streching. I tried both light and hard pressure and combined I got a new edge one it. Have not had any need to sharpen it again, this was about a year ago.
I do have other knifes that are sharper but they need to be taken care of about every second month now that I got the right angle on them that works in our house.

Stig

[grepper]

Wow, you sprung for the wooden handle.  It is a pretty thing!  I really like the blade shape.

I wonder if your other knives are sharper because it is so difficult to sharpen? 

The thing that I notice is that right after sharpening blades are exquisitely sharp, but that "perfect" sharpness soon is gone.  They are still sharp, but won't hang on the thumb nail quite as well for example.  Just slightly less sharp.  That slightly less sharp hangs in there for a long time, but I'd like to find something maintains that just sharpened, super sharp longer.

That being said, I enjoy sharpening and go through the knife drawer every so often just because I'm in need of a sharpening fix.

I'm intrigued because amorphous metal seems to be the first really significant new development in steel in the last 60 years and it appears to be actually different than just mixing in another alloy.  And oooo...  NASA technology!...  I'm always leery when I see advertisers resorting to that in the description. 

Thanks for the feedback on that Stig.  There are almost NO reviews on line and some are less favorable than I would have expected.

https://www.facebook.com/551390404898925/videos/vb.551390404898925/10151946601060210/?type=2&theater

https://www.youtube.com/watch?v=_51frrQzCYM

http://www.amazon.com/VMatter-Santoku-Knife-Professional-Jade/dp/B00JKTJXDW/ref=sr_1_2/178-9180560-5133633?ie=UTF8&qid=1434538236&sr=8-2&keywords=vmatter

That one about cracking makes me wonder if they suffer the same problems as ceramic knives.

For the same price you could get a Twin Cermax, ZDP-189/M66 steel HRC 66.  I've been trying to talk myself into this one for a couple of years now:
http://www.amazon.com/HENCKELS-Cermax-5-Inch-Utility-30860-130/dp/B0007WTB92

Or a

FC61 steel RHC 61 Bob Kramer Euro Essential:
http://www.surlatable.com/product/PRO-1551555/Bob+Kramer+Essential+Collection+Utility+Knife

Or EIGHT of these. (What I'll probably end up with out of frustration).   I already have one of these.  It's ok.  Nothing to write home about, but it's really ok.  Holds sharpness ok.  Very light weight... if you like that.  Thin blade.  Not a bad handle. Kind of an oddly shaped blade IMHO. Hard to go wrong for $20.00  For $20.00 it's a good deal.

Victorinox Fibrox 5":
http://www.amazon.com/Victorinox-5-Inch-Mini-Chefs-Fibrox-Handle/dp/B000QCLEFC

[Herman Trivilino]

The thing that I notice is that right after sharpening blades are exquisitely sharp, but that "perfect" sharpness soon is gone.

Is this phenomenon more pronounced with softer steels? I suspect it's due to a remnant of the burr. After the burr is removed there's still a remnant of it there, like a set of saw teeth at the microscopic level. Those teeth are quickly removed when the knife is used, leaving behind a more blunt surface.

Perhaps the SJ grindstone is the solution to this problem?

That being said, I enjoy sharpening and go through the knife drawer every so often just because I'm in need of a sharpening fix.

That sounds like an addiction, Mark. That fine piece of Tormek machinery is just sitting there and calls out to be used! 

Victorinox Fibrox 5":
http://www.amazon.com/Victorinox-5-Inch-Mini-Chefs-Fibrox-Handle/dp/B000QCLEFC

If I had an open slot in my knife holder this is what I'd purchase. I have the same knife but with a longer blade. I like it a lot. Easy to sharpen on the Tormek and it keeps its edge a long time. Very thin blade. The factory edge is superb.