CBN wheels

[Mike Walsh]

I know there are a number of posts on the site on this general topic, but I haven't been able to find "the answer" to my question. I'm a hobbyist who mostly does non-turning projects, but also like to spend time on the lathe (mostly bowls) to mix things up. For sharpening, I hollow grind chisels, irons on a Rikon low speed grinder and finish on water stones - use the same grinder with the Wolverine jig for turning tools. I'm thinking of upgrading to CBN wheels on my grinder. From what I've read/watched, it seems like the 180 grit CBN wheel will handle most all of my hollow grind needs as well as routine sharpening of the turning tools. It may be a little "light" for changing profiles on turning tools, but that's not something I do very often.

Am I on the right track with the 180 grit? And any thoughts grit choice for a 2nd wheel?

Thanks,
Mike

[roger wiegand]

I use a 180 CBN for turning tools, it's great. I'll touch up a skew with a slipstone, but otherwise the 180 is the only thing I use for turning.

There are warnings against sharpening softer steels on CBN, apparently non-HSS can clog the wheel. I sharpen all my hand tools and plane irons on waterstones now, so haven't put them on a powered grinder for a long time. I used to think a hollow grind was important, but my current system is so quick and works so well that I gave up that idea.

[Phil Mueller]

Stumpy Nubs has a YouTube video called ”How I changed my grinding forever” or something like that. He recommends 180 grit and 600 grit wheels for edge tools and carving tools. He finishes on 1000+ stones. Search on YouTube for CBN wheels and you should be able to find the video...which grits to use starts at about 6 minutes in.

I don’t carve, but I use a 180 grit for edge tools, then finish with finer stones. The 180 works pretty fast. I’m thinking of selling my 80 grit(which I got thinking I would need it to rehab old irons), and replacing it with a 600.

[Derek Cohen]

I wrote about this a few years ago when I was one of the early flat wood supporters. It was a revelation on two levels - firstly, that these wheels were to be a game changer, and secondly that this appeared to be a closely guarded "secret" in the turning fraternity for over a decade!

The article: http://www.inthewoodshop.com/Woodwor...ningSetUp.html

Regards from Perth

Derek

[Tom M King]

I don't think you'll find a 180 to be too "light".

[Mike Walsh]

Thanks very much for the quick replies!

[Prashun Patel]

I do exactly what you are thinking. 180 is not light. You can change flat or turning blade profiles quickly. It’s more aggressive than you would think.

[Edward Weingarden]

I'm a woodturner and put a 180 grit CBN on my grinder about three years ago. What a dramatic improvement. I left a 120 grit white aluminum oxide on the other side of the grinder to reshape tools and put a burr on my scrapers. I recently decided to put a second CBN on the grinder and went with a 350 grit. Since I don't do much reshaping of tools, I really didn't have the need for an 80 or 120 grit wheel. The 180 is good for putting a burr on my scrapers and puts a good edge on my gouges for initial shaping. The 350 puts a nice edge on for finishing cuts, without it being too fragile. There's an article on the topic of CBN wheels and the choice of grits in an issue of American Woodturner (publication of The American Association of Woodturners). If you send me a PM with your email address, I can send you the article.

[John K Jordan]

It might depend on what kind of finish you like on your turning tools. For bowl gouges, 180 may be fine. I prefer a finer wheel so I use a 600 grit for my skews and scrapers and a 1200 grit CBN on a Tormek for my spindle gouges. I also have a 180 grit CBN on one grinder but it's too coarse for my tastes. On the other hand, 600 is way too fine for reshaping large scrapers and such so I also keep an 80 grit CBN wheel just for that. (Between the 80 grit and the finer wheels I rarely use the 180 grit wheel) This may sound excessive but it works for me. Of course I hone and strop my tools too so that might tell you something...

Note that whatever wheel grit CBN you buy, it will be quite aggressive at first but settle down to it's longer-term behavior after a few weeks of use.

If possible, you might want to find turners in your area (through a local turning club?) with various well-used CBN wheels and try sharpening a couple of your tools and see if you like the result.

JKJ

[Jon Nuckles]

I have a 180 grit CBN and a 220 grit (IIRC) blue wheel on my grinder. I use the CBN for turning tools and any other HSS tools I might have. I use the blue wheel for chisels, plane blades and other softer steel. My CBN wheel came with a caution that softer steels than HSS will load the wheel. I haven't tested that caution. On the turning forum, I believe that Robo Hippy has posted that softer steel will load the wheel, but that sharpening HSS will clean that off in time. A search should turn up his posts. If you do use a 180 grit CBN wheel to change an angle, I think you'll find that it will remove material faster than an equivalent grit of a non-CBN wheel.

[John K Jordan]

Just to be clear you can grind any hardened steel (even if its not HSS) with the CBN but mild steel, aluminum, or brass will load up the wheel. R. Hippy said he ground a big scraper to clean the wheel.

I have a 180 grit CBN and a 220 grit (IIRC) blue wheel on my grinder. I use the CBN for turning tools and any other HSS tools I might have. I use the blue wheel for chisels, plane blades and other softer steel. My CBN wheel came with a caution that softer steels than HSS will load the wheel. I haven't tested that caution. On the turning forum, I believe that Robo Hippy has posted that softer steel will load the wheel, but that sharpening HSS will clean that off in time. A search should turn up his posts. If you do use a 180 grit CBN wheel to change an angle, I think you'll find that it will remove material faster than an equivalent grit of a non-CBN wheel.