CBN Wheel Grit Recommendations

[Chuck Barone]

I am going to change over to CBN wheels for my grinder. Ken Rizza of Wood Turners Wonders has recommended for me an 80grit for reshaping and scrapers and 350 or 600grit for regular sharpening. Two local turners have said that they were unhappy with the 350 because they thought it was too fine a grit and that 80 grit too course and recommended going with a 180grit. In reading this forum although grit recommendations are all over the place there seems to be a more of consensus leaning towards Rizza's recommendation or every higher grits up to a 1000grit.

1. CBN wheels have been around for a while but it seems that the finer grits are a more recent?
2. Can you compare grits across different manufacturers?
3. Are there pro's and con's of using finer grits?
4. Are there pro's and con's of using 80 vs 180 grits for reshaping/scrapers?

Appreciate any help sorting all this out! Thanks! Chuck

 

[Zach LaPerriere]

Here are my experiences:

1. Finer grits have been around, but are gaining traction.
2. To a certain extent yes...but my experience is that Dave of D-Ways cut better and clog slower than Ken's. I tried an 800 from Dave a year and half or so ago, and abandoned my 1000 from Ken. The 800 got things sharper.
3. For finer grits, you can't realistically sharpen the whole bevel. It's just absurd to try to remove all that steel with a 600 to 1000 grit wheel. The simple answer is to grind a secondary bevel with a course wheel and leave a small bevel that you sharpen at fine grit. Please note that I can't really comment on this for scrapers...I regularly only use a scraper for dovetail tenons.
4. For reshaping and sharpening rough turning gouges, I prefer my 60 grit to an 80 grit. I talked with Dave about going courser, but he felt there's a limit at which the grit particles are just too big and become ineffective.

Good luck!

 

[john lucas]

I just upgraded from 180 to 360. I do use a short main bevel and then grind a secondary bevel. I have been testing the higher grits using a strip sander and like 360 better than the higher grits although 600 wasn't bad. 80 for rough shaping although I use another grinder with a really course wheel to rough grind things. The CBN wheels remove metal fast enough that I can final shape the edge with my finer wheel. I ground a carbide cutter in half to see what it looks like using my 180CBN and I think it now cuts finer than the 360 but we will see once the 360 breaks in. They always cut courser when they are new.

 

[William Rogers]

I just bought a new 180 grit wheel from Ken. My old 180 grit was a steel wheel from the Woodturning Store. I have used it for 5-6 years. I think now it is more like a 350 grit. For reshaping I just put my 60 grit white wheel on as for that I can't justify the cost. If I want a "finer" surface I have a leather belt and use honing paste, but mostly just go from the grinder using the older wheel for final cuts and the newer wheel for non final cuts.

 

[robo hippy]

Well, if you are getting only one wheel, get a 180 grit wheel. I don't think the 80 grit is necessary unless you want one of every thing. They are good for moderate reshaping, but if you are doing much, then you need a 36 grit wheel or belt sander. As for how fine, well, I don't really know how much difference there is between 360/400 (don't have one, at least not yet...) and the 600 grits. For sure the 600 grit wheel for me is better for a fine finish cut edge but not for a good roughing cut edge or for making a big burr. I probably need to get a 180 from Ken to test drive it. I have never really heard of a comparison between the two, but for sure, Dave says he uses a better grade of CBN. I do have a 1000 grit from Ken. First few sharpenings with it made me think there is a possibility of the really fine grits clogging up with even M2 or the other more fancy metals. No conclusion there. Dave and the Cuttermaster guy from up in Canada also felt that it was possible for any thing over 600, When I retired my 80 and 180 grit from Dave, after 8 or so years, the polish on the bevel was more shiny than the polish left from either the 600 or 1000 grit wheels. I do like these for my skews and some times for shear scrapers, but shear scrapers are still an ongoing experiment, honed VS fresh off the grinder burrs and burnished burrs....

robo hippy

 

[Chuck Barone]

Thanks so much for sharing all your CBN experiences, it's been very helpful. I'm still undecided on grits. Having a secondary bevel makes sense although I have never tried that. I am assuming that bevel is quite short? Chuck