grinding wheel clogged with aluminum

Excellent choice when it has a sharp corner. They're made of boron carbide, and far harder than silicon carbide. Problem is, just like a diamond, as they wear, they quit cutting the wheel and start glazing it. As long as you can keep a sharp cutting edge---they're very good.

Harold

I have serious doubts that it works as a star dresser. Indication are it is nothing more than a revolving vitrified dressing stick, likely silicon carbide. Star dressers work by hammering----they otherwise would be quickly wasted. I have no quarrel with your statement about the results of the device in question, but it's a high price to pay when a dressing stick does the same thing.

Please correct me if I don't understand the nature of the dressing device you suggested.

Harold

The wheel on the dresser normally runs at a slight angle. This provides the sliding motion of the dressing stick. But the rotary motion of the wheel pressing against grinding wheel causes a crushing action similar to but much more controlled when compared to a star dresser. For times when the grinding wheel is just dull and doesn't need any real dressing you can turn it to run straight on with the grinding wheel. This caused the crushing action which sharpens the grinding wheel without taking off any more than is needed. I can say from experience a wheel dressed this way will cut 5x faster (or more) than one dressed with a stick but still be as smooth and easy to control as a stick dressed wheel. My experience is that the surface left cuts better than any other method of dressing, diamond included.

Now for my big rough welding grinder I routinely use a star dresser. In fact I've got the largest size they sell which is so much better made and so massive that it does a pretty good job of smoothly dressing a wheel. I routinely sharpen my largest drill bits on that grinder after freshly dressing it flat with my star dresser (when sharpening a 2 1/4" drill bit it helps to have a grinding wheel wider than 1").

To give you a idea of how much I like the results of this type of dresser I'll say that I was very seriously considering making one for a while. At that time nobody I could find was selling them. MSC didn't have them for a number of years. Now as you know I've got a working shop and the time needed to make one would cost several times what they sell for. But I wish for one so often (like today when I was sharpening a HSS tool) that I had it on my list of things to build till I found them in the catalog. I currently use a dressing stick on my tool sharpening grinder and I'm definitely not satisfied with the performance of the wheel when I use it.

So far it sounds very good. The sliding motion you speak of helps eliminate any grooves or high spots in the wheel, but can also be the source of grain dulling. That approaches the performance level of a stick.

You likely know that crush rolling is one of the accepted methods of dressing profiles on grinding wheels, but it's usually accomplished at slow speed, powering the crush form, so the grinding wheel doesn't abrade the roll form, and the roll form doesn't dull the grain of the wheel. This tool is a serious compromise on that method, and likely still dulls the grain ever so slightly. Like a stick!

How much difficulty can you recall in getting a wheel rounded up when it's bouncing? Seems to me that applied pressure, if the tool works as you suggest, would make that task difficult. That's one of the complaints I've always had with a star type dresser, In order for it to function, it has to be loaded. If it's loaded on a bouncing wheel, it's a slow process getting the high out of the wheel because it's lowering the low side at almost the same rate as it's removing the high side. That's not true with a diamond or a stick.

I'll take you at your word, Wayne. I've never even seen one of the devices, and would hesitate to rush to judgment.

No need to rush to judgment here. This one is a no-brainer. A diamond dressed wheel is about the most useless wheel there is if you're offhand grinding. I've used more than enough diamond dressed wheels for just about any occasion you might imagine, from internal grinding to centerless grinding. There's nothing that equals such a wheel, but ONLY if it's run under power conditions, and generous flood coolant. For offhand grinding, they cut hot and poorly. A diamond dressed surface is just too smooth to be effective for hand work.

Didn't realize the size of work you did, but I fully agree here. The only reservation I'd have is that the wheel, unless well undersized, is very poorly matched to the work at hand. Doesn't mean it wouldn't work, just means it's too hard for good grinding of HSS

I can't help but think that part of your less than equal satisfaction is how you're using the stick, Wayne. I've been using one for well over 40 years, and I can get any wheel to cut well (I admit I don't have one of those trick dressing tools so I can compare), but I've used a star dresser and can come very close to the same performance they yield. Difference is that the stick always dulls the grain ever so slightly---but if you present sharp edges, that's almost not detectable.

