Dressing wheel of surface grinder

How deep a cut should I be using when I dress the wheel of a surface grinder with a diamond? How fast should I feed it?
stan
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snipped-for-privacy@robustmachine.com wrote:

not very deep or it tends to send sharp "chips" off the wheel in all directions at very fast speeds. hand feed it.
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Hey Stan,
You didn't say much about the machine, but on my 6 X 18 I touch the diamond to the stone, out-feed clear of the wheel and drop the head 5 thou, then a fairly brisk non-stop in-feed all the way across. Repeat as necessary until the wheel is "clean" all the way across. Unless you've been doing something silly, two passes should do it.
Take care.
Brian Lawson, Bothwell, Ontario. XXXXXXXXXXXXXXXXXXXXXXXX
On 8 Dec 2006 18:49:41 -0800, snipped-for-privacy@robustmachine.com wrote:

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Excellent advice from Brian----with one more tip:
Depending on how you grind, you may want to take a final pass over the wheel, shallow feed on the diamond (half thou or so) and crank slowly, then reverse.That leaves a finer finish on the wheel, and dislodges any fine particles that tend to hitchhike after dressing.
There's two ways to surface grind. The one is to use a rapid cross feed ( half the wheel width or so) and shallow depth of cut (a thou or so). The other is to use a deep depth of cut (no more than about .008" when roughing the work piece) and a relatively fine cross feed, no more than .050", and usually around .030"). This is the method of choice for me. It yields a far better finish, and isn't any harder on the wheel. It also provides for far better precision because all the cutting takes place on the corner of the wheel, leaving the balance of the wheel for spark out. Needless to say, it's a good idea to take all your cuts from the same side, although if you're roughing, there's no harm in grinding with both edges of the wheel before you dress. The wheel tends to degenerate with use, and starts performing poorly, so you know when it's time to use the other corner, or to dress the wheel. The wheel doesn't change size when you grind this way, as it does by grinding by the other method. The only negative from this procedure is that you must dress the wheel deep enough to remove the shoulder that is created by the depth of grind, but that is generally not much different from a dress that removes the loaded portion of the wheel that comes from grinding by the other method.
If you use the method I recommend, understand that it cries for coolant. I, for one, refuse to grind dry, knowing full well the amount of heat generated in the process.
Harold
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Gee, Harold...I hope you never see my on my surface grinder. You'd have an attack of some sort. 10 to 20 down, 30 - 50 across, no coolant. I guess that's why I buy wheels by the case. I am a bit more gentile with important stuff. I just want it done now!
I still can't find the right wheel for my Arter to do D-2. We can only take two tenths at a time. It's so slow, I'm thinking of farming it out again.
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snip--

an
important
But your Arter isn't a pigmy sized machine. I certainly wouldn't have given that advice for the guy with a 12 x 36 grinder. The typical home shop machine uses a 7" (or 8") x 1/2 x 1-1/4" wheel. There's not much wheel there to take the kind of abuse you're talking about.
Why aren't you running coolant? BIG mistake.

take
Blink!
Two tenths? Sort of contradicts what you just said.
How's the finish? What wheel you running? (Tell me the whole description, not just "Camel"). Sounds like you have lousy bearings.
Harold
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Sorry, I wasn't clear. My Excello grinder in the machine shop and the Arter are two different grinders. I also have a third surface grinder that is only set-up to sharpen moulder and shaper knives. The Arter uses a 14" wheel and is only used to sharpen my D-2 wire cutter blades. I have two sizes. 6" OD and 8" OD by 3/4" thick, 4" ID. with a 1 degree dish. The Arter is 7.5 HP. I had one wheel that came with the machine that cut these blades like butter. No markings! And, no supplier has been able to figure out what it was even after sending it out to their labs. I've tried eight different types of wheels that don't work well, at the recommendations of suppliers. I've come to the conclusion that grinding is a "Black Art" that requires the burying of chicken guts on a full moon and burning candles while wearing robes and chanting.
The Excello we use like an abrasive milling machine, you'd be ashamed! ...but it'll still hold a tenth or so.
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On Sun, 10 Dec 2006 08:24:33 GMT, "Tom Gardner"

