Another CBN Question...

[Tom Albrecht]

It seems that with the advent of the CBN wheel there are ever more finer and finer grits available. I apologize if I am resurrecting an already covered topic. In regard to CBN wheels, regardless of manufacturer, and only concerning grit #:

• I am curious to know what most folks are using as a finishing wheel for gouges, as in all gouges (bowl, spindle, detail).

• I am also curious to know what most folks are using as a finishing wheel for scrapers.

 

[hockenbery]

I'm using an 80 and a 180
I use the 80 for my Ellsworth bowl gouges
The 180 for spindle gouges, detail gouges scrapers, and my 1/4" bowl gouge with the micheslson grind. The scrapers I usually finish with a diamond hone to strike a fine burr.

Skews I sharpen on the tormek.

 

[john lucas]

I have the 180 and use it for most things. I still have an aluminum oxide 120 on the other side for carbons steel tools and I think it raises a better burr on some of my scrapers.

 

[Gerald Lawrence]

I use a 180 for all gouges . Use an 80 for my scrapers adn sometime burnisher for the burr. However Robo has gone up as high as 600 and I believe he said the results are better for his scrapers.

 

[Zach LaPerriere]

I don't use scrapers much at all...very soft Alaskan woods.

And now a caveat that I'm a nut and most people here may find my process excessive and unnecessary, but I sharpen for the best finished surface because I turn softer woods and sanding drive me crazy. My process has evolved from the normal 80 and 180 CBN wheels to ever sharper, then back a little from 1000 to 800.

In the gouge department, I sharpened to 1000 on Ken's wheels until about 6 months ago, but I now find that I get a sharper edge on Dave's 800.

I use the 80 to grind the heel way down, the 180 for rough turning, the 400 for finish cuts, and the 800 for final finish cuts. Since I sharpen with a modified version of the Michaelson grind, the 400 and 800 wheels only ever sharpen at most an 1/8" of bevel.

I mostly just use bowl gouges, but I use the occasional spindle gouge. I generally just turn bowls.

I also hone between sharpening on final finish cuts. I used to hone the bevel with Craft Supplies' 800 CBN hand slipstone, but I switched to a Spyderco ceramic slipstone that is roughly 4000 but still fairly aggressive.

I don't own a Tormek, but my impression is that the Tormek leaves an edge that is effectively sharper than 800 or 1000 CBN. I've stuck with the CBN wheels because 1: I at least think it's faster, and 2: I turn in an unheated space that frequently freezes for 5 or 6 months of the year.

 

[Tom Albrecht]

Zach: Correct, you are a nut. How many grinders do you have man? That's a lot of wheel changing.

Anyhow, it's only "excessive and unnecessary" if all those who think that way can get better results with less excess.

 

[Zach LaPerriere]

Just two grinders, Tom, and though I own more, I only regularly use those 4 wheels: 80, 180, 400, and 800.

I have enough bases to not be swapping things around.

 

[JoHannes Michelsen]

I started with CBNs 5-6 years ago and I've had the same 180 on my go to working grinder all that while it is now acting more like 300 maybe 400 and I'm good with that it produces a very polished surface also good with that . I now stock 360 grit and will try one one day but right now I feel like Im already there.
I'm not a wire edge believer they never were any good just not reliable at some point they fall off then you are left with a semi sharp tool, a truly keen well shaped shard edge is way superior and way more reliable and durable. The old stone wheels did "good" wire edges because they were about half cut half friction ---heating--- and pounded the edge into submission.
All very un predictable --not good!

 

[RichColvin]

I use the Tormek for all sharpening. For most lathe tools, i use the black stone (SB) wheel graded roughly (220 grit).

When I get to the finishing cuts when I grade the stone smoothly (1,000 grit) and hone the tool on the leather wheel.

For skews, when using them on hard woods (e.g., ash), I have found using the Japanese waterstone (SJ) with a 4,000 grit to be quite useful. The finish it leaves is amazing.

 

[robo hippy]

80 and 180 will both work very well for heavy burrs for scrapers and heavy stock removal. I do prefer the 180 for most of my gouge work. I haven't tried any others up to the 600. The 600 and 1000 grit leave excellent burrs for very fine finish cuts on shear scraping, and very fine edges on gouges for fine finish cuts, but don't leave a very durable edge for heavy roughing. Easier than hand honing to me, as they seem to work better than my hand honing ever did, but that could be me....

robo hippy

 

[Raul McCai]

• I am curious to know what most folks are using as a finishing wheel for gouges, as in all gouges (bowl, spindle, detail).

• I am also curious to know what most folks are using as a finishing wheel for scrapers.

Well I was at my mill supply and they had two 10" wheels: fine and coarse. I liked 'em. So I got both and that's what I use. Being an old machine tool guy I paid no attention to the grit denominations and relied on my fingers to tell me what I needed.

 

[john lucas]

Doesn't it hurt to touch that spinning wheel.

 

[Tom Albrecht]

So I have decided that part of my issue with the CBN wheels I use is that I have the ones with rounded edges (thank you David E.) Though I may have a 1 1/2" wheel, I really only have a 1" flat face to work with for typical grinding needs. For me, it is deceiving to look at the entire spinning wheel width, but in fact, only have 1" to grind on, not 1 1/2". This may easily be a problem peculiar to me and my age, but I am switching to non-radius 1 1/2" wheels to prevent the "falling off" that I tend to do whilst sharpening a gouge held in a jig.
And I am going 80 and 180 grits.

 

[hockenbery]

The rounded edges, I find useful for sharpening hollowing tools, definately reduce the useable width of the wheel.

I like/ need the sharp corner edge for sharpening some tools like a box scraper.
I cannot sharpen a spur drive on the radius wheel.

I keep a second grinder with the norton wheels with a sharp corners.

 

[john lucas]

I also like rounded corners for sharpening hollowing cutters. I don't have that on my CBN. Oneway Wolverine jig came out with the new model to prevent people from running off the edge of the stone. I' have never had a problem. I just take my time moving the tool back and forth across the stone. Before I got my CBN which is 1 1/2" I had been using a 1" white wheel. I have had students run off the stone which is I guess why Oneway came out with the new jig. It keeps the tool centered but of course wears the wheel unevenly. I prefer to use the full width of the wheel to keep wear across the wheel the same.

 

[hockenbery]

What I do with beginning students is have them practice the sharpening motion with the jig with the contact point in the center of the wheel with the grinder not running. I stress keeping the tool moving and keeping the contact point in the center of the wheel. A couple of times through the motion builds muscle memory.

Then I bring the grinder up to speed and turn the grinder off. As soon as the power is off the students grind both sides of the gouge and the nose working in the center of the wheel.
The students feel a little more confident knowing there is no power and they learn not to press too hard. I just stress staying in the center of the wheel that way if they get off a bit there is still plenty of wheel. I repeat thengrinding with no power until they have it. Twice for most and 3 times for a few. Then I have them sharpen with the grinder running.
When they do well I authorize them to sharpen on their own. If I have any droughts I ask them to have me watch when they sharpen their second time. I've never felt had to watch a student a third time.

Maybe the little groove that would develop in the center of the wheel helped keep the tool in the center. Also once the groove got bad some people would try to use the 1/4 flat on either side and get into trouble instead of dressing the wheel.