One thing you have to learn to avoid is letting a flat side of a stick to rub on a wheel in the hopes of achieving a flat surface. If you're doing that, I have no doubt, you're not going to like the wheel when you're finished. That's not an acceptable technique----it dulls the wheel too much.

Thanks for the great report. Always a pleasure to read your posts.

Harold

Thanks Harold - cut and pasted your tutorial to NOTEPAD, goes in my file of things to get at the tool suppliers...

Andrew VK3BFA.

OK but... wont the dressing stick quickly wear out the sharp corner? You say that a stick will last a hobbyist a lifetime. How do we get a sharp corner to last?

I do not have one of those $2.90 sticks, was too dumb to pay $10 for a diamond but I am going to get one as soon as figure how to use it properly.

Thanks Mauro

I _hope_ you meant 6,000 fpm Harold

regards Mark Rand RTFM

The stick does slowly degrade, but keep in mind it's a vitrified product, so it not only wears, it also allows dull particles to dislodge. That exposes new, sharp grain, just like a grinding wheel. Understand that you won't have a *sharp* corner in the sense of a new stick, but you have projections that are not large in area, and act effectively on the wheel, very unlike a broad, flat surface. They work, and very well, but you have to develop the technique. That includes choosing the right places on the stick to apply to the wheel. It makes a lot of sense when you use it---but it may not sound logical unless you've "been there, done that".

Same way you keep a diamond sharp. Diamonds that aren't mounted in an offset holder, and are used only in one position, or are used free hand, eventually are dulled to the point they are useless. By mounting in an offset holder, as the diamond establishes a flat, you rotate it slightly, presenting the edge of the flat. Think like that when you use the stick. You're constantly creating new edges, the just aren't 90°, but they don't have to be.

To be best served, you should have a diamond and a dressing stick, and know when to use each one. That comes into focus quite readily when you start using them. Dressing stick is almost impossible to not have------particularly for those of us that have a background in grinding.

Harold

Large OOOPS!

Indeed, I did!

Thanks, Mark.

Harold

I have heard the same tale. Short of the aluminum bonding to the wheel and then expanding from the temperature increase as someone tries to force the wheel wheel to work and fracturing, I don't see how this would happen.

As far as first best method overspeeding seems like the ticket other than jamming something into the wheel, dropping a wheel and later installing, ...

Wes S

Not from the position of authority.

The theory, as I understand it, is that the spaces in the wheel that determine its ability to deal with swarf, get compacted, fracturing the wheel. I can see how it could be, but I've never read anything to substantiate the claim.

Aluminum should be ground with a silicon carbide wheel, not an aluminum oxide wheel. Proper structure helps in keeping the wheel from loading, but it's always a PITA to grind aluminum. I had to run it through a centerless on rare occasion. Never did achieve a level of success the way you could with ferrous alloys.

Harold

The angle is slight so the sliding is minimized.

I'm sure it does compared to a full fledged crush rolling.

It's the best method I've used bar using a guided diamond (one that's on a slide). I know what you're talking about on the star dresser. With the average star dresser it's hard to impossible to get a wheel really round. I have pretty good luck with my large one (which by the way would cost as much as the Crackerjack if bought new, mine came from a auction in like new condition for cheap). I've used star dressers that where so worn that it was totally impossible to really true a wheel.

Of course I'm sure you know that the proper use of a star dresser calls for the backing away of the rest and hooking the bottom of the dresser on the rest so you can lever it into the wheel. Not that I do it that way myself (to much time involved). I do set the dresser on top of the rest and press down pretty hard to prevent the jumping of the dresser .

When I first started using grinding wheels I was pretty young. I started working my dads old barn when I was around 8. My dad didn't have much of a shop out there. I was forced to gather up what tools I used. My first grinders where all just surplus motors with grinding arbors installed. The motors where invariably 1750 so where way to slow for proper wheel speed. My rests where always cobbled (when there was one). That was where I learned to grind with a wheel that was to soft and not get the wheel out of round (it's definitely a skill). I slowly improved my grinding setup through my teen years but never did have a really good setup till after I got out of the military and started my own shop. Even then in the early years the grinder I had didn't have as good a motor as it should have (It was a belt drive that I welded up and was a decent grinder if I'd put a better motor on it).

