CBN wheel grinding dust

Discussion in 'Woodturning Discussion Forum' started by Emiliano Achaval, Nov 6, 2017.

  1. Emiliano Achaval

    Emiliano Achaval

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    I dont know how I missed it before. I have been in my new shop for 2 years. Today the sun was shining right on my 8 inch industrial Baldor grinder. As I'm sharpening, I tought I was seeing regular dust from my turning, i was turning a very dry Lychee piece then. Then I realized in horror that it was metal shavings floating in the air! I stopped grinding and it went away, started grinding and sure enough, very tiny metal pieces floating again. Today I was lucky, I was wearing a mask. How many times I have done it in the last 21 plus years of turning without a mask!!!!! Wow, had no idea metal could float like that, I have earth magnets all around the grinder, loaded with metal dust, but I guess not all goes there.... Needles to say, I will always wear a mask now. I have started wearing one all the time since last year I had 100% sinus blockage that almost needed surgery...
     
  2. hockenbery

    hockenbery AAW Advisor Staff Member

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    I put magnets on the grinder to attract the metal.

    One issue with CBN is they don’t convert the metal ground off to sparks so the metal,flakes have to go some where
     
  3. Emiliano Achaval

    Emiliano Achaval

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    Al, I have several magnets, front and back, maybe they are too loaded with the metal dust and not doing their job, its a pain to clean them. Someone told me how to clean them, maybe it was here, inside a ziplock bag, then just throw the bag away... I think I feel the metal in my lungs, lol. What an eye opener!! No wonder I almost had to have sinus surgery... I bought the mask that Terry Scott uses, the Dust Be Gone is useless, I could see crap coming out of my nose at the end of the day.... I felt I needed to let people know, if the sun doesn't hit the right spot, the particles floating are unseen... Wow.
     
  4. Jamie Straw

    Jamie Straw

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    Be careful with how you mount the magnets. One of our members didn't batten his down well, and the CBN wheel grabbed it and threw it at him! A recent idea, not fulfilled yet, is to put a sheet-metal shroud in back of the grinder, and put magnets on the back of it. Also, I have two barn magnets that came with countersunk holes, to be mounted beneath the wheel. Plastic wrapped over these items will make removing the metal filings pretty easy and not too messy if done over the trash can.
     
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  5. Emiliano Achaval

    Emiliano Achaval

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    Wow!! Thanks for sharing that!! Never imagined that scenario!! I usually have my face mask up when I'm sharpening... Stupid question: would the sheet metal become magnetized? That, my friend is a great idea if the whole sheet metal would attract the micro particles... Tomorrow I will clean my magnets, and I'm also ordering some bigger ones... Thanks for posting. Aloha.
     
  6. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I'm even happier about using a Tormek as we become increasingly aware of health risks associated with breathing dust because the water bath and low speed eliminates that problem. I've examined the stuff that collects in the water tray since I started using a CBN wheel and a small part of it is boron nitride in addition to the steel. Depending on the type of tool steel, the super-fine dust could include elemental cobalt, chromium, manganese, molybdenum, vanadium, and other potentially toxic metals as well as a bit of boron nitride. Any dust that gets in your lungs is bad because it's there for the duration.
     
  7. Gary Beasley

    Gary Beasley

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    Sounds like dust collection on cbn grinders are the next big thing. DC on regular grinders is problematic as the sparks always have the potential for igniting wood dust. Might have to be a separate system for them either way to ensure safety and effectiveness. I like the low speed water sharpening systems for that point as well.
     
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  8. Mark Wollschlager

    Mark Wollschlager

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    Rare earth magnets salvaged from old hard drives in double plastic bags stuck around the wheel.
    Dust mask.
    Dust collection at the grinder is a potential problem as some sparking and/or hot debris has caused fires inside the collector or hoses.
     
  9. John Torchick

    John Torchick

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    Emiliano, my father always said the only stupid question is the one not asked.
     
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  10. robo hippy

    robo hippy

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    This is a problem that I started to ponder when I opened up a box for one of the Moffat lamps with the magnetic base. It was in one of the dog eared type boxes with the flaps you tuck into slots, and up about 30 inches above my grinder. It had metal dust on the magnet, inside the box. So much for the theory that metal dust is heavier than wood dust and it will fall out of the air. Another turner hung a magnet up 10 feet away from his grinder and it accumulated metal dust... So, how to deal with it... I cringe every time I see a grinder set up with CBN wheels and no wheel cover. Yes, the wheel will never blow up, but the cover helps to contain the dust. I figure the magnet type set up will pull out maybe as much as 80 to 90% of the metal dust. You can not hook up your standard dust collector to the grinders because of spark problems. There are specialized dust collectors for grinders that are fire proof, but I never looked into one because they would be very expensive. One of the 'round-2-it' projects I have is to make a hood for my grinders, similar to my sanding hood for bowls, and hook up one of the air scrubbers to it. There can't be a direct feet to the scrubber, but with enough air flow, and an open space so all metal sparks will die, it should get 99.9% of the dust. I do put some lapping fluid on my tool bevels before I sharpen, most of the time anyway. This would kind of make for a wet wheel situation where you get most of it before it gets into the air. Still needs some work. Shop Vac does make an air scrubber that is a tube shape rather than the bigger boxes like Jet and others.

