CBN Wheels

[tony tomlinson]

A fellow at our Woodturners Club meeting the other night shared that by using his new D-Way CBN wheel he is able to effectively sharpen carbide heads - anyone had similar experience?

Thanks all

[Jeffrey J Smith]

Tony: Dave discusses touching up carbide cutters at the end of this video - about 17:10 if you want to go right to it. http://www.youtube.com/watch?v=XdF9mmJtuvU&feature=youtu.be

He does say that you don't want to be doing any heavy shaping of carbide, but touch up sharpening is okay. As I understand it, carbide is best shaped on diamond wheels. CBN is designed for HSS.

[Thom Sturgill]

According to Cindy Drozda's blog, the new Powder Metal tools contain carbides that the AO wheels do not sharpen. Diamond or CBN is required because of the carbides. As Jeffery says - Dave at D-Way says you can touch them up, just don't do production sharpening on one.

[Matt Mackinnon]

I am reaching back quite a few years to my collage days. But part of my mechanical engineering classes we had metal shop. I was given a chunk of carbide and had to grind it into a toolbit to turn a set of step pulleys out of carbon steel. So I don't see why anyone would say that AO wheels don't sharpen PM because of the carbide content. Wood can chip carbide, but not real efficiently and that is why they don't make grinding wheels out of wood. an AO wheel can grind carbide, maybe not as efficiently as diamond wheel. but a heck of a site more efficient than wood.

it's unfortunate that Cindy's words were not in some form of context. Perhaps she was saying that they can't be sharpened as fast or as easily as a CBN wheel, but they sure can be sharpend on an AO.

Matt.

[Thom Sturgill]

The link to Cindy's blog was posted here just recently in another thread, but its http://www.cindydrozda.blogspot.com/ What she claimed was that the micro-fine crystal structure of powder metals contain carbides which get knocked out of the steel matrix rather than cut because they are harder than the AO wheel.

I do know that before buying a CBN wheel I had to hone with a diamond hone to get my PM tools as sharp as my M2 or M42 tools, but once I did the edge stayed sharp longer. With the CBN wheel I have found honing less needed and that seems to verify what she was saying.

[Harry Robinette]

I don't know much about CBN wheels but everyone and everything I've read says don't use them for carbide or mild steel, I'm not sure about just honing carbide on them.

[Matt Mackinnon]

The link to Cindy's blog was posted here just recently in another thread, but its http://www.cindydrozda.blogspot.com/ What she claimed was that the micro-fine crystal structure of powder metals contain carbides which get knocked out of the steel matrix rather than cut because they are harder than the AO wheel.

I do know that before buying a CBN wheel I had to hone with a diamond hone to get my PM tools as sharp as my M2 or M42 tools, but once I did the edge stayed sharp longer. With the CBN wheel I have found honing less needed and that seems to verify what she was saying.

Thanks for the clarification. I see where she is coming from in her assessment. I did take some time to look more into this and several of the manufacturer mills are also saying the a CBN grinding or SG wheel will give the best results. But based on the mohs' hardness chart, the carbide and aliminum oxide are around the same hardness (9). Given that the cubic boron nitride is harder (10) and processed correctly is actually harder than a diamond, I can see why it's recommended. I don't know about the molecular bond of the carbide and if in grinding it will break before fracturing, I guess a scientist will have to answer. Very interesting non the less.

Will have to think about getting a CBN wheel as I have some PM tools on order. I am looking into a Canadian supplier in Ottawa for those of us north of the border who may be looking to get one and dont want to deal with brokerage, duty and all that junk.

[Paul Gilbert]

I had the same question so I emailed Dave. His reply: "Yes, you can touch up carbide, my CBN hand hone does a good job also.

[Reed Gray]

Cutter Master, is the brand in Canada, and they have adds in the AAW magazine. It is a nice wheel, but only 1 inch wide, with a side grind, and it is the heaviest of the wheels at 8 pounds. I really do love the extra width. Oh yea, they have a really nice grinder, on the expensive side, but DC motor variable speed.

robo hippy