Blown away by CBN

[brian zawatsky]

Received my CBN wheels from Ken at Wood Turners Wonders today after what felt like forever (but was only actually 4 days lol) and I am totally blown away.

I was at the point where I was seriously considering dropping a considerable chunk of money on a big old pedestal grinder and a VFD just to try and get a smooth running variable speed grinder. I have a 3 year old 8" Delta variable speed unit that I bought at Lowes.

No matter what I did, I could not get the Norton white wheels that I was running to spin true. The vibration drove me absolutely bonkers and made it very difficult to get a smooth chatter-free grind on a bowl gouge.

So I ordered a pair of CBN wheels from Ken, a 180 & 350. Holy crap what a difference!! It's like I got a brand new grinder AND 2 sweet wheels for 250 bucks. The 350 grit wheel puts such a sharp edge on that Thompson steel I can almost get a finish-ready smooth surface right off the tool! It's unreal. And the 180 is perfect for raising a nice burr on scrapers. The aluminum wheels have a pretty distinct "ring" to them as you grind. I kinda like it lol

I should have bought these things months ago. Now I need to replace the old school carbon steel spindle gouges I learned on with some good high quality Thompson gouges. This is an expensive hobby.

[Roger Chandler]

Yep, that CBN makes for a super sharpening setup. My 80 & 180 grit wheels are steel and they do a fine job. Congrats on your upgrade....the smile on your face won't go away for a while! ;)

[Ralph Lindberg]

Yup
Several years ago, right after D-Way introduced CBN wheels to the wood-turning community, my wife and I were taking an all-day class. The sharpening station had been lent by one of the clubs turners who had just gotten a set of these from D-Way (Dave is a member of the local club).
Well, at one point the DW walks over to sharpen one of her chisels, walks back and informs me that as soon as we can afford it we are getting a CBN wheel
She got one for her birthday :D (along with some other stuff)

[John K Jordan]

I should have bought these things months ago. Now I need to replace the old school carbon steel spindle gouges I learned on with some good high quality Thompson gouges. This is an expensive hobby.

Welcome to the club! I resisted for years 'cause I'm a cheapskate even though some friends were raving about them. Once I got the first one I felt like you, I should have bought it a long time ago. Fortunately the price has dropped. I currently use 4 wheels, one 10" on a Tormek. I do prefer the slower speed of the Tormek. I would love to have a variable speed grinder and slow it way down. OTOH, 80 grit on a bench grinder is amazing.

With a shop full of Thompson tools you'll be unstoppable. The Thompson and Hunter tools are the ones I use the most.

A suggestion: consider the fine steel dust floating around the room. I found super magnets coated with the black dust, and the magnets were more that 10' away on, high on the back side of my bandsaw. I put a magnet behind one wheel and I plan to try a switchable magnet.

JKJ

[Adam Petersen]

I could not agree more. I have the same grinder and had two white wheels on it. Even with the upgraded hubs from Woodturners Catalog and some carefully placed stickers, I still had too much vibration. I bought a 180 CBN from WTW and will NEVER look back. I kept a white wheel on for my small, homemade hollowing tools. I don't trust the steel on the CBN. I hope to someday pick up a cheap 8" grinder as a second one for my white wheels so I can get a different CBN grit like you have. 180 works well for me now though. Congrats!

[John K Jordan]

[QUOTE=Adam Petersen;2636152... I kept a white wheel on for my small, homemade hollowing tools. ...[/QUOTE]

Hey, have you tried the Oneway balancers for grinders? Before I got the CBN wheels I used them for years for super-smooth AlOx wheels.

JKJ

[Ralph Lindberg]

..
A suggestion: consider the fine steel dust floating around the room. I found super magnets coated with the black dust, and the magnets were more that 10' away on, high on the back side of my bandsaw. I put a magnet behind one wheel and I plan to try a switchable magnet.

JKJ

John makes an excellent point

Metal dust control is as, or more, important then wood dust control.

Some of the elements in our "new" tool steels are, well, not healthy. I've got some notes on this...


Manganese
Is a neurotoxin. In larger amounts, and apparently with far greater effectiveness through inhalation, it can cause poisoning in mammals with neurological damage that is sometimes irreversible.

Tungsten
Tungsten interferes with molybdenum (https://en.wikipedia.org/wiki/Molybdenum) and copper (https://en.wikipedia.org/wiki/Copper) metabolism and is somewhat toxic to animal life

Vanadium
Vanadium is LIKELY SAFE in adults, if less than 1.8 mg per day is taken
Required in low doses for bone growth.

Molybdenum
High levels of molybdenum can interfere with the body's uptake of copper, producing copper deficiency. Molybdenum prevents plasma proteins from binding to copper, and it also increases the amount of copper that is excreted in urine.

