CBN Wheel -- 1 or 2?

[Jamie Straw]

I have birthday $$ for a CBN wheel, or two! It has been suggested that I buy only 1 CBN so I have a "normal" wheel for grinding things that shouldn't be ground on CBN. From what I've heard, a 180 grit CBN would serve for both sharpening and profiling. (Currently sharpening on a 120 grit aluminum oxide wheel and get good results) For those of you who have some budgetary constraints and only one grinder, what's your opinion?

[Roger Chandler]

I have both the 180 and 80 grit CBN wheels on my grinder. If I had to get just one, it would be the 180 grit. Moderate shaping can be done, on the 180, but it gives an almost polished surface on the gouge, and is plenty sharp for turning. Going up to 320 or 600 does not in my estimation give you much advantage as the keen edge will dull so quickly, it is not worth it. Richard Raffan told me he uses a 46 grit wheel for his turning gouges!

I do not have any high carbon turnng tools, and do have other grinders to sharpen knives, mower blades etc. A Norton. 3x blue wheel is about the best friable wheel out there IMO.

[Fred Belknap]

Jamie I have two CBN and I do most of my sharpening on a 180 grit. There is an 80 grit on the other side and it gets used mostly if I want to change a profile on a tool. I also use the course grit to grind carbon steel sometimes (not recommended) and it works ok. I have mine mounted on a cheap Woodcraft grinder 1/2 hp slow speed, it's been several years and it is still going.

[Joe Kaufman]

I had the 180 more than 3 before I purchased the 80 grit. So used to the 180 that I seldom use the 80.

[Peter Blair]

Jamie I think it depends on just how you plan to use your sharpening station. I have a high speed grinder for shaping and use 2 180 CBN wheels.
I have the Wolverine jig and use one side to quickly touch up my gouges and the other side has a Robo Hippy Jig to touch up all my angled tools such as skews, parting tools and with another jig all my small hollowing tips. I don't think I have seen a better set-up for the way I sharpen.

[Doug Ladendorf]

You might also consider the shape of the wheels and available working surfaces. A square sided wheel with some grit on the side may be useful for some things, a radius edge may provide use for others.

[Steve Peterson]

It depends on your usage. I keep a normal wheel on one side and a 180 grit wheel on the other. My normal wheel gets about the same amount of use as the CBN. I use the normal wheel for grinding soft iron on things completely unrelated to woodturning. If I was a professional woodturner, then it might be different.

Steve

[David C. Roseman]

Jamie, if you can only have the one grinder in the shop, one 180 grit CBN wheel on one side and your current 120 grit alum. oxide wheel on the other will cover your needs and give you the most flexibility. Because CBN wheels aren't friable, they will load up with steels that aren't M2 or better. You don't want to be completely without a way to grind lesser metal.

If budgetary constraint, rather than space in the shop, is the only issue, adding a second grinder doesn't need to bust the budget. Run down to HF and pick up an 8" conventional 3450 rpm bench grinder with task light for $45 on sale with a 20% coupon. http://www.harborfreight.com/8-inch-bench-grinder-with-gooseneck-lamp-37823.html They are actually just fine for general-duty grinding of beater tools, garden shears, etc. You can eventually replace the cheap OEM alum. oxide wheels with better ones, if you want.

Then, for your good turning tools and HSS chisels, you can dedicate a slow-speed (1725 rpm) grinder to two CBN wheels. I agree with Roger that 180 and and 80 are a nice combination. A slow-speed grinder is best for most of us when grinding good lathe tools, unless you have a really light touch and lots of experience. Doug Thompson grinds every tool he ships on a 3450 rpm grinder using Norton 3X K Grade alum. oxide wheels (46 and 80 grit), but he grinds for hours every day. :) BTW, if you haven't seen it, Thompson has a good sharpening video up on YouTube. https://www.youtube.com/watch?v=ttYyulsM7wg

Also, SMC member Reed Gray has written an excellent article on CBN wheels: https://www.robohippy.net/featured-article/

[John K Jordan]

I have birthday $$ for a CBN wheel, or two! It has been suggested that I buy only 1 CBN so I have a "normal" wheel for grinding things that shouldn't be ground on CBN. From what I've heard, a 180 grit CBN would serve for both sharpening and profiling. (Currently sharpening on a 120 grit aluminum oxide wheel and get good results) For those of you who have some budgetary constraints and only one grinder, what's your opinion?


I am also leaning toward the 180 and 80 grit combo. I currently have a 180 and 220 on one grinder and they are too close together in grit size. I may have too many grinders (5) and too many CBN wheels. Should I send you a grinder with a 220 wheel attached? Trade for three chickens and a hog or an old English saddle?