===================Contact Artur and see what the machine shipped with?
http://www.artergrinders.com /
Unka' George (George McDuffee) .............................. Only in Britain could it be thought a defect to be "too clever by half." The probability is that too many people are too stupid by three-quarters.
John Major (b. 1943), British Conservative politician, prime minister. Quoted in: Observer (London, 7 July 1991).
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Mine was made in '42. The guy I bought it from might have changed the wheel.
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I doubt it. Don't you?
Harold
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Tom Gardner wrote:

Maybe not, you said it was a good wheel. :)
John
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D2 - what nasty stuff :-) -
High chrome and carbon and ......
These are shots in the dark, but are listed as shown.
Took reference in three books but it would appear you need [ based upon Precision Grinding Author Dr. V.E. Repp ISBN 0910399158 ] { usd $12.00 AMAZON} { National Tooling & Machining Association www.ntma.org } > 300 pages.
32A46 - I8VBE or 32A60 - G12VBEP [ Steel, Hard (Rc 55 and harder)
53A36-K8VBE (for soft steel up to Rc 55)
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
Tom Gardner wrote:

-
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I wouldn't kick a dead dog in the ass with a Camel wheel! I think I want a twenty-some grit with soft, open binder. I just can't get them. Suppliers keep recommending "Super Abrasives" and ceramic crap of some sort. Most of the try-outs have been in the forty-some grit with all different binders and grain. They just don't cut fast and I can only take two tenths at a pass or it boggs the motor. I just don't know enough about it all but my suppliers don't know shit either. I am using flood coolant on the Arter. This D-2, full hard, is just some tough stuff!!! My latest request to my supplier is for a single crystal with a hole in it...THAT might be coarse enough! ..A one-grit?
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Tom Gardner wrote:

Tom In a shop I worked in a while ago we did a lot of P20 and H13. We were getting our grinding wheels custom made, I can't remember the specifics of the wheel at the moment, but they were a mix of types and looked slightly grey in color. they were relatively soft, either I or J. I also used them in a second shop on plasma sprayed metals. Getting them custom made wasn't too much more than a regular wheel and we only got them in batches of a dozen.
James Crombie Design Engineer Silent Exhaust Systems http://www.silxsys.com
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Yep, that's where I'm at now...waiting for a quote on a custom. I hope I don't need to buy a dozen, the off-shelf wheels cost me $112 ea.
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Tom Gardner wrote:

I have had good luck with Norton custom made wheels. We do a lot of grinding on hard materials. A standard wheel costs me about 375 per wheel. A custom wheel runs 450 in quantities of 8 and they pay the shipping. We get about 1/3 more pieces with the custom wheel not counting the time it takes to change a 24x 12 x 3 wheel.
John
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HOLY CRAP! Thnat's a big wheel! Bet they ring like bells. Three men and a boy to change them? How much HP to run them? 50?
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Tom Gardner wrote:

We use them in a special machine we designed. The motor is 30 HP. To change the wheel you drop out the whole spindle and turn off the face flange. The spindle shaft is stationary with id of the spindle bearing on that shaft. A hollow shaft fitting the od of the spindle bearings fits the id of the wheel. The flange nut that holds the wheel is threaded onto the od of the hollow shaft. We use a fork lift to change the wheels. These are a fiberglass re-enforced wheel so they can take a lot of abuse. The grinding part of the machine is from a big slag grinder.
John
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For D-2, I've always used a 46-H.
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The typical home

No, it's really not a problem. I've taken as much as .050 in a pass. You just have to be careful with your cross feed. Grinders really need to be fed hard in order to cut well. The wheel NEEDS to break down so that you're always cutting with sharp grit. Grinding too slowly will actually generate more heat because the grit gets dull instead of falling off the wheel. You can tell by the sound of your grider if you're feeding too aggresively. Obviously there are limits. If the wheel disentigrates, and lodges into your neck, take smaller passes. :)

That depends on the size of your part. The thinner the part, the more you rough, and the more accuracy you need, the larger the demand for coolant. If your part is a couple of inches thick, and you're only taking off .01 or so, coolant isn't that big of a deal. If you really got to hold accuracy though, it's a good idea to let your part cool before taking the final pass.
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