My current grinding setup is far superior. I've got a really old very well built 10" grinder that runs on 3 phase. It will coast for 15 minutes after turning it off (to give a idea of how smooth it runs). That is what I use for tool sharpening. I've also got a home made heavy duty grinder that came from my former employer. It's really old and heavy built. It can take up to a 16" grinding wheel but only at 1

There's also a really really old 18" flat face grinder. It's totally impossible to get wheels for it and the one that's on it is way to soft. I don't use it much but it's pretty handy for flat surfaces. I plan to one day make a platen to go on it so that I can use 20" sanding discs on it.

For a pic with the above in the background see here.

They seem to work similar to a brake controlled dresser like used on surface grinders (but I've never used one of those so can't say for sure).

Agreed. I have a hand held diamond dresser which I used for shaping grinding wheels when I was sharpening saw blades. It has it's uses but is dismal for bench grinder. It does do a decent job of truing a out of round wheel up but you'd better have something else to finish the job.

I know what you're saying but the wheels I have currently are really to soft for most of my work. But they where cheap so I'm using them up. I'm not real fond of a super hard wheel for large stock removal anyway. I do use a rest for this type work and years of off hand grinding experience allows me to keep a wheel running reasonably true. I do have problems when some of my help uses it though.

Based on what you've wrote in other posts I feel that I'm using the stick in the manner you describe. I figured out early on that presenting the flat surface to the wheel doesn't cut it. My original dressing stick that I got with my saw sharpening setup 20 years ago disappeared a while back and I got another which performs in the same way so I don't think it's the stick itself.

Agreed.

Thanks. I've not had much free time in the last year to do much posting.

I've used a carbide-tipped masonry drill to remove accumulations of soft metals from aluminum oxide wheels, where the doof that owned the grinder thought grinding wheels were high speed sandpaper. Soft metals, plastics, wood, rubber and anything else that needed "just a little more off".

The carbide tip will clear away the chunks of metal, but won't effectively clean the surface of the wheel. One needs to be prepared for and protected against flying bits of metal.

A follow-up treatment with a mounted diamond and a dressing stick is required to get the wheel to cut properly.

WB metalworking projects

I usually use one of those wheel dressing sticks. I call them a carborundum, but that probably a trade name. You know the look like a lava rock. I've used the soft white ones for cleaning diamond and CBN wheels. The star dressers....well I've got em but rarely use them. The norbide is great with fine wheels and for a little touch up. You can grind AL with aluminum oxide wheels but I always load them first with Beeswax, If I don't have any, I'll use crisco. I've even used bar soap if thats all I got. Some of the best cutting fluid for Aluminum is kerosine, but I rarely use it a mess and stinks. Mineral spirits works well also. Don't use the Kool tool stuff unless it's made for aluminum.

snip----

I fully agree that you can grind aluminum with an aluminum oxide wheel-----it just grinds better with silicon carbide.

Wheel loading was a serious problem for me when I ran aluminum through the centerless, which wouldn't have been fun trying to load with anything. We just struggled through the job----secure in the knowledge that it wasn't an every day occurrence. Had it been, we'd have changed wheels on the grinder.

Harold

If I don't have any, I'll use crisco. I've even used bar soap

I was at the local tool store and happened to see this:

This may not help in getting out aluminum. I think I would use a star wheel for that, and finish dressing with the diamond. ~~~~~~~~~~~~~~~~~~~~ DanG A live Singing Valentine quartet, a sophisticated and elegant way to say I LOVE YOU! snipped-for-privacy@okchorale.org (local)

IIRC, I paid ~$3.00 for one of those at Princess Auto about a year ago. I have not tried it yet (I just found it yesterday.) Gerry :-)} London, Canada

Cluster diamonds dressing tools. Not exactly a new innovation, and not the best solution to preparing a wheel for grinding offhand. Diamonds simply leave the wheel too smooth for effective hand grinding----although they are the very best for truing the wheel. For offhand grinding, a wheel dressed with a cluster, that is then slightly roughed with the proper dressing stick, will outperform a diamond dressed wheel. ALWAYS!

Harold