The 120 is fine for all of the profiling I've done on gouges but a bit slow on creating wide negative-rake scrapers from Thompson steel. This is with the wheel broken in - it was MUCH more aggressive when "fresh"!

My near-term plan is the Tormek with a 1000 grit wheel, two slow speed grinders with 600, 120, 80 and AlOx wheels mostly for lathe use and general shop use.

(The weld room has it's own bigger grinder - makes too much mess!)

JKJ

[Peter Fabricius]

I vote for a 180 CBN on the right side and a regular stone on the left.
Sharpen tools lightly on the CBN, it is aggressive and can waste a lot of tool steel if you GRIND it too hard.
Peter F.

[Mike Goetzke]

Jamie I think it depends on just how you plan to use your sharpening station. I have a high speed grinder for shaping and use 2 180 CBN wheels.
I have the Wolverine jig and use one side to quickly touch up my gouges and the other side has a Robo Hippy Jig to touch up all my angled tools such as skews, parting tools and with another jig all my small hollowing tips. I don't think I have seen a better set-up for the way I sharpen.

I don't have a ton of experience but I sold my Tormek and bought two CBN wheels. Mine are 180grit radiused & 350grit 4-in-1. Like Peter I have Robo jig on the 180 side and Wolverine on the 350 (they are fairly simple to swap). I wasn't very good with the Tormek but these CBN wheels allow me to spend much more time at the lathe. I really like the Robo jig for sharpening my fixed angle tools.

Mike

[Reed Gray]

Well, I used to say 80 and 180 for CBN wheels. If you are only getting one, I would say the 180. Since I get almost identical burrs for my scrapers off of both wheels, and they both create an excellent burr for my scrapers which I do my heavy roughing with, I am thinking that after having a 600 grit wheel for a couple of months, I really like it. It gives the burr for finish cuts, and the polished edge for finish cuts on gouges and even the skew. Those edges are not good for heavy roughing though as they fade quickly. Not sure about a 320 grit wheel. I do know that Dave Schweitzer can get wheels up to 800 grit. I have a 1000 grit wheel, and it is in test phase, but pretty much the fine wheels do power honing, and I don't think I ever did it right when doing it by hand because there is that much difference in the edges.

robo hippy

[Roger Chandler]

Reed, I have found that in some instances, on some forms, that I can get a surface finish off the gouge or scraper, that allows me to start sanding at 240 grit, and a few times 320 grit, and that is off the 180 grit CBN. That is with a shear cut with the wings, and the handle held low, and just the cutting edge working [floating the bevel] as Stuart Batty mentions, or with the scraper held at about 35 degrees for shear scraping.

At a higher grit like 600- 1000, I do agree it would be power honing basically......might be good for a skew, but I wonder about their benefits for most turners. Perhaps a highly skilled production turner might be able to realize benefits in their work, but the utility for the majority of turners might be questionable.

You deserve commendation for putting all this to research and exploring/pushing the envelope on this area..........perhaps you will discover through your research a means to eliminate most of the sanding we turners have to do now! :rolleyes: Well.......we can dream, can't we! I do appreciate your work in this area, and the way you are sharing your observations as you go through the experimentation process!

[Reed Gray]

Roger, it is all my dad's fault, he is an engineer who at age 93 still goes into work every day. "I am not going to retire till my birth certificate expires." The other one that applies here is 'if it ain't broke, take it apart and fix it anyway.' (author unknown). I have to experiment because of curiosity. We have all hear countless stories about how turners who have been using dull tools go wild with excitement when they finally turn with sharp tools. How sharp and how much of a difference does it really make is open for debate. For sure, many may not really appreciate or feel the difference, but they may figure out that some thing is different.

To me, the cleanest cuts come from two things, sharp tools and a high shear angle on the cut. Stuart and I are way apart on our views on scrapers. When I shear scrape, I am at a 60 to 80 degree angle. 35 just doesn't cut it to me. It is the speed bump thing. Hit the speed bump head on (scraping cut) and you get a big bump. Hit it at a 45 degree angle, still a bump, but much more smooth. Hit it at 80 degrees, and you barely feel it. He also claims that a shear scrape and a negative rake scraper are the same cut, or cut the same. To me, a scraping cut, with the cutting edge at 90 degrees to the rotation of the wood is a scrape no matter what tool you use or bevel angles. A shear cut or shear scrape, no matter what tool you sue is more of a slice and has less resistance than any scraping cut no matter what tool you use.

robo hippy

[Roger Chandler]

I should have said that I also use about a 45 degree angle to shear scrape as well, mainly on some woods that tear out is a bigger issue.......it takes longer to get it to smooth, but the 45 degree does work better than 35 degree on some woods/cuts. I do wish most tool suppliers had scrapers with rounded edges so that it would be easier to hold an angle than on that sharp 90 degree corner when a scraper is turned up to shear scrape.

