Hand Tools

Subject:
CBN and grit
Response To:
My thoughts ()

Patrick Chase
Derek's suggestion of using 180# CBN wheels brings up a key difference between CBN and traditional wheels.

When you grind a piece of metal, there are two major sources of heating:

1. Heat dissipated due to deformation of the metal that is removed. To a rough first order this is proportional to the total volume of metal removed.

2. Surface friction between the abrasive and the workpiece. To a rough first order this is proportional to the number of revolutions the grinding wheel takes to get the job done, and inversely proportional to the sharpness of the abrasive.

Fine grit wheels require more revolutions/passes to remove a given amount of material and therefore dissipate more heat into the tool from friction. That's why you generally want to do major material removal using coarse grits with conventional (AlOx) wheels.

CBN crystals are sharper and cut more easily than AlOx grains (especially worn ones) and vastly reduce frictional heating. That in turn means that the "heat penalty" of finer grit wheels is greatly reduced, and you can get away with doing significant grinding on 180# or 220#.

As to the amount by which CBN reduces heating, I've seen one study showing a 4X reduction, though I can't remember what grit # it was for. Deformation heating is relatively constant, so obviously CBN does best compared to conventional wheels when friction dominates, i.e. at finer grits.

Messages In This Thread

flattening Waterstones- shapton pro
Re: flattening Waterstones- shapton pro
Re: flattening Waterstones- shapton pro
Re: flattening Waterstones- shapton pro
Re: flattening Waterstones- shapton pro
Flattening
Revise atoma price...
Re: Revise dia-sharp price...
Diamond plates
Re: Diamond plates
Diamond plates......
Re: diasharp vs. diaflat
Re: diasharp vs. diaflat
Re: I think...
Re: I think...
Re: flattening Waterstones- shapton pro
Yes, this
lapping film?
Re: lapping film?
Re: lapping film?
you are not kidding!
Re: lapping film?
A different perspective *LINK*
Re: A different perspective
Not universal preference
to date
Re: to date
Re: to date
Re: to date
Re: to date
:) *NM*
Re: to date
Re: A different perspective
My Opinion...
Re: My Opinion...
My thoughts
Re: My thoughts
Re: My thoughts
The flat wheel surface - or not..
Re: The flat wheel surface - or not..
Re: The flat wheel surface - or not..
Re: The flat wheel surface - or not..
CBN and grit
How Are You Cleaning The CBN Wheel . . .
Re: How Are You Cleaning The CBN Wheel . . .
Re: How Are You Cleaning The CBN Wheel . . .
Why grind unhardened steel on CBN?
Re: Why grind unhardened steel on CBN?
Re: How Are You Cleaning The CBN Wheel . . .
Re: A different perspective
Re: flattening Waterstones- shapton pro
Quick and dirty summary:
Re: Quick and dirty summary:
Atoma - $64
Re: Atoma - $64
Sandpaper Flattening & Shaptons
Re: Sandpaper Flattening & Shaptons
Re: Sandpaper Flattening & Shaptons
Re: Sandpaper Flattening & Shaptons
Stearate coating
Re: Stearate coating
Re: Stearate coating
Re: Stearate coating
Plastic laminating sheet
Re: Stearate coating
which side to use?
Re: which side to use?
Re: which side to use?
Re: which side to use?
a little bit the Indian and a little bit arrow
Re: a little bit the Indian and a little bit arrow
What a great thread this has been.....
Re: What a great thread this has been.....
Re: What a great thread this has been.....
Re: What a great thread this has been.....
Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method *LINK* *PIC*
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
My apologies for being a bit too harsh..
Re: Washita vs soft Arkansas stones...
Re: Washita vs soft Arkansas stones...
Re: Washita vs soft Arkansas stones...
Re: Washita vs soft Arkansas stones...
well then....
Another possibility presents itself......
CBN plates
Re: Not making sense..
Diamond wear
Re: Diamond wear
Re: Diamond wear
Re: Diamond wear
Re: Not making sense..
Re: Not making sense..
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