Chromium:
Trivalent chromium (Cr(III)) ion is an essential nutrient in trace amounts in humans for insulin, sugar and lipid metabolism, although the issue is debated.
While chromium metal and Cr(III) ions are not considered toxic, hexavalent chromium (Cr(VI)) is toxic and carcinogenic.

[John K Jordan]

Metal dust control is as, or more, important then wood dust control....

Since a magnet will pick up a great deal of steel dust and it can be hard to clean off the magnet, some people mention putting the magnets in a plastic bag then pulling it away to release the dust. This works unless you have a lot of dust and a bag that's not too strong.

As an experiment I ordered one of these to mount behind the wheel. Rotating the switch releases the force so I'm hoping it will pick up enough dust and be easy to clean. I'd like to fit it right under the tool rest if I can. I'll report back after a test.

349832

JKJ

[brian zawatsky]

That's a good idea John. I did take notice of the fine steel dust that accumulated around the grinder just from touch up sharpening while turning a large bowl.

[Bill Boehme]

?.. As an experiment I ordered one of these to mount behind the wheel. Rotating the switch releases the force so I'm hoping it will pick up enough dust and be easy to clean. I'd like to fit it right under the tool rest if I can. I'll report back after a test....

The "switch" is just a cam to separate the magnet loose from the surface where it is attached. It's a nice shop accessory, but if I understand what you are wanting to evaluate, i don't think that this is what you are looking for.

[Sam Beagle]

Oddly enough I just picked up the 180-350 combo from woodturning wonders. I am ecstatic about the wheels, the balance and cut is unreal. I DO HAVE A QUESTION THOUGH
So I have a pile of the big yellow/orange Handled sorby tools from the 80s. So can I sharpen them on these CBN wheels. Sam

[brian zawatsky]

Sam, from what I understand you're not supposed to sharpen anything softer than HSS on a CBN wheel or the wheel will load up, so high carbon steel is out. If the tools are HSS, then you're good. I don't have any Sorby tools so I couldnt say

[Brice Rogers]

I think that it is okay to grind either HSS or high carbon steel. They are both much harder than soft steel. If a file "skitters" off the surface, it is hard enough. If it digs in, don't use a CBN

[John K Jordan]

Sam, from what I understand you're not supposed to sharpen anything softer than HSS on a CBN wheel or the wheel will load up, so high carbon steel is out. If the tools are HSS, then you're good. I don't have any Sorby tools so I couldnt say

Brian,

Reed Grey has done a lot of experimentation on grinding things with CBN. Did you see his article? http://www.robohippy.net/featured-article/

He says high carbon steel was fine. He even ground mild steel and aluminum and while they did load up the wheels there was no damage - he "cleaned" the wheels by grinding a HSS scraper.

I've ground high carbon non-HSS and even a small amount of non-hardened steel, bolts, and more with no detectable problem. I would not hesitate to grind a hardened hollowing tool bit. You might send Reed a note and see if he has refined his findings since he wrote that.

JKJ

[Ralph Lindberg]

Which is the same thing that Dave (D-Way) says. HSS and HCS (hard) are OK.

Mild steel, brass, etc load the wheel up

[Reed Gray]

Steel like bench chisels is fine. So is an axe head and most digging shovels as that steel has been hardened. Lawn mower blades are too soft.

Loading up the wheels is not a good idea. Yes, it can be done, yes, you can get most of the loading off by using a heavy scraper especially if you wipe on a bit of the Trend lapping fluid, but still I would avoid it.

For experiments to be done next year, I have a micro camera that blows up 80 grit particles to BB size. We are going to load up a wheel with every thing and then clean it off, getting before and after pictures.

As for the metal dust, I am wondering about 'wet' grinding as a habit. Cindy Drozda had a set up with the old Woodcraft diamond grinding wheel where she had one of the cheap 1 inch wide paint brushes that she kept wet. That might keep the dust down. If we are to get serious about keeping that fine dust out of the air, we need a dust collector and hood for the CBN wheels. The magnets will get some, but not all.

I don't ever remember any discussion about metal dust with the old white, blue, or pink wheels. There was some discussion about the dust from the wheels when you trued them up.

I never tried the Oneway balancing system. I found I could true up the wheel with a dressing stick and a platform, truing up the face, and the sides of the wheel (VERY GENTLE side pressure or the wheels can shatter!!!). That did a good enough job for a good quality wheel. The wheels that came standard on my Rikon 1 hp grinder, well lets just say I wouldn't give them to some one I didn't like...

robo hippy

[brian zawatsky]

Thanks Reed. Good to know I won't need a whole different grinder setup for my bench chisels and such.

[David M Peters]

I have an 80/220 WTW CBN setup and have done shaping/sharpening on old screwdrivers and lawnmower blades with no loading issues. I'm really happy with them.