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MichaelP
03-10-2011, 01:39 AM
What are your preferences for a diamond dresser for surface grinder wheels? Simple block with a diamond point or something that can be extended vertically? Any particular design or model you prefer? What diamond size, length and shank diameter would you choose? (Note: radius grinding is not something I need in this case).

What about your favorite bench grinder wheel dresser? What do you like to use for an 8" one? I'm not too happy with the ones I use.

Thank you.

Doc Nickel
03-10-2011, 02:50 AM
Diamonds, of course, in both cases. I became a huge fan of using diamond points on my bench grinders once I finally set one up and properly used it.

The star wheels and Norbide sticks aren't bad, but really, all they do is scrape off the top layer of dull grit, and maybe do some rough leveling out if you have some shallow grooving.

But a diamond, with a proper stop/guide (http://www.docsmachine.com/projects/baldor/baldor-09.html), can true the wheel- as in remove the eccentricity/out-of-round of the stone.

This made a huge- pun intended- difference with my big 12" 2HP pedestal grinder with 2" wide rocks. Even at full speed, you can damn near balance a nickel on top of the motor case.

For the surface grinder, I've just been using the mounted diamond on a typical flat block, which generally works fine. But I'm rapidly coming 'round to the idea of one of those diamond holders with an adjustable height- I've had a few jobs where I had to crank the wheel down several inches to dress, then back up to the working surface.

Something that could be stuck down to the magnet, and then the arm with the diamond swung into and out of the way would be very handy at times.

For that matter, I also need a very low diamond for the same reason- grinding a .055" shim, crank the wheel up to dress it on a 2" tall diamond, then back down to the shim. A point on a 1/4" or even 1/2" tall plate would also be a time-saver.

Doc.

vpt
03-10-2011, 08:20 AM
I have the star wheel dresser type tool. I like it and it works good for my 1" wide 10" stones. I always get one deep groove from sharpening tungsten all the time in one spot (no matter how hard I try to use the whole stone). The star tool takes any aluminum off the stone and flattens it out quite nice for me. Takes no time at all to take 1/8-1/4" off the stone if needed.

Mcgyver
03-10-2011, 08:34 AM
Diamond for the surface and tool grinders. I haven't bothered with height adjustment, just s block with a round piece welded at an angle and set screw to hold the diamond.....but I can see the advantages of it, maybe it will get added to the list. If not obvious always dress behind the centre line, ie so the dresser can't get pulled in and jam.

A star wheel works well for the bench grinder. I made a little adjustable diamond carrier that'll go across my diy bench grinder tables. It works the best of all methods, but the star is so much quicker and does a reasonable job it lazily gets used more often.

moe1942
03-10-2011, 09:02 AM
Dressing the wheel just shortens its life. Move the tool evenly across the wheel and it won't need dressing.

aboard_epsilon
03-10-2011, 09:13 AM
Dressing the wheel just shortens its life. Move the tool evenly across the wheel and it won't need dressing.

bench grinders yes maybe ..
but surface grinders have to be dressed...not nessisarily for wear reasons ..the stone gets blocked or they pick up oils on the stone..leading to bad finishes.

i just have a block of steel that has a dimond tool in it ..that i put to the left hand side of the wheel

all the best.mark

Dr Stan
03-10-2011, 10:50 AM
Dressing the wheel just shortens its life. Move the tool evenly across the wheel and it won't need dressing.

Not true, as the wheel is used the abrasive particles become rounded and dull. In addition even when grinding steel the wheels become loaded. Both conditions require dressing for if you do not do so you run the very real risk of applying too much pressure and 1) burning/over heating the object being ground and 2) slipping off the face of the wheel and running your hand into the spinning wheel. :eek:

As to the dressers, I use diamonds for both. One made by Geiger is my favorite for bench/pedestal grinders as a previous poster said it not only cleans the face of the wheel but also trues it virtually eliminating the vibration which in turn improves ones grinding. You can see an example at: http://www.travers.com/skulist.asp?RequestData=CA_Search&navPath=All+Products%2F%2F%2F%2FUserSearch1%3Ddiam ond+dresser&q=block+id+84137+and+class+level3+id+29964&minPrice=$39.62

Alistair Hosie
03-10-2011, 01:12 PM
I use mostly 8 inch grinders with blue, white, or pink ,stones except on two grinders. One is ten inch and another one is eight inch in my machine shop I left both of them with the wheels they came with.I find the ten inch are expensive to replace if you want good wheels that is probably why I left that one as bought . I only use a single diamond which I have just used and a t type multidiamond which for my money is much better I have never used a star type don't like the look of them too agressive for trimming/tidying purposes. Alistair

RWO
03-10-2011, 02:02 PM
The so called diamond dressers are really truers. They cut the abrasive grain and return the wheel to the proper shape. However, the cut face is not a good surface to begin grinding with as all the abrasive teeth have been shaved off. A star-wheel or norbide stick will open up the abrasive grain and restore the teeth by knocking out some of the binder without changing the basic shape of the wheel.

