CBN Wheel Question(s)

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Warren White

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Aug 27, 2014
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Livermore, CA
I searched the forum and yet I still have a couple of questions.

My mentor and friend, with whom I share sharpening tools and fixtures (and many hours turning), was sharpening on his standard white wheels (with a Rikon slow-speed grinder) when something happened and the wheel fractured. Thankfully, even though it was VERY scary, he was not injured. He wasn't wearing safety gear at the time, which is a lesson-learned for both of us and perhaps others on the forum. The grinding wheel has a small chunk missing and is of course unusable.

We are looking to replace the wheel with a CBN wheel, and have a few important questions.

First, given the weight difference, can we just buy one CBN wheel or must we replace both of them?

If we can get by with replacing just one, what grit do you recommend?

If we need to replace both, what grit(s) do you recommend?

Second, do you have recommendations of which CBN wheel we should buy? (And as important, which ones you would not recommend.)

Thank you very much. Your comments are most welcome.
 
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tonylumps

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Nov 7, 2016
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newtown square pa
I have been sharpening my own tools for a long time with a Tormek wet grinder.But it did not take me long to switch to a low speed grinder with CBN wheels.The HSS tools were just taking to long.The pluses to a CBN wheel are they last a life time,are perfectly balanced and stay cool when sharpening.The bad is that you could only sharpen HSS.No carbon steel.Like knifes or wood chisels.You can touch up Carbide turning tools if you have a jig for the cutters themselves.As far as running one wheel.Yes works great because they are balanced.I did it for a Month before I had the money to buy the second.The first wheel should be 180 Grit for sharpening and touching up.The second wheel i bought was 80 Grit for a little reshaping.Wood Workers Wanders have a very good price on single wheels and a Low speed Grinder and wheel package
 
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randyrls

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We are looking to replace the wheel with a CBN wheel, and have a few important questions.

First, given the weight difference, can we just buy one CBN wheel or must we replace both of them?

You can just replace one wheel. That is the setup I have on my grinder.

If we can get by with replacing just one, what grit do you recommend?

The higher the better. 220 or 320 will give a smoother finish to your tools. I have a 180 grit CBN and wish it was a higher grit. Just use a coarse (60) grit gray wheel for rough sharpening and to reshape tools.

If we need to replace both, what grit(s) do you recommend?

I don't recommend you replace both wheels with CBN wheels. The coarse gray wheel can be used for general sharpening, but the CBN wheel should ONLY be used for HSS tool sharpening. Use the gray wheel for lawn mower blades, and general sharpening.

Final thought: The CBN wheels are MUCH HEAVIER that the standard wheels and will spin FOREVER after you shutoff your grinder. Because they are heavier, any vibration problems in your grinder will be much worse with a CBN wheel.
 
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magpens

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Thanks for your comments, Randy. I am in the market for CBN also.

It's especially good to get your grit recommendation.
 

Charlie_W

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I also have one CBN wheel (180G) on a Rikon 1/2HP low speed grinder. Runs great. I did adjust the stock white wheel for less vibration. Sometimes I will give the grinder a spin by hand before flipping on the switch. A 1HP grinder would have more start up torque.
I have a flat 1.5" wide wheel. I do not see the ones with the radiused edges as being useful for me. I prefer to have the full width grinding surface. The wheel does have some abrasive surface on the side of the wheel. This edge is very good for putting a flat grind on a skew.(great for beginners)
 

jttheclockman

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Certain grinders the addition of a CBN wheel may cause the grinder to not start spinning because of the weight. Some people start by spinning by hand.

My question would be what caused the wheel to break??? Before putting any stone wheel on a grinder you should do the ring test beside give them a true looking over.

There is alot more to grinding wheels than what gets reported and known. here is a very good summary and a lot of info that may be helpful to others.


GRINDING WHEEL and ABRASIVES BASICS
 

Martin G

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Jul 19, 2011
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Austin, Texas
I have a related question. Are all turning tools HSS? I have some that are marked and some that are not. I haven't tried sharpening the unmarked ones on the CBN wheel. Should I?
 

Robert Taylor

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If they are not marked the are probably carbon steel. Do a "spark" test on a stone wheel. Carbon steel will give a spray of yellow sparks. Kinda like a sparkler on the 4th of July. High speed steel will give more of an orangeish spark in a single line that will follow the wheel and come over the top of the tool.
 

randyrls

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If they are not marked the are probably carbon steel. Do a "spark" test on a stone wheel. Carbon steel will give a spray of yellow sparks. Kinda like a sparkler on the 4th of July. High speed steel will give more of an orangeish spark in a single line that will follow the wheel and come over the top of the tool.

Yes; Search on YouTube for "Spark test" to see an whole lot of videos.
 

KenV

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I have been running Ken Rizza (Woodturning Wonders) CBN for a couple years. Using a slow speed 1/2 hp grinder. I am currently running 180 and 600 grit.

CBN is good for hardened steel, and not good for soft steel. Hardened steel includes high carbon steel like plane blades and chisels. Not lawn mower blades, etc. Keep a gray wheel for trash grinding. Keep the guards with the gray wheel too. (I actually use a hand powered grinder for the occasional trash grinding, or an angle grinder for the lawn mower blades)

High grit number CBN is a lot different and point one towards a lot less sloppy sharpening.

A 1 hp grinder is better if starting out. If you have 1/2hp, it works OK
 

Warren White

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Livermore, CA
To all who have commented / added to this thread...

I know I haven't responded to let folks know what I have done regarding my initial post. Events took place out of my control, but now I can get those interested up to date.

I did quite a bit of research and settled on buying through Ken Rizza of WoodTurnersWonders. He has been most helpful and understanding. The delay was caused by his being out of stock on at least one of the CBN wheels I needed. As soon as they arrived, he sent them out.

My friend decided he would buy a 350 grit CBN wheel to replace the oxide wheel that failed. It came first, and my friend installed it on his 1/2 HP Rikon. He called me and said "I am disappointed!" I was really concerned because he bought the wheel largely on my recommendation. I asked him what disappointed him and he responded "I am disappointed I didn't do this a long time ago!" We were both VERY pleased with the edge that was produced on the system (Rikon grinder and the Wolverine system).

I purchased a 1 HP Rikon with a 350 grit and an 80 grit wheel from Ken. After it arrived, it took a number of trips to Lowes/Home Depot to get all the right nuts, bolts and screws to assemble the Wolverine system, but we 'got her done' as they say. There is a little runout issue on the 350 grit wheel, but it seems to be the washers that came with the grinder/CBN package. Even with the runout, the results are spectacular!

Ken is VERY helpful and even answered some questions while he and his truck were going through a car wash! I would not hesitate to recommend Ken and the CBN wheels and the Rikon grinder I purchased.
 
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