Dressing a vitrified bond CBN wheel?

[Terry Keeley]

Search didn't come up with anything.

I saw Mcgyver's video but it's for resin bond wheels. I see there are "brake dressers" but is there any other way to do it?

 

[CarbideBob]

I have both resin and vit bond CBN and diamond wheels.
A brake or motorized dresser works best.
A far distant second is a molly stick but here you are just trying to wear the wheel away and not removing the bond and making the grains go fly away.
In most cases a vit CBN wheel will kill a single point diamond point very fast.

 

[Terry Keeley]

I have both resin and vit bond CBN and diamond wheels.
A brake or motorized dresser works best.
A far distant second is a molly stick but here you are just trying to wear the wheel away and not removing the bond and making the grains go fly away.
In most cases a vit CBN wheel will kill a single point diamond point very fast.

Thanks, I'm finding some info on dressing with a molybdenum rod.

 

[M. Roberts]

Terry,

I have used both a molly stick and a brake dresser to true diamond wheels with success; although neither would touch the VIT bonded diamond wheels; I use a truing spindle from GII Solutions with a diamond wheel....it works great, but they aren't cheap. I didn't see you mention the diameter of the wheel you are trying to true up; brake dressers are usually good up to a given diameter...

Mark

 

[Terry Keeley]

Terry,

I have used both a molly stick and a brake dresser to true diamond wheels with success; although neither would touch the VIT bonded diamond wheels; I use a truing spindle from GII Solutions with a diamond wheel....it works great, but they aren't cheap. I didn't see you mention the diameter of the wheel you are trying to true up; brake dressers are usually good up to a given diameter...

Mark

Thanks, I just can't justify a brake dresser for my home shop use, I have a piece of Moly coming to try.

It's a small 5/8" diameter, 170 grit CBN wheel for I/D grinding chrome.

 

[michiganbuck]

At the very start, it is good to knock a diamond wheel in to .002 or less run-out. Wet grinding a piece of brass or mild steel with small infeeds can sometimes dress a diamond wheel. A handheld craked mini can sometimes dress a diamond wheel. Having .005 or so run out at the start ->it will be a bugger to dress that much with holky dressing methods.

Having the likes of a tool post grinder you can dry grind a diamond wheel with a hard green wheel, or a hard Black silicon carbide wheel ..but that might take a whole wheel to take just a little off the diamond wheel, I would grind cross-wise (at an angle) trying this.

A piece of Moly held in a v block or vise and traveling across can do a little dressing.
Turn your mounted Diamond wheel in its holder to see if there is a better/more true running turn aet to hold it.

 

[CarbideBob]

Do you have a good soft wheel stick to free it up?
After that dress with moly it will be very dull cutting.

 

[eKretz]

I've never used a vitrified bond diamond or CBN wheel, but since we've got a couple guys replying who I'd find likely to know: can a vitrified bond CBN or diamond wheel be crush dressed?

 

[jbacc]

Would this be an option? About $108.00..

This is what an old time engineer at Darex recommended for the CBN wheel on my E90 End Mill Sharpener. I never bought it and have not dressed the wheel but wonder if it would work...

Object moved

 

[michiganbuck]

QT: [can a CBN or diamond wheel be crush dressed?]
An aluminum oxide wheel that is crushable has a bond that will let loose more easily than in a common wheel...Nany AO wheels might break with trying to crush them., I have tried to crush a common AO wheel and gave up because of thinking the pressure was too high to be safe.

I have not tried to crush a diamond or CBN wheel but I suspect that it could not be done.

I suspect that one could make a break dresser if having a break dresser wheel. the trick would be to assure that the dresser wheel could not be spun fast enough to explode... I don't know what RPM that would be..it may be listed on the wheels. I think it is 8 or 9 thousand RPM

 

[M. Roberts]

MichiganBuck is correct; once the wheel is "trued", it will need to be dressed. Most people use those terms interchangeably, which not correct...Truing is just that...it makes the the wheel run concentric to the spindle/hub assembly, and done correctly, leaves a flat face across the wheel. The truing step will leave bond residue "smeared" into the pores of the wheel; the dressing operation opens up/removes the material from around the grains; exposing them and the sharp edges. I have never heard of anyone using brass (not saying it isn't possible) to true a wheel.

eKretz: I have tried to "crush dressed" a diamond wheel; feeding straight down onto a block of steel...I wasn't really satisfied with the results...I think that it would be better to index the full width of the wheel rather than to plunge.

Take caution when truing diamond wheels..I was taught that truing with either a molly stick, or a brake dresser was done dry...this causes a lot of bad dust...make sure to use a mask and some means of dust collection, even if its just a shop vac with a HEPA filter.

Mark

 

[michiganbuck]

The Desmond cracker jack wheel can be hand pushed against a diamond or CBN wheel at a 45* angle spinning on a bearing shaft, as can be a sacrifice diamond wheel spinning on a bearing.. Dressing this way one alters the dressing wheel angle to make the dressing wheel run slowly. A few hundred RPM is enough, to let the dressing wheel spin/speed up it can blow up.

* As Mark said..a high-quality dust mask is a must .

https://www.mscdirect.com/browse/tn...10e0095ace1312c0a8116b54f0df10eb&gclsrc=3p.ds

Diamonds crashing diamonds can dress a diamond or CBN wheel ..so having a broken or a plate diamond wheel that still has some diamond can sometimes make a Hack dresser.