So, true up the wheel with a diamond and lightly apply the dresser to restore that abrasive face to full sharpness and you are good to go.

RWP

bborr01
03-10-2011, 02:38 PM
The so called diamond dressers are really truers. They cut the abrasive grain and return the wheel to the proper shape. However, the cut face is not a good surface to begin grinding with as all the abrasive teeth have been shaved off. A star-wheel or norbide stick will open up the abrasive grain and restore the teeth by knocking out some of the binder without changing the basic shape of the wheel.

So, true up the wheel with a diamond and lightly apply the dresser to restore that abrasive face to full sharpness and you are good to go.

RWP

If you need to use a norbide stick or a star dresser after you dress your wheel with a diamond, you probably need a new diamond.

A sharp diamond will leave a grinding wheel sharp and ready to cut. If the diamond gets dull and rounded off, it had a tendency to glaze the wheel and not cut well.

Look at your diamond under a microscope and compare it to a new one.

I spent many years grinding all types of material with most types of grinders and used a diamond on all but the Blanchard and snag grinders.

Brian

MichaelP
03-17-2011, 11:50 PM
Brian,

I have a bunch of different diamonds that were sold to me as new. However, I have certain doubts about it. The diamonds are shaped differently: some of them have faucets, some are just conical. The tips on all of them look reasonably pointed (no rounded tips), but neither the points nor the faucet edges look razor sharp. Some of the holders look quite rough (which I wouldn't expect from Norton): the conical part where the diamond are mounted have circumferencial marks that look like typical lathe tool marks.

What do you think? Can new Norton diamonds be like this? What would be the signs of previous use? Do you happen to have macro photos of new diamonds?

Thank you.

J Tiers
03-18-2011, 12:12 AM
On a related topic, how worn can a star wheel dresser be and still be useful?

PeteF
03-18-2011, 02:13 AM
Michael the diamond I have was simply rounded when new, a bit like a crayon I guess, but as you use it the wheel wears facets in it. On that note, if you build your own fixture, have it at an angle and not vertical, that way you can rotate the diamond each time and get much more life from it. It probably also results in a better finish on the wheel too, but I don't know that for a fact.

I've only been using a surface grinder for the past 2 months or so, and am definitely no expert in them, but it's my new toy so the novelty value is high and I've been using it quite a lot until this week when I stripped and rebuilt it. Mine is a small 6 x 12 grinder. I don't have a magnetic chuck as yet so have often been using just a chuck. I simply hold the diamond dressing tool at an angle in the chuck and it works perfectly. I can only imagine anyone who suggests you don't need to dress a surface grinder wheel has never actually used one. Each time you mount the wheel you need to dress it true, if you don't it leaves little patterns in the work. The other thing is the wheel becomes dull and that it really obvious, even to a newbie like me. The work starts to get much hotter, the cuts sound different, with the same depth cut the motor is working harder, but most of all the finish is just crap. Sometimes I've found I can extend the time before dressing as the following part of the wheel will clean up the finish left by the leading edge, but not too long after that stage there's no alternative but to stop and dress it. That's been my experience so far anyway.

Pete

bborr01
03-18-2011, 11:52 AM
Brian,

I have a bunch of different diamonds that were sold to me as new. However, I have certain doubts about it. The diamonds are shaped differently: some of them have faucets, some are just conical. The tips on all of them look reasonably pointed (no rounded tips), but neither the points nor the faucet edges look razor sharp. Some of the holders look quite rough (which I wouldn't expect from Norton): the conical part where the diamond are mounted have circumferencial marks that look like typical lathe tool marks.

What do you think? Can new Norton diamonds be like this? What would be the signs of previous use? Do you happen to have macro photos of new diamonds?

Thank you.

Michael,

I don't have any pics of diamonds, either sharp or dull.

Couple of other things you might try.

Many people tend to over dress the wheel. This leads to glazing of the wheel.

Think of a grinding wheel this way. A grinding wheel works much the same way as a milling cutter, but on a much smaller scale.

