Intro to CBN wheels - a few questions

[Steve Mathews]

I stated earlier that I wasn't going to get a CBN wheel at this learning stage of mine but a few things have since changed. So at this point I would like to buy one but which one? Here's a list of limitations I've placed on my selection process, the rest are up for grabs.

8" wheel
1" arbor hole size with capabilities to bust down to 3/4", 5/8" and 1/2"
1" wide wheel ( I would like to still use the shroud if possible.)

Here's what I haven't decided upon and would appreciate comments or suggestions.

Aluminum or steel wheel
Rounded or radius edge

I understand one of the benefits of the CBN wheel is that more heat is absorbed by it than a standard grinding wheel. So wouldn't aluminum be better because of its greater thermal conductivity?

[Roger Chandler]

The Hurricane CBN wheels come in various widths, and he has them as a direct bore for the arbor size on the grinder you have.......5/8, up to 1". That eliminates the need for a bushing , and makes the wheels run all the more true. I have both the 80 grit and 180 grit on my grinder, and they are top notch equipment. The price is much less than many others out there, yet the quality is outstanding. I have the 1.5" wheels on my grinder as the arbor length will accommodate them and I have the power in the motor as well.

http://www.thewoodturningstore.com/products/Hurricane-8-CBN-Grinding-Wheels-180-Grit-1-Wide-732.html?cPath=62

[Dale Miner]

The Hurricane CBN wheels come in various widths, and he has them as a direct bore for the arbor size on the grinder you have.......5/8, up to 1". That eliminates the need for a bushing , and makes the wheels run all the more true. I have both the 80 grit and 180 grit on my grinder, and they are top notch equipment. The price is much less than many others out there, yet the quality is outstanding. I have the 1.5" wheels on my grinder as the arbor length will accommodate them and I have the power in the motor as well.



http://www.thewoodturningstore.com/products/Hurricane-8-CBN-Grinding-Wheels-180-Grit-1-Wide-732.html?cPath=62


Methinks the $7.49 price is a huge bargain, but also think it is a misprint.

[Michael Schneider]

I have wheels from 2 makers and they both do a good job

d-way tools make a great cbn wheels with 1" + adapters. http://d-waytools.com/cbn-grinding-wheels. They are steel wheels and very nice.


Woodworking wonders do a very nice lighter http://woodturnerswonders.com/collections/cbn-wheels. It is drilled to a specific arbor, but you could have it drilled out to a larger arbor later (if you plan on going up in size).

d-way has 80 and 180 grit
woodworking wonders has many different grits.

There are multiple threads on first one. A 180 will shape (albeit slowly), and put a nice edge. After using the 180 for awhile, you can decide if you want to go to a finer grit or a courser grit for the second one (if you want 2).

[John K Jordan]

8" wheel
1" arbor hole size with capabilities to bust down to 3/4", 5/8" and 1/2"
1" wide wheel ( I would like to still use the shroud if possible.)
Aluminum or steel wheel
Rounded or radius edge


Steve,

Ken Rizza mentioned he went with aluminum partially because of the heat conductivity. Another reason was weight.

I'd also probably start with a 180 grit wheel then add others later. At the moment I have 80, 180, and 600. All these wheels are square edge wheels for 5/8" arbors, 8" diameter and 1.5" in width (except a 4th wheel for the Tormek is 10"x2".)

I initially bought one with radiused edge but eventually replaced it with the square edge. I also get the type with 1" of grit down the flat on both sides. Two reasons: one, the square edge with the flat side gives me more grinding options for shaping and sharpening special tools. Second, the radius takes away from the usable flat width if you are grinding with the straight portion. I didn't measure, but I think you lose 1/4" on each side.

The radiused edges are nice for grinding curved scrapers and small hollowing tips IF what you are sharpening has a long handle. A long handle makes it awkward to swing the tool to sharpen the curve but the radius lets you simply push the tool across and around the edge. For my turning, the lack of a radius is not an issue.

Consider simply removing the guard from the grinder. Unlike a friable stone wheel that can shatter and throw deadly chunks, the solid aluminium/steel wheels will not. The hazards of getting sleeves caught or arms cut while reaching over the spinning wheel remain, but someone prone to do this might consider taking up another hobby. There are occasional sparks but compared to stone wheels the sparks are nothing. Safety glasses should always be worn, of course.

If you find a 1" wheel with radiused edge the flat portion in the middle will be very short. I don't think I would like that.

Also, I think I mentioned this before, but I have become a believer of using Rizza's spherical washer sets. Some grinders have lower tolerances on the nuts and washers/flanges and the wheel may not run true. (Unlike stone wheels, truing is not possible!) I used the washers on 5 CBN wheels and every one runs true.

I personally would have a wheel made for my exact arbor size rather than try to make a bushing work.

JKJ

[Doug Ladendorf]

Steve, if you want to keep the guard you can make a spacer for between the inner guard and the outer cover. There are some examples here on the forum. What grinder are you using?

[Tom M King]

340129bushings don't matter. This one is running some bronze bushing I ordered off the internet for about a buck. The Metabo needs a long bushing that goes up inside the motor housing. It's been long enough ago that I don't remember the exact details, but it was an oddball. You can see that it has no effect on smoothness, although I can see the possibility if one was made poorly.

Also, there is no need for a shroud. I lay a wet paper towel under the wheel to catch the swarf.

I bought the radiused wheel, and don't remember using the curved edges. If I did it over, I'd just get a flat one.

It's not that the wheel absorbs the heat. It cuts so fast that there is no time for friction to create the heat we know from friable wheels.

