Gritomatic Metallic Bonded CBN Benchstone

DeadboxHero

DeadboxHero

Joined
Mar 22, 2014
Messages
5,364
These have been a work in progress by Konstantin at Gritomatic for the past two years. I had been pestering him to make a CBN benchstone for quite awhile ever since I first saw the Resin CBN edge pro stones made by Poltava and after using a Vitrified Bonded Diamond stone from Japanese Knife imports and being Blown away.

I've had this 1000 grit prototype benchstone for the past several months that I bought from Konstantin to help test the stone and help me cool my burning curiosity about the technology and what role it has in this new world of ultra premium, high performance stones.


The three major bonds for the future of these "Super abrasive" waterstones are Resin(most common, most affordable) Vitrified ( most difficult to make) and Metallic Bonded ( more expensive then resin)

Each of these have different advantages and disadvantages that will be covered in another thread in the future.

None of these bond types with superabrasives are new, They have been used in the grinding wheel industry for several decades


Here is a preview video of the stone.



This will be an in-depth review and tutorial about Metallic Bonded CBN Benchstones that are sold and mounted on glass by Gritomatic, and abrasive stones made by Poltava.

nxedy6u.jpg

Very excited to share my experience in this thread.

Shawn
 
hm7DVGd.jpg


I was greeted by a nicely packaged stone.

492Ug7T.jpg


The stone surface had a brown gray appearance. Very nice fit and finish.

1bWetfy.jpg


At the top of the stone the size of the grit is labeled in microns and the Poltava logo.

14 to 10 microns.

This is the 1000 grit stone from Gritomatic.

PjlOAoG.jpg

I am a HUGE fan of the glass base. It's very tastful, and serves a purpose since it's not reactive to the Ferric chloride acid used to chemically dress the stone.

tSguUTs.jpg


I wasted no time when I first got this stone and immiediatly slapped an edge on my Akifusa Migaki laminated with a powdered stainless SRS 15 core steel at 64 HRC.

The stock dress was interesting. It had a texture to the surface yet was smooth. I have not been able to recreate the factory dress but I've found better dressing methods that increase feedback and cutting speed. (More on that later)

I thought what was also interesting is that the "shiny" spots in the picture above on the stone.These spots look like loading are actually the steel polishing and rubbing the metal bond versus the opposite happening on resin and Vitrified bonded stones. Very interesting.
 
ri4K4Z0.jpg


I had a new factory edge on a s30v Benchmade Proper Slipjoint to.

Factory edges are usually a 120-220 belt and buffed and deburred for a blend of polish and tooth to meet the vast array of users needs and preferances out of box.

bhpOjEq.jpg


I thought it would be interesting to see if this stone had the cutting power to remove factory scratches on the bevel for a clean 1000 grit finish.

w3FpldI.jpg


This stone had no trouble. And left a very bright 1000 grit bevel. The bonding doesn't help polish like on the resin stones so the angles will have to be dead on or alot of swirls and scuffs will be on the bevel.

This stone really came into its own though once I found the dressing that I liked.
 
A burning question... Why CBN over diamond? Do you have a preference?

I've been giving thought to going with a super abrasive stone but on the fence about which ones.
 
That's a great question and can be it's own thread. Often you just get people regurgitating the specifications off a Google search.

So here is the difference.


In practice, your average guy can't tell the difference.

Now someone with your experience Jason will notice the Diamond may shred on the soft cladding of a single bevel knife more and may give a slightly more aggressive cut and edge at similar grit, The CBN is a little more gentle on the cladding and gives a cleaner smoother cut.

It's very subtle though.

To be honest there are so many variables it's difficult to say exactly.

Really its the bonding and how the stone is dressed that is the hidden reason why one stone will behave differently from another.

So I'd be more concerned about bond type then the abrasive type.

But as you're well aware, nothing beats trying the stone.

I know that Sal from Spyderco offers Diamond AND CBN coated triangle stones which always confused people as to which ones to get. His feelings are that the CBN grains are less prone to tearing out since they are more compatible to bond then harder Diamond grains. I've used both and I couldn't tell the difference lol.

There are more experts to ask that have good experience outside of Google knowledge too.

Like M-S-T M-S-T @Diemaker Gritomatic Gritomatic

These guys are subject matter experts on the topic and should have interesting things to say.

Perhaps a new thread or directly message them?

I'd like to keep this thread on the topic of this Metallic Bonded CBN Stone from Gritomatic Gritomatic :D

Jason B. said:
A burning question... Why CBN over diamond? Do you have a preference?

I've been giving thought to going with a super abrasive stone but on the fence about which ones.
Click to expand...
 
Last edited:
Shawn, are there alternatives to dressing with Ferric Chloride? Or must it be done chemically?
 
If you put aside all the CBN benefits in the industrial high-speed applications. The main difference is the form of the crystal. Mono diamond is a tetrahedron and cbn is an octahedron. Therefore there is a difference in the way the abrasive interacts with steel, differences in the scratch pattern. CBN leaves less deep scratches. There are more stuff to it, but that's basically it. And of course, the cbn costs way more than mono diamond. Usually, people love the way cbn removes the steel compared to diamonds. If you can afford it, it is pretty much the bee's knees.
 
Blues said:
Shawn, are there alternatives to dressing with Ferric Chloride? Or must it be done chemically?
Click to expand...

I found in the past several months of testing
The Ferric Chloride is ESSENTIAL for the stones to work properly

In the past, I made a thread about the edge pro sized metallic bonded stones and was using a Green SiC dressing stick to resurface.

That information is wrong.

I'll get into it in another post. lots of details to share over the past several months of testing.

I've developed a way to make the stones perform best through trial and error with ferric chloride, barkeepers friend and raw SiC powder on a porcelain tile.

I'll lay out the system that worked here soon.
 
M-S-T said:
If you put aside all the CBN benefits in the industrial high-speed applications. The main difference is the form of the crystal. Mono diamond is a tetrahedron and cbn is an octahedron. Therefore there is a difference in the way the abrasive interacts with steel, differences in the scratch pattern. CBN leaves less deep scratches. There are more stuff to it, but that's basically it. And of course, the cbn costs way more than mono diamond. Usually, people love the way cbn removes the steel compared to diamonds. If you can afford it, it is pretty much the bee's knees.
Click to expand...
Jason B. Jason B. See?! The expert man :D

Thanks Karolis :D
 
You must log in or register to reply here.
Back
Top