Bench Grinder

I've just bought a diamond wheel-dresser which is a steel rod with a block of steel at the end with a 1.5" x 1/2" face with coarse diamonds
stuck to it. Anyone know how the diamonds are attached? And how rugged are these things to having the diamonds knocked off? Can you just push it against a wheel at any angle? I mean with the leading or trailing edge of the dresser hitting the wheel first? Or must you be careful to get the centre of the dresser to hit the wheel first? Should the dresser be held against the tool rest, or can you just hold it freehand? Are light "cuts" advisable? I've been a naughty boy and used the wheel for aluminium. I have stood to one side, just in case, however.
Also. I've just bought a new slower speed grinder (1425 rpm - 4-pole on 50Hz) with a gray GP wheel and a white alumina wheel. Which would be the best for touching up carbide-tipped lathe tools? Way back, I just used the grey wheel that was in the grinder without a thought. jack
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They are usually set in a copper alloy of sorts.

Unless yours is one of the plated variety (it would likely be nickel colored if so), you don't have to worry about knocking the diamond off, it's not just glued on the surface. It is held captive by being poured in the matrix.

It's your dressing tool (they're called a cluster diamond), so use it as you wish, but if you want it to last, make sure only the diamond comes in contact with the wheel. If you introduce it at a wonky angle, you may hit the matrix instead of the diamonds, and that has the potential to screw up the mounting such that you could lose diamonds on the periphery of the tool.

While you may be able to use it freehand, a rest helps control the cutting action. It's also a little safer, If you slip freehand, you can end up tangled with the wheel. You can believe me when I tell you that hitting a running wheel with your hands can ruin a good day.
Are light "cuts" advisable? I've been a naughty

Don't horse it----but insure that it makes contact well enough to actually do something to the wheel. Introduce it to the wheel, then work it sideways, slowly feeding inwards until you have the surface of the wheel as you like it. Keep it moving side to side to avoid creating grooves in the wheel, which can actually ruin the dressing tool.

Neither one.
While I don't recommend them, aside from diamond or CBN, only a silicon carbide wheel will perform with any degree of satisfaction on carbide. Aluminum oxide (both of your wheels are aluminum oxide) is far too soft to be effective.
If you want really good results, buy a diamond wheel, and run it wet. Otherwise, a green silicon carbide wheel will work. The dust is hazardous------causes silicosis-----and the finish such a wheel leaves leaves a great deal to be desired. Silicon carbide (green wheel) isn't all that much harder than carbide, so it tends to club it off instead of cut it cleanly the way a diamond wheel does.

And it did a poor job of almost everything, didn't it?
Harold
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I tried a green wheel once and took Harolds advice and bought a diamond wheel. Like night and day. The carbide isn't chipped with the diamond unlike it was with green wheel.
Wes
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replace unlike with like
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Green for roughing and forming, diamond for finishing
Gunner
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
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On Tue, 25 Dec 2007 19:30:43 -0800, Gunner Asch

Does this mean that the diamond wheel wears out? Or is the diamond wheel just so much more expensive that you avoid risking damage as much as possible?
All I want to do is touch up the odd carbide tipped metal lathe tool, and various HSS woodworking tools. Perhaps some diamond strops, or files might be better? I suspect I will not be reshaping any carbide tools, just putting an edge on them occasionally. jack
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wrote:

Certainly, diamond wheels have a finite life----but keep steel off of them and run them wet, and you can expect one to last your lifetime. I ran my first diamond wheel for 16 years in a commercial environment. It wasn't shot, but had worn unevenly because the setup wasn't perfect. It would have lasted at least another 5 years otherwise.
The use of green wheels for shaping carbide isn't in your best interest. It is far more expensive to use green wheels than diamond, but you can buy a single green wheel for a lot less money than a diamond. Problem is, they wear out much faster, so in the long haul they cost more to use. The most undesirable feature is tools sharpened with silicon wheels tend to perform very poorly as compared to tools ground with diamond.
Be advised, your health is at serious risk if you use silicon wheels routinely. Avoid the dust from any such wheel, be it green or black.

