How do you reshape your diamond wheels?

[ESjaavik]

I just discovered we have some people here that knows how to grind more than their teeth! I have a question for you:

How do you reshape a diamond wheel?
I have some diamond wheels that lost their original edge, and one that is not running true. If they were corund wheels, some would need a touch of a diamond, and one would need more than a touch to get back the edge. By edge, I mean shape, not just cutting properties.

But I cannot do that with a diamond wheel, or...?

[HuFlungDung]

Good question and I don't know the real answer.

I have had a measrure of success dressing a diamond (or also CBN) wheel with just a soft mild steel rod for a dresser. The trick seems to be that you cannot run the wheel at full rpm. For me, this meant just leaving the wheel mounted, starting the grinder up, then disconnecting the power and pressing the steel against it (and pressing quite firmly) and bringing the wheel to a fairly quick stop while traversing the face somewhat. All you can hope to do is attempt to crush the bond of the wheel and make a few of the dull diamonds drop out.

Perhaps you could rig up some kind of roll crusher to do this job if you have a really mishapen wheel, although the diamond layer is not likely to be all that thick.

[ViperTX]

Well since diamond wheels only have a coating of diamonds that is next to skin deep....you really should measure the amount of crown...I think that you'll find out that if you flatten the crown you'll really getting rid of your sintered diamonds. So, the best measure is to use the diamond surface evenly over their life time and continue using the existing diamond wheels crown.

[ESjaavik]

I did not mention that, but the wheels in question are not the plated kind, they have a ring of what seems to be a mix of binder and diamond particles. One is supposed to have a sharp edge, that now is quite dull. But there are still diamond particles visible.

[keithorr]

I true diamond wheels for grinding glass by using SiC dressing stones. The kind you would use to hone a knife. To remove high spots, I cut into the flat of a SiC brick so there is full contact for about a sixth of the wheels circumference. Coming to a full stop with consistent contact pressure is also part of the dressing process. The SiC works to flatten the face and true an out of round wheel. It can take about 5 minutes of farting around to true a wheel 1/4" wide. The usuall dressing for a glass cutting wheel is to use a soft but coarse AlOx stone to clean the glass swarf from between the diamond particles.

[Konrad]

For dressing a Diamond Wheel on a Surface grinder, I have build a dresser, which consist of housing, with a shaft thru on bearings, and have a break built into it, sort of a bronze rod, spring loaded, where you can turn a knurled wheel [knob] on the outside of the box housing, The shaft would stick out on both side, on one side you make a grinding wheel adaptor, that's going to be your dresser, on the other side a handle, where you crank it while dressing, the brake help you, so the grinding wheel is not going to speed up with the Diamond Wheel.You can use just about any grinding wheel you have on hand. We use something like a 1/2" wide, 4 - 5" in diam.

On the Cylindrical Grinder, we hold the grinding wheel in a Mandrel and put in between centers.

It is always important, before you run your wheel, dial it up first, it should have no more then .001 to .002 run out, the closer the better!

This type of dressing, doesn't dress much off the wheel, basically just cleaning it!
Konrad

[ESjaavik]

@Konrad: Thanks for the info. That takes care of the cleaning.

Can you please give some info on how to "dial up" the wheels?

One is made up of the diamond/binder ring on a wheel made of brass mounted on an arbor with a cone to match the grinder shaft and balancing weights. (Not CNC grinder.)

Another variety is on an aluminum wheel mounted on a common shop grinder. The PO used it for hand grinding. I will transfer it to a tool grinder mount of the same kind as above mentioned. If I can make it run without any runout I will only need to clean it as you wrote. Unless PO used it for too long with the runout of course.

One way I thought of is to mount it with the grinding surface onto the faceplate of the lathe and skim off the rear of the wheel. Will this work OK?

[Konrad]

"dial up a wheel", just tighten your wheel lightly, put your dial to it and turn by hand, you can tap the wheel with a soft plastic hammer to move it, until running concentric, then tighten the wheel and check again.

Skimming off the back, as you mentioned, sounds like a good idea! [for cup wheels]
Konrad

[ViperTX]

Originally Posted by keithorr I true diamond wheels for grinding glass by using SiC dressing stones. The kind you would use to hone a knife. To remove high spots, I cut into the flat of a SiC brick so there is full contact for about a sixth of the wheels circumference. Coming to a full stop with consistent contact pressure is also part of the dressing process. The SiC works to flatten the face and true an out of round wheel. It can take about 5 minutes of farting around to true a wheel 1/4" wide. The usuall dressing for a glass cutting wheel is to use a soft but coarse AlOx stone to clean the glass swarf from between the diamond particles.

I suspect that what you are really doing is removing the glass swarf buildup which builds up between the diamond particles......diamond is much harder then Silicon Carbide.

[keithorr]

Originally Posted by ViperTX I suspect that what you are really doing is removing the glass swarf buildup which builds up between the diamond particles......diamond is much harder then Silicon Carbide.

Diamond is harder, but the greenstone does reshape the wheel. The diamonds get chipped and flicked out of the matrix and the metal between is ground down. It will true an out of round wheel. It will remove high/hard spots. It will reshape the surface of the cutting edge. After the wheel has been trued and shaped with SiC, it cuts poorly. The matrix does not present sharp diamond corners. It still needs to be dressed with AlOx before grinding the next piece of glass. I've been doing this for the last 25 years. The AlOx dressing sticks are less abrasive and are used to clean the diamond tools between pieces.

[HuFlungDung]

Thanks for the info, Keith. Its great to have the input of someone who knows how to do it

[tjones]

Old post here but I just had to reply.

We dress diamond and CBN in 2 main ways. Using a common bond wheel (sand wheel) rotating at a slow RPM or on a brake truing device (brake keeps wheel running slow). Norton makes a brake truing device as well as rotary dressing systems using diamond rolls.

I run manual grinders along with Jungner CNC tool and cutter grinder. I have installed several of the rotary dressers but I still use the arbor in the workhead running about 100 rpm to dress with as well. Diamond rolls can be used to dress formed wheels with extream accuracy.