CBN wheel vs various types of steel

[Lasse Hilbrandt]

On a Facebook group I'm a member of dedicated to chisels there is a guy who claims that using a CBN wheel on high carbon steel is a bad idea because it will gum up the wheel making it useless for HSS.
I'm thinking of getting a CBN wheel to establish the primary bevel on plane blades and chisels but I was going to use it for all my steels.
Is he right or is it nonsense?

[Vincent Tai]

Nonsense. Unless the high carbon is soft and you are really pushing into the wheel. And there is no point in pushing hardened HC steel very aggressively into any wheel unless it is very water cooled. I grind enough high carbon to collect the dust and set aside for many uses. I've ground quite a few new HC steel tools from zero bevel to 25-30 degree. An 80 grit wheel would be rather hard to clog with anything and normal pressure. High up on my list of things to get. A Japanese HC steel being ground in pic below.
IMG_1506.jpg

[Tom M King]

There are statements that they are not intended for low carbon steel. I think they must be talking about steel that approaches wrought iron in carbon content. Almost all my cutters are 01, with some W1's thrown in, and some HSS cutters. My CBN wheel has been used way more than almost any hobbyist would use one, for several years, and it has never shown any signs of "gumming", or clogging.

I've never heard the claim that it was not good for HSS, but would like to see real evidence. I never shape tools completely from the beginning with one though, but can see where it should be easily possible.

[Frederick Skelly]

I've read the same warning statements that Tom mentioned.

But recently, there was a post by one of our woodturners refuting that - someone who's pretty knowledgable on CBN (it might have been Robohippy). I think there were also words about how to "unclog" gthe CBN too - something like you need to grind some harder steel after the softer? I can't recall. Maybe one of the turners can chime in with more on this.

[Lasse Hilbrandt]

Ok I think there is nothing to be "afraid of then"

[John K Jordan]

I've read the same warning statements that Tom mentioned.

But recently, there was a post by one of our woodturners refuting that - someone who's pretty knowledgable on CBN (it might have been Robohippy). I think there were also words about how to "unclog" gthe CBN too - something like you need to grind some harder steel after the softer? I can't recall. Maybe one of the turners can chime in with more on this.

Yes, Robo Reed wrote about this. He tried grinding mild steel on CBN and loaded up the wheel, cleaned it by sharpening a large HSS scraper.

HSS, O1, W1 - the wheels are made for that. I've also ground carbide inserts as a test for a friend. Mild steel, aluminum, brass - not so good. That said, I've ground little mild steel with no detrimental effects. I have no idea about annealed/unhardened tool steel but I'd be cautious.

I keep two separate grinders with AlOx wheels for mild steel. (I use four CBN wheels, mostly for lathe tools)

JKJ

[Derek Cohen]

Just to confirm: CBN wheels are absolutely good for carbon steel. It is only unhardened steel that poses an issue.

Regards from Perth

Derek