[John K Jordan]

...
At a higher grit like 600- 1000, I do agree it would be power honing basically......might be good for a skew, but I wonder about their benefits for most turners. Perhaps a highly skilled production turner might be able to realize benefits in their work, but the utility for the majority of turners might be questionable. ...

For me, the finer grits really make a difference on smaller things with hard woods such as some exotics. The smoother the edge, the smoother the cut. If I sharpen a spindle gouge or skew at 600 I get a better surface on the wood than if sharpened at 220. Depending on my tool control that day a small spindle of cocobolo, dogwood, or ebony I might only use 800 paper or so.

I got used to polishing the cutting edge of my spindle gouges on the Tormek water wheel - a razor-sharp mirrored edge is a dream to use, just like with carving tools. Bigger things with coarser wood: the grinding grit doesn't make much difference.

I put a 600 grit CBN on the Tormek and while I like it, it doesn't give me the edge I got with the water wheel. I may try the 1000 grit.

JKJ

[Roger Chandler]

For me, the finer grits really make a difference on smaller things with hard woods such as some exotics. The smoother the edge, the smoother the cut. If I sharpen a spindle gouge or skew at 600 I get a better surface on the wood than if sharpened at 220. Depending on my tool control that day a small spindle of cocobolo, dogwood, or ebony I might only use 800 paper or so.

I got used to polishing the cutting edge of my spindle gouges on the Tormek water wheel - a razor-sharp mirrored edge is a dream to use, just like with carving tools. Bigger things with coarser wood: the grinding grit doesn't make much difference.

I put a 600 grit CBN on the Tormek and while I like it, it doesn't give me the edge I got with the water wheel. I may try the 1000 grit.

JKJ

John, I would agree with dense woods like exotics that a polished edge would make a better cut than without a polished edge. My frame of reference in my comment was basically turning bowls, but you certainly make a valid and a good point here. Especially with the skew, detail gouges and working spindles out of exotics which are dense. Finials are a classic example of this.

[Jamie Straw]

Thanks so much for all of the information! I'm ordering one 180 grit wheel soon, and got some good ideas from your posts. Feel good about the decision -- the reason it was important is that the price for 2 is $50 of buying them individually, but I think it'll be easy to live with just one.

[Curtis Myers]

Mine are 180 grit radius & 350 grit 4-in-1. Like Peter I have Robo jig on the 180 side and Wolverine on the 350 (they are fairly simple to swap). I really like the Robo jig for sharpening my fixed angle tools.

Mike


I have the exact setup. Work well for me.


339139

All the Best
Curt

[Jamie Straw]

Oh joyful day. As I was filling out the online info to order the 180 grit CBN "birthday wheel" from Ken Rizza, Stevie Ray Vaughan's "Pride and Joy" was kickin' out from the boom-box. Almost started dancing! Next week, I'll be in sharpening heaven, methinks. :D:D

[Jamie Straw]

I have the exact setup. Work well for me.


339139

All the Best
Curt

Yep, I'd like to get the Robo Rest some day. Have liked it since the first time I saw it in one of Schweitzer's videos -- "This guy down in Oregon sent me this....":)

[Reed Gray]

I do miss SRV.... Love Lenny, and his version of Little Wing, and others..... Dance to the Music... 3 Dog Night? Yup, went and looked it up, some times the memory cells do function... Now back to practicing Little Wing..... Been working on Lenny for 5 or 6 years... Freddie King is a little bit easier... Jeff Beck, not even in my dreams...

robo hippy

[Kyle Iwamoto]

Jeff Beck Constipated Duck........

[Doug Ladendorf]

I always thought there should be a compilation album of everyone's version of Little Wing. That would be cool.

[John K Jordan]

I do miss SRV....

A good friend of mine near San Diego put together a Stevie Ray Vaughn tribute band, has been performing 15 years or more. Alan is quite serious about this - he even traveled to Texas, I think, to have a hat made by Stevie's hat maker! I did a pr photo shoot for him once at a concert. It was loud. :)

http://www.alaniglesias-and-crossfire.com/

https://www.youtube.com/watch?v=aQ75FU-LWbo

JKJ

[Reed Gray]

One of my most favorite versions of Little Wing:

https://www.youtube.com/watch?v=HhsacepElvA

These girls.... Sigh!

robo hippy