 

[Terry Keeley]

At the very start, it is good to knock a diamond wheel in to .002 or less run-out. Wet grinding a piece of brass or mild steel with small infeeds can sometimes dress a diamond wheel. A handheld craked mini can sometimes dress a diamond wheel. Having .005 or so run out at the start ->it will be a bugger to dress that much with holky dressing methods.

Having the likes of a tool post grinder you can dry grind a diamond wheel with a hard green wheel, or a hard Black silicon carbide wheel ..but that might take a whole wheel to take just a little off the diamond wheel, I would grind cross-wise (at an angle) trying this.

A piece of Moly held in a v block or vise and traveling across can do a little dressing.
Turn your mounted Diamond wheel in its holder to see if there is a better/more true running turn aet to hold it.

I made an arm that bolts to the side of the base to hold a standard 9/16" diamond nib for truing AO wheels so I was thinking to mount a piece of moly there to try to true up my 170 grit CBN wheel. Grinder is shown here at 1:50: Clausing 8520 spindle grinding. - YouTube

Do you have a good soft wheel stick to free it up?
After that dress with moly it will be very dull cutting.

After truing I was going to clean it up with one of these: https://www.mscdirect.com/product/details/98396070

Are these recommended for vitrified bond wheels as well? I also read somewhere the stick should be finer grit than the wheel?

Would this be an option? About $108.00..

This is what an old time engineer at Darex recommended for the CBN wheel on my E90 End Mill Sharpener. I never bought it and have not dressed the wheel but wonder if it would work...

Object moved

That looks interesting, might work if the moly doesn't. As a side note I was able to true up some badly worn diamond wheels on my Baldor carbide grinder by just repeatedly forcing a piece of cold rolled steel into it. Was slow going but eventually I got the wheels trued up.

 

[Terry Keeley]

The Desmond cracker jack wheel can be hand pushed against a diamond or CBN wheel at a 45* angle spinning on a bearing shaft, as can be a sacrifice diamond wheel spinning on a bearing.. Dressing this way one alters the dressing wheel angle to make the dressing wheel run slowly. A few hundred RPM is enough, to let the dressing wheel spin/speed up it can blow up.

* As Mark said..a high-quality dust mask is a must .

https://www.mscdirect.com/browse/tn...10e0095ace1312c0a8116b54f0df10eb&gclsrc=3p.ds

Diamonds crashing diamonds can dress a diamond or CBN wheel ..so having a broken or a plate diamond wheel that still has some diamond can sometimes make a Hack dresser.

Looks similar to jbacc's link in post #9 (except hand held of course): Desmond - Grinding Wheel Dressers - Crackerjack Dressers

 

[CarbideBob]

See the last picture in post#8 here for my low dollar method.
Brake Controlled Truing Wheels
Bob

 

[ballen]

Hi Bob,

See the last picture in post#8 here for my low dollar method.
Brake Controlled Truing Wheels

thanks for the link and photo, that's very interesting.

I've done all of my grinding with AO wheels, and never dressed with anything other than a single point or cluster diamond.

What's the use case for these kinds of "rotating wheel" dressers? Why are they called "brake dressers"? Are they only for diamond and CBN wheels or also for SiC or AO ones? Are there some standard rule of thumb about the size/speed/materials for the dressing wheels? Motor driven versus free wheeling? What rpms or surface speeds are appropriate?

Sorry for all of the questions, but I'm intrigued by this. Apart from trying it myself, the only way I can learn is by reading about it here.

Cheers,
Bruce

PS: found this: DIY Diamond Wheel Dresser - YouTube

 

[sfriedberg]

Since this discussion has widened a bit, let me ask about boron nitride and aluminum oxide dressing sticks. The BN sticks are hard as hell, and sometimes have extremely large grain structure, while the AlO sticks are usually very fine (600 grit) and a relatively soft bond for their density. Are the BN sticks actually for trueing/shaping rather than dressing? When is it appropriate to use one or the other?

 

[michiganbuck]

Norbide stick are mostly for dressing AO wheels.. and they dress green wheels.
They don't dress a diamond wheel.
We would diamond grind a Norbide stick to become a dresser shaped to a certain radius, just as they come they would dress flat and angles to an AO wheel.
I would lay a Norbide sick on the SG mag chuck (blocked in) and grind with long travel only to put on a 120 or 220 grit pattern so to be used as a deburring device, and to put the last tickle on a knife sharpening, it acted like an almost diamond-hard file..
norbide dressing stick - Bing

 

[eKretz]

Yeah, BC or Norbide is good for shaping a wheel quick, and saves on diamond dresser wear. It can do an okay job at dressing sometimes too, especially useful on something like a tool and cutter grinder with an AlOx or SiC wheel. Won't work on a diamond wheel for dressing, not sure about opening the structure. Would rather waste a cheap Alox stick for that. Norbides are expensive these days.

Edit: Buck beat me to it.

 

[eKretz]

After seeing your comment about Boron Nitride I had to go take a look. I had always thought Norbide sticks were Boron Carbide. Turns out they have both! And both are called Norbide! Sheesh. Wonder which ones I've got. No way to tell as far as I can see. Both types are listed here under dressing sticks. Look pretty darn identical as far as I can see.

Dressing Sticks | Norton Abrasives