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
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?
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.
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
Thanks, Harold, this thing is silver all over (looks plated). Does this mean it is fragile? If so, how should I care for it over and above what you recommend in general?
This has many 50 grit diamonds, maybe thousands. I doubt you could hit matrix without being wasted by diamonds beforehand.
This I know, but don't ask me how :)
By horse it, I guess you mean push it in so hard it slows the wheel?
Why is one white and one grey? The Al2O3 white one is meant for HSS and apparently does a better job on that, so what is the grey one meant to do? The white wheel has WA 12 L stencilled on it, and the grey has A 60 M, I think (not too sure about the A as only half of it got stencilled) Then there is the maker's brand, and 40 m/s.
Can you do this on a 1425rpm dry grinder? What would an 8" diamond wheel likely cost? Would you just let water drip slowly from a bottle on a shelf via a plastic tube?
Seemed OK to me, but then, I'm just an inexperienced amateur. Maybe it had a SiC wheel in it, coz it seemed to put a nice edge on out carbide tools. This was just a small lathe in a university laboratory workshop.No critical work was ever done on it.
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
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.
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.
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.
That be the case, yeah, the diamond isn't all the securely set. I highly recommend you do not use it to knock off the aluminum you mentioned. Use a dressing stick or a star dresser to remove the aluminum, then use the diamond to smooth the wheel.
You may not like the surface the diamond cluster leaves. Diamond, being very sharp and hard, will prepare the surface so smoothly that it won't grind as well as a wheel that is dressed with a star dresser. The advantage of the cluster diamond is that it's a lot easier to get the wheel true. You may find that you can use a (sintered) dressing stick to slightly rough the wheel once it's true, which will actually improve its cutting characteristics. I use dressing sticks almost exclusively for my pedestal grinder, although on rare occasion I'll use a mounted diamond to move a lot of wheel when it's required. For grinding HSS off hand, a diamond dressed wheel is not good at all.
I happen to know a bit about that as well! I'm getting the distinct idea that it's for the same reason. :-(
I'm not convinced you could put enough pressure on the wheel to do that. In your case, if you push too hard, you could dislodge diamonds. The aluminum that's present will do its best to do so anyway. I was struggling with the notion that you had a matrix set cluster, not a plated one. Be real careful with the plated one-----the only thing that holds the diamond on is the plating that is applied to the entire thing. Diamonds, being conductive, allow for full encapsulation with nickel, so once you uncover half the diamond, it's free to fall out, and often does. I suggest a light touch, allowing the diamond to do it's work without grooving the wheel. Keep the cluster in constant sideward motion, so it can't establish grooves in the wheel. They'll undercut the sides of the diamond, then they'll release.
How the aluminum oxide is made makes a difference in how it performs. That's why Norton offers various types of aluminum oxide wheels. Some are far better suited to grinding particular types of alloys---such as the 38A, which cuts fast and cool when grinding HSS. They all work, just some work better than others. The rank novice may not notice the differences at first.
Regards the markings, they defy common markings, so it's hard to say what they mean. I'd venture a guess that the L is the hardness, as is the M. The 12 is a mystery, unless it stands for 120, which would be a fine wheel. W I have no idea, but the A likely designates aluminum (oxide). The other marking makes more sense, with the A obviously aluminum (oxide), and the 60 the hardness. There's a lot more to wheel markings than yours display. My guess is they're not American made.
For carbide lathe tools, the type 1 wheel isn't a good choice. Carbide is best ground without hollow grinding, so a type 6 wheel is the wheel of choice. One that would serve your purpose very well would be only 6" diameter, and would have a 3/4" face (on the side of the wheel, which is the working surface). It yields flat grinds, so you don't undercut the tool, weakening the edge. That's important if you put tools to work. No big deal for scratch cuts, however, but then you are likely not taking advantage of the use of carbide if that's how you're using it. HSS would likely serve better unless you're machining hard materials.
If it put an edge on the tool and actually moved the carbide, it most surely was silicon carbide. Aluminum oxide is substantially softer than silicon carbide. So much so that when you apply tungsten carbide to an aluminum oxide wheel, it tends to glaze each of them without doing much more. You'd have a dreadful time trying to put an edge on tungsten carbide tools with aluminum oxide, and they'd likely cut very poorly because the cutting edge wouldn't be keenly sharp, which is key to performance with light cuts using carbide tools. Roughing cuts are far more forgiving, assuming you go to negative rake. That's a whole different world, not to be confused with machining with positive rake.
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.
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.
Sorry----I failed to address your question about the gray wheel.
I think you'll find it is bonded harder than the white one, so it is intended for grinding soft materials, such as mild steel, or even high carbon steels in the annealed condition. The rule of thumb is hard wheels for soft materials, and soft wheels for hard materials. It's all about how long it takes for the wheel to shed dull bits to re-sharpen itself.
Hardness, in grinding wheels, is not related to the media, it's related to how the wheel is bonded. A J wheel is softer than an M wheel.
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.
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?
On Wed, 26 Dec 2007 06:30:09 GMT, with neither quill nor qualm, "Harold and Susan Vordos" quickly quoth:
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?
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
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.
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.
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