Makes a good story, but in practice it never works out that way. What do you do if you chip a tool? (And you will!)
Buy/build a high speed wet diamond setup, select a relatively fine wheel (my choice is a 220), and let it serve you for the rest of your life.
I'm keen on grinding HSS without a rest, but carbide doesn't respond well to that. One of the reasons is that carbide is typically ground with much shallower relief, and it's easy to round the cutting edge, or to grind excessive relief. Tools so ground tend to be very poor performers, either cutting poorly, or enjoying a very short cutting life. All of that can be avoided by grinding with a rest, and a firm understanding of good and proper tool angles. You should have an adjustable table for grinding carbide. Offhand grinding isn't in your best interest.
Harold
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Seeing how well the 150g diamond cut vs the green wheel, I'm going to disagree this time.
Wes
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wrote:

That's true, even with a finer diamond. My 220 kicks ass compared to a silicon wheel.
I've been around this stuff for more than 50 years now----and have yet to see one good reason to use silicon over diamond------for anything.
The myth has been hard dying. There was a time when diamond wheels were cost prohibitive----so they were not commonly found in the shop. That's not the case any longer. A diamond wheel that used to cost $600 is now readily available for under $200------so the cost is down more than 300%, but the dollar has declined in buying power tremendously as well. It's clear, the cost of diamond wheels today is but a tiny fraction of the cost when they would recommend the use of green wheels. They make NO sense today, NONE!
Gunner lacks the proper exposure to understand what I know all too well.
Harold
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I'd have gone with the 220 as you recommended back in October but enco had a 150G 1/16" resin bonded 6A2C wheel for sale at slightly under 57 bucks. I figure I'll learn on this one and when it wears out hopefully Norton will be in my budget.
Wes
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On Wed, 26 Dec 2007 06:30:09 GMT, with neither quill nor qualm,

I think you mean 66.67%, don't you? 300% would make them give you $1,200 for every wheel you take from them. I'd like to attend that sale, so let me know when that happens, won't you, 'Arry? <g>
We got our first dusting of snow yesterday afternoon, and there's about half an inch on the tree branches now. It melted off the ground so far. How's your White Christmas coming? And how are your neighbors in flooded Chehalis doing?
-- Once we believe in ourselves, we can risk curiosity, wonder, spontaneous delight, or any experience that reveals the human spirit. --e e cummings
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quickly quoth: snip---

Sigh!
I seem to have been comparing against the wrong number. Perhaps that explains why I never received that $1,200 of which you spoke.

You're lucky! It started snowing here mid afternoon, and never really stopped. We have about 8" of snow on the ground as we speak, although it has quit snowing for the moment. They're threatening us with more tomorrow. I hate snow. Rotten damned stuff knocked out our power about 4:00 AM.. Luckily, we placed a call to get it restored, which happened about 8:30. Took a walk when it got light enough to see and found a branch had dropped across two phases of our 3 phase service, knocking out one leg. We, alone, were out of power, so it's a good thing we called. Otherwise, they'd have never known.
As luck would have it, records show that our area has had a white Christmas only five times in the past 100 years. Make it six in 101!
We drove to Chehalis Monday morning. Things are looking a lot better, but far, very far, from being back to normal. Some of the stores had more than 6' of water inside, while others received just several inches. The state liquor store is out of business for the time being-----and a few other businesses are still not open. Large stores are back in business, although some are restricting hours (Home Depot, for one) and don't have a full compliment of wares. The flood is recognized as the worst one to hit, according to records.
Thanks for asking.
Harold
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On Wed, 26 Dec 2007 17:22:07 GMT, with neither quill nor qualm,

Oh, darn. I could use a good diamond wheel and an extra grand or two. My shipment of heavy metal came in last week. I picked up my brand new Toyota Tundra (gold instead of white, long story) and am having fun with it already. I may go out in the snow later to see how it drives with Michelins in the white crap.

It has started and stopped 3 times since I wrote that. It's about 33F out there so most of it melts pretty quickly. I sent my family over the Siskiyou Summit this morning at 9. They usually keep I-5 pretty clear.

