CBN break-in

[Harry Robinette]

Alright I got a CBN wheel from Dave 180 grit but have a question.Been over all the old CBN post I could find and can't find a time limit or number of tools or anything about how long it takes to break-in so it's doing what it's suppose to do.:confused:
Right now brand new it leaves huge gouges on the bevel 10 time that of my 80 grit Norton SG.:eek: I really hope this is just the break-in and it's going to get better like everyone says.:(
I do trust all you guy's and girls here with how great they are but this looks scary on the end of my gouge.:eek:
Is there a way to speed up the break-in time without hurting the wheel ?
As always Thanks for the help.:D

[Roger Chandler]

Harry, I did not worry about a "break -in" period with my 180 grit CBN wheel. That being said, I deliberately took a large Alan Lacer Skew and put a complete new bevel edge and used it to put a new edge on most of my tools. The new bevel on the large and heavy Lacer Skew did take some of the coarse-ness out of the grit, and it still sharpens like new, but feels a little smoother when you run your fingers over it, than it did out of the box.

I get a superb finish on my gouges with a light touch........a heavy pressure will grind away a lot of tool in short order, so light pressure is the order of the day with these............don't know if this helps you or not, but I have given you my experience with my CBN wheel........

I would like to have the 320 grit as well someday!

[Prashun Patel]

Try using a lighter touch. A gouge should only require a light gentle roll to the left then to the right, then done.

[Reed Gray]

Had mine for a while now, and don't really know how long it takes to break in. It does cut a bit coarse at first, which to means take very light cuts/grinds with it, unless you are shaping. I didn't really notice it being rough. Main difference with the broken in wheels is that the surface left is more shiny, but the wheel still takes off a lot of steel.

I don't know of a 320 grit wheel.

robo hippy

[Bob Bergstrom]

It should't take much pressure to achieve the edge. It was one of the things I had to overcome when I started using the CBN. I would say the first 50 grinds will slowly start to become finer and a more uniform edge. You can go right through a 3/8" spindle gouge grinding too hard. Let the tool float on the CBN. I found the edge from the new wheel worked just fine, but it did seem to get even better as time went on. I also have the 80 grit and it really takes metal off in a hurry.

[Harry Robinette]

Thanks to everyone, I really did just barely touch the wheel I thought but I'll be trying it allot more in the future. I had to use a very light touch on the Norton SG also but maybe I need to be lighter even more.

[Steve Schlumpf]

Harry - when I got my CBN wheel at the St. Paul symposium, I was surprised at just how fast it removed steel! I also noticed that the fresh edge of the gouge was very ragged! I was surprised at that as I thought the 180 grit would create a smoother surface than my 150 grit wheel. I think it took a couple of months before I noticed that the wheel itself was smoother to the touch and the grinds on my gouges were very smooth... so it does take a little time/use before it 'breaks in'. Stick with it... it is a great wheel!

[Alan Trout]

Harry,

I bought the 180 grit wheel from Dave a couple of weeks ago. All I can do is echo others comments about a light touch. The first thing I did with mine was sharpen a skew and reshaped some gouges that I wanted different grinds on. The surface of the wheel is much smoother after those tools but I still think the surface of the fresh wheel was better then off of my 100 grit AO wheel and sure does cut much faster. When I get a little more cash I am going to by the 80 grit wheel as well. So far I am very impressed.

Good luck

Alan

[Jeffrey J Smith]

I've been using them for about 8 months now, and can see a difference in the smoothness of the grind from when they were newly installed. That said, I'm not sure I can feel a difference (from new 'til now) when I cut. From the beginning, my finish cuts were cleaner. As mentioned, a light touch is all that's needed, and generally a single, gentle sweep of the edge is all that's needed to refresh an edge. I spend less time at the grinder and get a better edge than I ever did with matrix wheels.

[Dave Mueller]

I have traditionally used a Tormek because of the smooth finish it gives. I recently bought a D-Way 180 grit CBN and have started using it for parting tools and skews. The finish from the CBN is not as fine as the Tormek, but is better than the Norton I was using (don't remember the grit). I have not noticed any difference in the CBN finish as it "wears in". I think light cuts are the key.

[Fred Belknap]

I have to agree with the light cuts. One other thing I do that seems to help is use a diamond cone shape file on the inside after sharpening, I just go over real light.

[Reed Gray]

A friend and mentor of mine has been turning his 'Grimple' trays (small Myrtle bowls) for almost 20 years at about 700 to 800 per year. Larry can give a weather forecast by how the wood cuts because he has his process perfected. He got one of the 180 grit wheels a while back. At first, he didn't really care for the cutting edge it left, but after it broke in, he ordered another wheel, saying it was fine now. My 'theory' is that the burr that is left is responsible. For sure, on my scrapers, the burr left is far better than the one from standard Al.O wheels. Fairly heavy and sturdy, and great for heavy roughing of bowls. After the break in, I don't really notice much difference, but think that on a gouge, the burr might be a bit heavy, and a quick hone on the inside of the flutes might help it out. I never bothered. I did notice long ago, that the burr left on a gouge would hinder high angle shear cuts, but now, I just use scrapers for that, and with the scraper, it is beneficial.

robo hippy

[Harry Robinette]

Thanks all
I used it today to sharpen some of my old Sorby and Crown HSS and then did my Thompsons . I tried to use the middle of the wheel and it is getting smoother so tomorrow I'll do the same to the sides and things will be fine. Again thanks for the help as I always get from everyone here and I well revisit this in a couple months hopefully after a break-in.