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Anyone using CBN wheels on a bench grinder?

Mikel Levy

Aluminum
Joined
Oct 19, 2009
Location
Seattle
There seems to be a lot of information available about using CBN (cubic boron nitride) wheels on a standard bench grinder for refreshing the bevel on woodworking tools, but precious little on using CBN for hand grinding high speed steel lathe bits and such, where a lot of material needs to be removed. Anyone have any experience or knowledge of using CBN for this purpose?

Mike
 
There seems to be a lot of information available about using CBN (cubic boron nitride) wheels on a standard bench grinder for refreshing the bevel on woodworking tools, but precious little on using CBN for hand grinding high speed steel lathe bits and such, where a lot of material needs to be removed. Anyone have any experience or knowledge of using CBN for this purpose?

Mike
The only grinding wheels I use for sharpening my woodturning tools are CBN. I've had members of our machinist group visit my home shop and try out my CBN wheels and ALL have purchased their own within days afterwards to sharpen their HSS lathe and drill bits. I'm a novice machinist and have only begun to sharpen these tools but the advantages I see are; the wheel doesn't need to be dressed, the tool being sharpened tends to remain cooler, longer lasting, cuts just as well if not better and will not disintegrate (I use mine without guards). The initial cost of a CBN wheel is more but they pay off in the long run.

PS I not only refresh the edge of my tools with CBN wheels but establish the initial grind with them. They cut that well.
 
I have three CBN wheels mounted. Use 'em for wood tools (chisels, plane irons, turning tools) and metal cutting tools (HSS, drill sharpening, point splitting, center punches, knives, etc.) and wouldn't go back.

Main difference to Beeser is that I'm too cheap to use them for roughing. They will eventually wear out under pressure and (to me) it's a shame to lose that perfectly square grinding surface. Roughing things like a HSS blank or a mushroomed cold chisel used to get a free cutting abrasive wheel and frequent dunks to keep things cool. These days a belt grinder is more often used, still with cooling as needed.
 
My main grinder in shop has a wheel 14"x3", I wonder what It would cost for a CBN version

Likely a lot more than a decent 6-7" grinder AND a pair of CBN wheels to fit it.

But I'll bite. Assuming that's a monster pedestal grinder and not something like a cylindrical grinder, what are you feeding it?
 
I have three CBN wheels mounted. Use 'em for wood tools (chisels, plane irons, turning tools) and metal cutting tools (HSS, drill sharpening, point splitting, center punches, knives, etc.) and wouldn't go back.

Main difference to Beeser is that I'm too cheap to use them for roughing. They will eventually wear out under pressure and (to me) it's a shame to lose that perfectly square grinding surface. Roughing things like a HSS blank or a mushroomed cold chisel used to get a free cutting abrasive wheel and frequent dunks to keep things cool. These days a belt grinder is more often used, still with cooling as needed.

Roughing a high speed steel blank (typically 3/8" square) to shape would be one of my main uses of the CBN wheel, but you seem to suggest that the life of the wheel under those conditions would be rather limited. I guess there's only one way to find out. Would an 80 grit wheel would be suitable for this task?

Mike
 
Roughing a high speed steel blank (typically 3/8" square) to shape would be one of my main uses of the CBN wheel, but you seem to suggest that the life of the wheel under those conditions would be rather limited. I guess there's only one way to find out. Would an 80 grit wheel would be suitable for this task?

Mike

It would certainly be cheaper.
 
Just like any other operation, heavy stock removal is going to cause more wear to the cutting implement. I run a CBN wheel on my drill grinder, but I use a plain AlO2-wheeled bench grinder for heavy stock removal first also.
 
CBN wheels are great in some/many applications..but they are costly to buy and costly to true-up/dress.

A small diamond wheel mounted in a hand held spindle makes an OK dresser. Yes holding it at angle so it does not spin at high RPM held against the running CBN wheel.
 
Can someone recc a good CBN wheel for a 6"/8" grinder?

Also recommend the grit and the purpose..common often go from 80 to 180 or so it would be good for someone to choose the right grit with not trying a bunch of wheels.

I used CBN wheels on CNC grinders and made up an arbor so I could quickly re-dress them on a motorized head TC grinder using green wheels and diamond wheel for redressing.

They would eat up a green wheel PDQ.
 
Just like any other operation, heavy stock removal is going to cause more wear to the cutting implement. I run a CBN wheel on my drill grinder, but I use a plain AlO2-wheeled bench grinder for heavy stock removal first also.

Same here. Get the rough shape with a run-of-the-mill aluminum oxide wheel, then take it over to the CBN to lap in the geometry.

We have a Baldor tool grinder with CBN on both sides that is nice because of the big angle tables and they tend to run more true, but for basic lathe cutters that it doesn't matter how exact the angle is, a generic bench grinders tool rest works fine for me.

Speed would be the only other thing in that some things work nicer with a slower speed, but most bench grinders are all fixed at their 1725-3400 or so speeds. We have a couple wet stone grinders that come in handy, but I'm also playing with an overhead belt driven grinder at home to use for tool sharpening with he intent of being able to manipulate pulley sizes as needed.
 








 
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