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If I was beginning with the Tormek, after the SG which comes with the Tormek, my next wheel would be the 360 grit diamond wheel.  I would skip CBN.
Ken

It would be good to have a comparison of CBN and diamond wheels on the Tormek.  My $180 CBN wheels (10") seem to work very nicely wet and dry on my T8.  I have been waiting for diamond wheels to come back into supply, but now I am not so sure that I will be keen to plunk down ~$330 each for the Tormek diamond wheels. (I don't need the flat sides.)  All of which is to say, with cost as a factor, the performance comparison would be useful.

Gord

I would be surprised if there is much difference at all between the two, and I'd be even more surprised if what small difference there might be could justify the diamond wheels costing twice as much. I've used CBN and diamond in hand sharpening super steels for years and could not notice any significant advantage of one over the other in low-speed applications. Where there are vast performance differences is when you're talking high-speed and high-heat applications.

Thank you both for your responses!

While I appreciate the included formulas, I do ministry, not math (for a reason)! 

The reason I ask is that I just purchased the T-4 and I'm looking at diamond and CBN wheel options. CBN wheels that do not include the CBN coating on the side of the wheel are a third of the cost of the ones that have this option. With CBN or diamond on the sides of the wheel I could sharpen a knife with an entirely flat bevel, but if the 8-inch wheel doesn't create much of hollow grind, then I could get by with the cheaper wheels.

My Google-Fu is failing me today. Has anyone seen a chart that reflects how concave a knife edge is with the 8 and 10-inch wheels? I understand this will vary based on the length/width of the bevel, so let's assume we're just talking about the final beveled edge of a full flat ground blade that would normally be 2-4 mm.

Thanks.

As a person also looking into purchasing a T-4, I have to ask, why does the commentator say that the T-4 is fine for kitchen cutlery, but not bigger knives? Kitchen knives are three times the size of my folding knife collection. What knives are "larger" than kitchen knives other than a machete or something crazy?

Jason,

You might want to look into the use of CBN wheels on Tormeks.  I am not a grinding expert, but remember reading that CBN was designed for the machining industry where high pressures and temperatures were required.  Diamonds won't fit this bill, so CBN is a better alternative.

I would bet that CBN doesn't work well at lower speeds.

Kind regards,
Rich

Thank you for your response, Rich. You and the other members here are a tremendous resource to the community.

I got the idea for using CBN wheels after watching wootz/knifegrinders videos where he uses the CBN wheels and the Tormek for his commercial sharpening operation and produces amazingly sharp knives with them. And, also, from personally using CBN rods on a Spyderco Sharpmaker, which is the slowest of all speeds as it's hand operated.

As others have mentioned, I think the idea that CBN gets gummed up from high carbon steels comes from untempered or incorrectly tempered metal which isn't the kind of steel I own in my high-end folding knives. But, if there's anything I've learned over my blessed long life, it's that I always have more to learn.

This is a common caveat with CBN and diamond wheels, the concern being that some (merely) high carbon steels are not inherently hard enough or haven't been hardened enough, with the result that they could clog ("gum up") the abrasive array on the surface of the wheels. 

However, I don't find the term "high carbon steel" very useful in this context.  It is true that CBN and diamond wheels excel on high speed steels and the newer super hard steel alloys, which pose no risk of clogging the wheels. But some high carbon tool steels can be quite hard and users report that they do not harm their CBN wheels.

Also, some who have experienced clogging have found that the wheels can be cleaned up by grinding some high speed steel on them.

But as Ken is wont to remind us, the standard Tormek grindstone is excellent at high carbon steel, so you don't need to put your exotic wheels at risk.

Gord

Thank you for this response. I have an ever-increasing collection of knives that include high-carbon and stainless steels that include 52100, HAP 40, REX 45, D2, M390, S30V, S90V, S110V, CTS-204P, CV20, and others I don't remember at the moment. I've sharpened these with CBN rods and stones without any damage to the sharpening medium so thought it might be something unique to the Tormek CBN wheels. I know that CBN and diamond are sensitive to pressure and heat (though heat is less of a factor with CBN) so I'm careful to avoid both when sharpening these steels.

I'm in the "research" phase of my Tormek purchase and wanted to make sure I didn't buy something in error.

Thank you again.

I cannot see how this could be done, the honing wheels have a function in the drivetrains of the machines, so they are one-grinding-wheel machines.

Gord

Thank you GKC!

Well to ask more accurately, can I run a CBN wheel on both sides of the T-8 or T-4 instead of the leather honing wheel on one side?

Thank you for answering my newbie questions.

4. Unlike CBN wheels, these can be used for sharpening high carbon steels.

Why do you say that CBN cannot be used with high carbon steels?

<Apparently, I hit the quote button instead of the modify one when attempting to edit my post. Please ignore/delete this post. >

https://youtu.be/Pyb2lOYhNqw

Enjoy.

Ken

Sure wish he would have shown knives being sharpened as he's done in the past with his reviews.

And as far as the diamond wheels go, I'd love to see the scratch pattern of the 1200 diamond stone. I'm thinking the 600 & 1200, and possibly the leather for a final hone are all a person would need for a lifetime of sharpening high-end pocket knives. (All of my knives are high-strength, high-carbide, and stainless super steels)

This is the only one I'm going to tackle...

Where can I find the 1000 grit mesh plate if that's what that is?

That is just a cheap diamond plate, you can get them at Harbor Freight or Amazon for around $3-$4.  Looks like he used double-sided tape or some other adhesive to attach it to the jig.

Advanced Machinery will customize the purchasing experience.  Use this link :

                     https://advanced-machinery.myshopify.com/pages/tormek-home

and then take the option to "Create Your Own Tormek Custom Package" or "Create a T-8 Stripped Package".

Kind regards,
Rich

Thank you, Rich!

Part of the issue may be the cheap knife itself. Some of the "steels" used in the ultra-cheap cutlery sold in big-box discount stores barely qualify as pot metal. Their tempering process can be so incredibly inconsistent that producing good results with your sharpener may just end up producing frustration rather than sharp edges.

It's kind of like learning to play the guitar; most people that are given (or purchase) a cheap starter guitar never end up learning to play it.  The quality is so low that it won't hold its tune and they get frustrated, thinking they can't learn the proper techniques when all they really needed was a nicer mid-level instrument.

I'm not saying you should practice on a $1,000 custom folder, but maybe pick out one of your wife's better kitchen knives that she uses less than the others and practice on it. If you ruin it (though I don't see how), then you'll have an excuse to buy new knives!

Also, there may be two other factors. Someone already mentioned the limitations of the Tormek clamp/jig. This characteristic is due to the knife not being perfectly centered in the clamp. You can check and adjust this by using tape or some other media on the blade to even it up. The second factor is getting the knife in the exact same spot on the stone when you go side to side. You can use a flat plate jig, laser line, or some other contraption to assist your aim.

Where/how can I purchase just the T-8 unit without any stones, jigs, and other paraphernalia?

Thank you!