CBN Grinding Wheels

Thanks jbolt for the reply regarding material removal. Can I ask about heat in the tool. More often then not I ll get some chipper knifes that have been hand ground with a hand grinder and alot of shape work to bring back to the recommended angle. There 5/8 thick and take some time. For now I rough it on a variable speed grinder at around 2200 rpm but have to be carefull with heating the blade and do it in stages and let it sit even with dunking and come back to,it before I finish it on the Tormek wet grinder. It would be great to be able to run the grinder ar it s 3600 rpm and remove the material without worrying about ruining the temper. The material a8m isn t hardened fully around 40 on the r c scale. A pain to grind as it clogs the wheel. Using a white aluminum oxide wheel how would you compare the cbn in this regard? Also is dust reduced as well with the cbn?
Mark, If the steel you use clogs your ceramic wheels, it will be an issue for the CBN.

It will likely clog the CBN and that can ruin the wheel. With a ceramic wheel you can level/grade it again if it gets clogged. With a CBN wheel the CBN is a coating so you have toasted it if you clog it badly.

CBN likes the hardness of RC54 steels and above. Here's a link that talks to that issue and defines the use of CBN and materials you should machine with it.
 
What I Was referring to when run at 3600 was the heat. Right now around 2200 is where I Limit the speed due to heating of the a8m chipper knife too much. The grinder and wheels are very smooth. It s a hardened tool steel just not as much as normal. I may take a chance and try one.
 
Thanks jbolt for the reply regarding material removal. Can I ask about heat in the tool. More often then not I ll get some chipper knifes that have been hand ground with a hand grinder and alot of shape work to bring back to the recommended angle. There 5/8 thick and take some time. For now I rough it on a variable speed grinder at around 2200 rpm but have to be carefull with heating the blade and do it in stages and let it sit even with dunking and come back to,it before I finish it on the Tormek wet grinder. It would be great to be able to run the grinder ar it s 3600 rpm and remove the material without worrying about ruining the temper. The material a8m isn t hardened fully around 40 on the r c scale. A pain to grind as it clogs the wheel. Using a white aluminum oxide wheel how would you compare the cbn in this regard? Also is dust reduced as well with the cbn?

All I have ground so far is tool steel lathe bits, drill bits, a bunch of old abused wood chisels and cleaned up the end of a cut bolt or screw. Compared to the AO wheels the heat generated and grinding time is significantly reduced.

As far as"dust" is concerned the only residue is the removed material. Also I'm not getting any debris buildup in/on the guards like with the AO wheels.

I can't comment on the steel your using since I have no experience with it on these wheels.
 
Thanks jbolt. I think i am going to try one when the funds permit.
 
I would think the nylon center defeats the heat sinking that the aluminum hub does. There by creating a new issue (HEAT) which you didn't experience.
 
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