The sharpness or roughness of the stones in a grinding wheel act much like the teeth of a cutter. If you wore all the flutes off from a cutter, it would not cut. Grinding wheels are the same way.

When dressing a wheel (as in a surface grinder wheel), many people try to get the wheel as smooth as possible. Not good. Round and true are good. Too smooth is not good.

Make ONE pass with the diamond at a fairly rapid speed. (one to two seconds to dress a 1" wide) DO NOT DRESS THE WHEEL ON THE RETURN TRIP OF THE TABLE. THIS LEADS TO GLAZING. (unless you are still dressing and feeding the wheel into the diamond.

One other thing. Depending on the width of the wheel, quite often I and many others would relieve the wheel on the backside on the cutting surface by maybe .010" or so.

On a 1" wheel I might only use 3/8 of the 1" width. You get a better finish that way. It allows the wheel to break down somewhat instead of glazing the back portion of the wheel.

I hope this explanation helps.

Brian

bborr01
03-18-2011, 12:03 PM
On a related topic, how worn can a star wheel dresser be and still be useful?

I would way that as long as there is still star left, it should still work. Probably not as good as when it was new, but still work.

I seldom used a star dresser. We kept one chained to a big snag grinder that got used a lot for roughing. When the wheel became un-usable, out came the star dresser.

It is easy to get spoiled by dressing with diamonds. (now I am sounding like my wife:D ) Dressing grinding wheels with diamonds that is.

Brian

MichaelP
03-18-2011, 05:19 PM
I and many others would relieve the wheel on the backside on the cutting surface by maybe .010" or so.

On a 1" wheel I might only use 3/8 of the 1" width.
Brian, do you mean you you remove the back 5/8" portion of the 1" wheel periphery to the depth on .010"?

PixMan
03-18-2011, 05:30 PM
One other thing. Depending on the width of the wheel, quite often I and many others would relieve the wheel on the backside on the cutting surface by maybe .010" or so.

On a 1" wheel I might only use 3/8 of the 1" width. You get a better finish that way. It allows the wheel to break down somewhat instead of glazing the back portion of the wheel.

I hope this explanation helps.

Brian

I've been at this machining thing for 30 years and have never done that. After all, what is the point of having a 1" wide wheel if you're using it like a 3/8" wheel? As long as you have a good straight dressing of the wheel, the width of it will NOT glaze the work piece. Instead, the wide wheel acts as a sparkout as you make a pass, avoiding the need to take a separate "zero depth-of-cut" sparkout pass.

The leading edge part of the wheel still breaks down, assuming you have the right kind of wheel for the work at hand. The benefit of a wider wheel is that the trailing width of the wheel is still sharp and cleans off any remaining material as it passes.

In fact, I used to run a Snow reciprocating surface grinder with a 6" wide wheel. I think I'd be canned if I did a relief dressing for 5-5/8" the wheel width.

PeteF
03-19-2011, 12:08 AM
I've been at this machining thing for 30 years and have never done that. After all, what is the point of having a 1" wide wheel if you're using it like a 3/8" wheel? As long as you have a good straight dressing of the wheel, the width of it will NOT glaze the work piece. Instead, the wide wheel acts as a sparkout as you make a pass, avoiding the need to take a separate "zero depth-of-cut" sparkout pass.

The leading edge part of the wheel still breaks down, assuming you have the right kind of wheel for the work at hand. The benefit of a wider wheel is that the trailing width of the wheel is still sharp and cleans off any remaining material as it passes.

In fact, I used to run a Snow reciprocating surface grinder with a 6" wide wheel. I think I'd be canned if I did a relief dressing for 5-5/8" the wheel width.

FWIW that's precisely what I find, and tried to describe above. Initially the leading edge of the wheel breaks down and glazes up, but the resultant poor finish is cleaned up by the following trailing edge. That glazed area slowly works its way across the wheel and eventually the whole wheel glazes to the extent that it needs to be redressed. I definitely can't understand why one would want to relieve the trailing edge of the wheel unless it was for some form of profile grinding.

Pete

bborr01
03-23-2011, 11:52 AM
Brian, do you mean you you remove the back 5/8" portion of the 1" wheel periphery to the depth on .010"?

Hi Michael,

Sorry about the delay responding. This thread got away from me.

Yes, after dressing the wheel I would sometimes dress the back part of the cutting surface by .010 or so. That helps keep glazing of the wheel down.

Of course, using a 1/2" wide wheel is a better option. But sometimes that may not be possible.