    Only other problem I have with the metal dust is on my tools and hands when I am turning wet wood. I hate the black freckles... I have taken to wiping off both my hands and tools with the wet shavings before doing finish cuts.

    robo hippy
     
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  11. Bill Boehme

    Bill Boehme Administrator Staff Member

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    It was a new experience for me when I put the CBN wheel on my Tormek and ran it dry as Ken recommended and saw the metal particles stuck to the tool edge and on my hands. I decided to heck with running the wheel dry. I'm running it in water now and no more mess.
     
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  12. Tom Gall

    Tom Gall

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    Try installing an inexpensive box fan (20") behind your grinder to pull the dust away. I installed a 3-sided aluminum channel to hold a piece of filter paper (purchased a roll about 25 yrs. ago) and installed a regular furnace filter over that. You can probably just use the furnace filter (a good quality one) without the filter paper if you can't find a source. This works amazingly well.
     
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  13. Ron Borowicz

    Ron Borowicz

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    Bill,
    I am about to purchase a CBN wheel for my Tormek. How long have you been running it with water? Do you use distilled water? Any adverse affect on the CBN wheel? Thanks.
     
  14. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I'm not going to say it's OK to hook a shop vac or DC to a grinder, but it's just my personal opinion that it's not a problem with some caveats:
    • You are doing light edge touch up and not heavy shaping
    • You are using ceramic, aluminum oxide, or CBN wheels that have little or no sparking
    • There is a large volume of airflow
    • The ducts or hoses don't have a lot of wood dust built up
    It's just my opinion that the sparks have sufficiently cooled by the time they have traveled a couple feet. Just because I haven't burned my shop down isn't proof of anything.

    A fellow club member told me of an incident where he started a fire in his Powermatic belt sander when sparks from sharpening turning tools set fire to the wood dust. If my memory is correct, it had a built in dust collector in the base. He said it took him awhile to realize that the smoke smell was coming from the belt sander. I believe he said that he rolled it out the door and hosed it down. Last time I saw the sander it was still running fine, but I think that he might have stopped sharpening his tools on it.
     
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  15. robo hippy

    robo hippy

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    The metal dust can ignite as well if the fines build up and you get sparks in it. This has happened with the fine steel wool before, but I don't know all the specifics.

    robo hippy
     
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  16. Jamie Straw

    Jamie Straw

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    Ah, my friend, it's unlikely that your shield would stop a bar magnet flung off of that CBN wheel. Ouch. I dunno about the sheet metal becoming magnetized, it might. One of my M42 NRSs got totally magnetized from laying against a little magnet-tray in the tool cart I use at BARN. Here's the Amazon link to the bar magnet I bought for under the wheel, note the countersunk holes. Just plan to use little circle magnets on the back of the sheet metal.
    [​IMG]
     
  17. Emiliano Achaval

    Emiliano Achaval

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    I have heard of magnets getting picked up by the cbn wheel and thrown back at the turner! Its a tricky issue, not an easy solution... For now, I'm wearing a mask!
     
  18. Emiliano Achaval

    Emiliano Achaval

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    Feel a little better, thanks!
     
  19. Emiliano Achaval

    Emiliano Achaval

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    Thanks Jamie!
     
  20. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I bought it in August at SWAT. I haven't used it a lot because I'm recuperating from back surgery, but I have sharpened most of my turning tools plus knives and whatever else I could find that needed sharpening. I don't leave the wheel sitting in water overnight. I empty the tray and even remove the wheel and dry it with a towel although I'm sure that is going overboard. Except for the first couple tools that were dry sharpened, I've been running it in water.

    Tap water should be fine unless you have very hard water.

    Initially the wheel felt too rough to be 1000 grit, but I think that is because the CBN is applied extra thick. So, for the first several uses the water had a lot of sparkle as some of the excess CBN sloughed off. Now, it feels much smoother and the bevels are close to the gray wheel results, but still not quite as refined.

    There was one design faux pas that I discovered ... the Tormek stone is flat on the inboard side and the outboard side is recessed about 3/16". The CBN wheel is recessed 3/16" on both sides. This means that the CBN wheel is closer to the frame of the machine ... touching, in fact. Luckily, I had an extra spacer/washer of the right thickness from the old axle. With these two thick spacer/washers, the CBN wheel sits the perfect distance from the frame so that I am able to install the water tray.
     

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