Pretty wild! We still have the noisy power we always do. Within the first year of moving up here I ended up putting a UPS on my computer to keep it from rebooting 3-5 times a day, and last year I added one to my entertainment setup. <sigh>

I think we've had 2 since I've been here (6 years in Feb.)

Ugh!

Best of luck to you all.
-- Once we believe in ourselves, we can risk curiosity, wonder, spontaneous delight, or any experience that reveals the human spirit. --e e cummings
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wrote:

Yeah, if you believe the rumors. Green wheels offer no advantages---diamond will rough faster and better.
Harold
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There is one.
When roughing and reshaping, the green wheel will cut the steel backing of a brazed carbide tool as well as the carbide itself. You don't want to do that with a diamond wheel.
John Martin
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wrote:

There is one.
When roughing and reshaping, the green wheel will cut the steel backing of a brazed carbide tool as well as the carbide itself. You don't want to do that with a diamond wheel.
John Martin
---------------------------------------------------------------------------------
To which I replied:
I'll be damned if I know why this thing hasn't got the proper tick marks to represent a reply, but even rebooting didn't change how my reply came up.
While it's true that a green wheel will grind steel with some degree of success, it isn't a good choice, no more than using diamond. Steel has an affinity for carbon, thus it dissolves the green wheels much the same way it dissolves diamond. When you grind steel with a green wheel, you experience premature dulling and shedding of the abrasive bits, shortening, substantially, the useful life of the wheel, plus rendering it somewhat less aggressive towards the carbide. Relieving the steel with an aluminum oxide wheel is always the best idea. The only advantage of using silicon carbide on tungsten carbide evaporated long ago, when diamond wheels became affordable.
Harold
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Harold, I set up my baldor carbide grinder with a diamond on one plate and a small relief (5 degree?). The other plate at maybe 10 degree and an old green stone.
I ruff on the green stone and finish on the diamond. As I often use insert tooling, I only sharpen a few carbide bits a year. Would you change anything?
Karl
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If you're happy with the results you're getting, no, I wouldn't recommend you change anything, although you might consider reducing your roughing angle, closer to the finish angle. Relieve the steel before using the green wheel, and stop a bit short of having the tool where you want it. Let the diamond bring it in-----which will happen quickly-----and will limit the amount of carbide you remove. The real benefit will be ending up with minimal relief, for strength.
When your old green wheel is gone, you might consider not replacing it. Use the diamond wheel alone. There's really no benefit in using the green wheel, but if you have it, you'll leave a few more miles on your diamond wheel by using it.
Consider that unless you're a youngster (I think those days are gone for both of us, eh?), you're highly unlikely to wear out your wheel if it's a resinoid bonded one. If, on the other hand, you use a plated wheel, I'd stick with the green wheel for roughing. Resinoid bonded wheels last for years unless you abuse them. Pound for pound, you can grind carbide much cheaper with diamond, and do a much better job. Most guys go with a green wheel because the initial investment is much smaller----but so is the performance. Silicon carbide, alone, is a false economy.
Harold
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On Wed, 26 Dec 2007 06:10:37 GMT, "Harold and Susan Vordos"

If you have a good selection of (expensive) diamond wheels. Green wheels are cheap.
Gunner
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
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wrote:

I'ts all in your perspective. You need but one diamond wheel to address almost all your sharpening needs for lathe tools----the only limitation being grinding chip breakers, and even then you're only limited, not prevented.
The cost of three green wheels will buy you a diamond wheel, which, in turn, will do the work of 20 green wheels. I don't see green wheels as being cheap, and their performance sucks big time. Then you have to consider the hazard of breathing the silicon.
I've been forced to use a silicon wheel when it really mattered----but the shop in question was run by a bunch of dolts that had no clue and wouldn't even entertain the idea of a diamond wheel. They wasted more money in carbide annually than the value of a decent diamond wheel. As I said, silicon carbide wheels are a false economy. The only thing to recommend them is that they will shape carbide, at least after a fashion. I hesitate to use the term "sharpen", for obvious reasons.
Harold
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