Brian

MichaelP
03-23-2011, 03:17 PM
Thank you, Brian.

moe1942
03-23-2011, 04:33 PM
bench grinders yes maybe ..
but surface grinders have to be dressed...not nessisarily for wear reasons ..the stone gets blocked or they pick up oils on the stone..leading to bad finishes.

i just have a block of steel that has a dimond tool in it ..that i put to the left hand side of the wheel

all the best.mark


I stand corrected. I missed surface grinder..I stand by what I said for all other applications provided it is a quality wheel of the correct frangible or friable grade. Then it simply becomes a matter of knowing how to grind correctly.

I'm not trying to convince anyone. Just commenting on how I've done it for over fifty years..I'm also frugal.

bborr01
03-23-2011, 06:55 PM
I've been at this machining thing for 30 years and have never done that. After all, what is the point of having a 1" wide wheel if you're using it like a 3/8" wheel? As long as you have a good straight dressing of the wheel, the width of it will NOT glaze the work piece. Instead, the wide wheel acts as a sparkout as you make a pass, avoiding the need to take a separate "zero depth-of-cut" sparkout pass.

The leading edge part of the wheel still breaks down, assuming you have the right kind of wheel for the work at hand. The benefit of a wider wheel is that the trailing width of the wheel is still sharp and cleans off any remaining material as it passes.

In fact, I used to run a Snow reciprocating surface grinder with a 6" wide wheel. I think I'd be canned if I did a relief dressing for 5-5/8" the wheel width.

Pixman,

A couple of things. Relieving the wheel is not to keep the workpiece from glazing like you said. It is to keep the WHEEL from glazing.

I also would not reccomend relieving 5 5/8" of a 6" wheel.

This technique is not something that I came up with.

Our tool room grinding department had several dozen grinder hands that spent minimum 40 hours a week doing nothing but grinding, some of them for several decades. I consider their collective knowledge to have been pretty immense.

If you think trying something new like dressing another .010" off a grinding wheel would get you fired, you might want to consider what type of people you are working for.

I consider myself kind of a rookie compared to them guys. I only ground full time for about the last ten years of my career, after a couple of major leg injuries limited my ability to build and service automation.

I did however spend a lot of time grinding jobs that most job shops would never even attempt. Cold former tooling made of M4 and carbide that required super microfinishes and inspection under a microscope befory trying to run it. Carbide stamping die tooling. I also found that taking advice from those more experienced than me to be a big plus.

As the old saying goes, if you keep doing the same thing, you can expect the same results.

Brian

tdmidget
03-23-2011, 10:01 PM
Brian, if you have to do that, you are using the wrong wheel. I don't care how many years those guys claim to have done it, it's wrong. You won't get that kind of advice from Norton, where they have a research facility full of grinding machines even though it would sell a lot of wheels. Some of the worst old wives tales come from those who have done it wrong so long they think it's right.

bborr01
03-23-2011, 10:24 PM
Brian, if you have to do that, you are using the wrong wheel. I don't care how many years those guys claim to have done it, it's wrong. You won't get that kind of advice from Norton, where they have a research facility full of grinding machines even though it would sell a lot of wheels. Some of the worst old wives tales come from those who have done it wrong so long they think it's right.

TD,

Read post #19.

As I said there, "Of course, using a 1/2" wide wheel is a better option. But sometimes that may not be possible."

What I am trying to say is that a wider wheel is not better, otherwise we would always use the widest wheel available.

Brian

tdmidget
03-23-2011, 10:41 PM
Wrong doesn't mean wrong width. Width is immaterial if everything else is right because you are only grinding with the edge, what ever your crossfeed is. Obviously if that part does it's job then the part of the wheel that is cutting slowly moves across the wheel. If what you say is true then there would be no need for wider wheels. If your wheel is "glazing" ( a poor term for something made basically of glass) then the wheel hardness, structure or composition is wrong.

bborr01
03-23-2011, 10:52 PM
Wrong doesn't mean wrong width. Width is immaterial if everything else is right because you are only grinding with the edge, what ever your crossfeed is. Obviously if that part does it's job then the part of the wheel that is cutting slowly moves across the wheel. If what you say is true then there would be no need for wider wheels. If your wheel is "glazing" ( a poor term for something made basically of glass) then the wheel hardness, structure or composition is wrong.

Never mind. You're the expert.

Brian

noah katz
03-23-2011, 11:01 PM
Gotta say I don't get relieving the wheel either.

Of course the wheel won't get glazed if it's not contacting the work - .010" is more DOC than you'd ever do on a surface grinder, right?