[Steve Mathews]

Steve, if you want to keep the guard you can make a spacer for between the inner guard and the outer cover. There are some examples here on the forum. What grinder are you using?

Sort of undecided which grinder to use at this point. In the beginning I was struggling to find a grinder for all of this but just one day after purchasing a Baldor 8" slow speed grinder I came across a Jet 10" slow speed grinder at a garage sale. Not being able to turn down the offer I now find myself with both as candidates. I like the idea of using the Jet with its larger motor and 1" arbor thereby eliminating a bushing for some of the CBN wheels. To further complicate matters the seller of the 10" Jet threw into the sale an older Jet 8" grinder but it operates at the higher 3450 rpm. It has a 3/4" arbor, the same as the Baldor. (Note: Jet apparently reduced the arbor size of this same grinder in later productions.)

There seems to be a compelling case for using 1 1/2" CBN wheels and I suspect they will not fit into any of the grinder shrouds, at least based on the ones I have, which are only 1 1/2" wide. So it looks like I'll have to remove the shrouds and run the CBNs bare unless one of the examples that Doug mentioned suggests otherwise. I hope to make a decision as soon as possible so I can order at least one wheel early next week.

[Reed Gray]

The main reason to keep the shrouds on is for dust control. The metal dust will float in the air like wood dust. I keep the inside ones on and don't use the outside ones. You can make an outside shroud space block of some sort without too much trouble. Biggest reason for me to get the 1 1/2 inch wide wheels, I have never run off the edges of the wide wheels with my gouges and put that huge groove into them like I did with the 1 inch wide wheels. If you get one wheel, get a 180 grit. 2 wheels, I used to suggest an 80 grit which does a better job of shaping tools. Now you may want to consider a much finer wheel. I have a 600 grit that I love because it makes a better edge for finish cuts and for shear scraping burrs. I also have a 1000 grit wheel which is still undergoing 'testing', but the burrs and edges from it are also very fine, which means good for finish cuts, not so good for roughing cuts.

robo hippy

[Robert Willing]

Will these grinding wheels grind any gouge material or are they only meant for none HHS steel?

[John K Jordan]

Will these grinding wheels grind any gouge material or are they only meant for none HHS steel?

I use mine for every turning tool. I understand they are designed to be used for any hardened steel: carbon, HSS, 10V powerded metal. Apparently softer metals like non-hardened mild steel will clog them. Mr Reed Grey has a good article:

http://www.robohippy.net/featured-article/

I keep a separate grinder with aluminum oxide wheels for grinding mild steel.

JKJ

[David C. Roseman]

340129bushings don't matter. This one is running some bronze bushing I ordered off the internet for about a buck. The Metabo needs a long bushing that goes up inside the motor housing. It's been long enough ago that I don't remember the exact details, but it was an oddball. You can see that it has no effect on smoothness, although I can see the possibility if one was made poorly. [snip]



Have to disagree with you, Tom, that bushings don't matter. Glad your setup is running true, but I think you may have gotten lucky with your $1 bushings.

[John Grace]

In the for what it's worth category. I recently acquired my first two CBNs, and frankly, wished I'd done it much sooner. I think one of the phenomenons of woodworkers and turners in particular is we more readily acquire tools as opposed to something bland like a sharpening mechanism. That said, I purchased both a 180 and 350 grit wheels...using the 180 for general tool shaping and my scrapers and the 350 for final gouge sharpening. Both are from Wood Turner's Wonders and the edge they put on my tools is nothing short of fantastic. Basically...I learned the valuable lesson that a sharp cheap tool is far better than a marginally sharp good tool or even the purchase of a new tool.

[Reed Gray]

They are for 'hardened' steel or metal, so bench chisels are fine, but softer metals like old carbon steel can and/or will clog up the wheels. You can get away with it once in a while, but I would not do it on any regular basis. The more standard aluminum oxide wheels or the blue ceramic wheels work better for that material. Clean up with a good HSS scraper, sharpening as usual. Some Trend lapping fluid also helps to keep the wheel clean.

robo hippy

[Joshua Dinerstein]

Some Trend lapping fluid also helps to keep the wheel clean.
Robo Hippy,

A very interesting thought using the Trend lapping fluid. I have a big bottle of it that I bought for using on my flat hones. And 2 years and about 5-10 drops later it would seem I have purchased a lifetime supply of it. :)

How do you apply it to the wheels? How do you keep it from spraying everywhere once you turn the grinder on?

Having seen how well it works on a flat hone I would be very interested in seeing how it works on a CBN wheel once I actually get one installed...

Thanks Reed!

Joshua

[Reed Gray]

First efforts were to dribble a few drops on the wheel, smear it around with my fingers, then turn it on. I did get sprayed a few times. Now, I do hone off the burrs on my scrapers before grinding a new one on, and put the trend on the hone, then grind. That seems to be enough wetness to color the wheel slightly as there is some on the bevel when I do scrapers. I am thinking a small paint brush would do an excellent job as well.

robo hippy

[John K Jordan]

First efforts were to dribble a few drops on the wheel, smear it around with my fingers, then turn it on. I did get sprayed a few times. Now, I do hone off the burrs on my scrapers before grinding a new one on, and put the trend on the hone, then grind. That seems to be enough wetness to color the wheel slightly as there is some on the bevel when I do scrapers. I am thinking a small paint brush would do an excellent job as well.


I bought some after you mentioned it and tried a couple of things. I want to try putting it in a bottle and spraying a shot of fine mist on the wheel as it is turning. That works well with water when I wet sand acrylic.

JKJ