Metal Dust Control

[Greg McClurg]

This topic may have been discussed previously, but I didn't find anything doing some searching. I'm wondering what turners are doing, if anything, in capturing the metal dust that is created when sharpening your tools? I use CBN wheels and have a magnet underneath the wheel, but there is obviously a lot of metal dust that is not captured. Any suggestions?

Thanks,
Greg

 

[RichColvin]

Greg,

This is one of the very strong reasons to invest in a Tormek.

Rich

 

[robo hippy]

There are no 'hobby' level metal dust extractors available. I have been pondering this for years now. Best bet I can think of would be one of the air scrubbers, and a hood over the grinder. I would have the filter back a bit from the grinder, just to eliminate chance of a spark settling down and then the wind fanning it into a flame. The metal dust does float around in the air like wood dust does. One turner hung a magnet 10 feet away from his grinder and it got dust into it. I had a magnetic base light, in a box, maybe 3 feet above and off to the side from my grinder. I opened it up and there was metal dust on the inside. Wish there were better options. I cringe every time I see a CBN wheel being operated with no guard around it at all. It wouldn't take a lot of air flow to pull the dust out of the air. At least not as much as the shop dust collection system would pull....

robo hippy

 

[Jim Reynolds]

In the lathe classroom at Marc Adams School of Woodworking the grinders (with abrasive grinding wheels) are hooked up to ash vacuums. The on switch turns both (grinder and vacuum) on. The vacuum continues to run for for 30ish seconds after the power to the grinder is turned off. This isn’t a perfect solution because you can see black powder residue in front of the grinder at the end of the day.

 

[Michael Brown]

I wonder if a 600lb mag-loc on a 3 x 5 pig iron plate would be effective enough if it was set immediately under the CBN, just above the wolverine (assuming everyone everywhere has the same setup as I do). I wear mechanic nitrile gloves while sharpening, and my trusty breathing PPE... After the first few times tasting metallic using CBN, and not being able to scrub the charcoal color off the back of my hands...

 

[hughie]

Magnets are probably the best option, as any alternative won't be cheap. Other than perhaps to fit a suction line to the rear of the grinder guard, it will be effective but not 100% for that you would need volume and velocity to capture all. Is it available? Most certainly but at a cost as it will be a commercial or industrial piece of gear.

 

[John Whitley]

For what it’s worth, I took a swing at this in my new shop space. I scored a refurb deal on a JET JDCS-505, a metal dust collector stand for bench grinders. The grinder is a Baldor 8” with cast iron guards and rear extraction ports. Jury’s still out as to whether this is a viable approach, and under what circumstances. I’m hoping that it’ll be good to maintain air quality for sharpening while turning. I’ll be surprised if it’s adequate for heavy grinding operations, e.g. major tool reshaping, grinding a custom tool from an HSS blank, etc. The collector definitely helps significantly with metal dust, but I’ve only just gotten measurement capability setup today (via a Dylos D1100) and have been preoccupied getting used to it and sorting out baselines. In the meantime, it’s the trusty P100 half mask until I know I’m getting adequate collection.

I haven’t employed any magnets yet, as I want to understand how well the dust collector works on its own. As I dial things in, it may be possible to use magnets to augment the collector’s effectiveness, ala magnetic dust guides.

(and this from just a few hours ago: yes, you can squeeze a 1.5” wide CBN wheel into the 8” Baldor‘s guards with some arbor spacers.)

 

[Greg McClurg]

Great idea about using an ash vacuum. I actually happen to have one that has never been used so I'll give this a try.
Thanks for all the ideas and comments.

 

[Dean Center]

Years ago, and at least one shop ago, John Lucas showed photos of his DIY vacuum set up on his grinder. You might be able to search back and find it, as it probably has a couple of good tips.

 

[robo hippy]

John, I have 2 Baldor grinders. I did have 5/8 long spacers made by a machine shop, that I cut a groove in so they would slip over the axle pin, and it also spaced them far enough out so that I could tighten the nut against the wheel. I tried to stack washers from the big box store, but they were pretty low quality and made for a lot of wobble.

No clue as to what an 'ash' vacuum is, going to have to look that one up. As for magnets, I look at them like I look at the big gulp type vents/hoods for dust collection when sanding bowls. They do an okay job, but dust mask is still required. My sanding hood that I use when sanding bowls captures all of the dust, other than what gets on my hands. Tested it out by sanding black walnut for 6 hours, and nothing up my nose or on my glasses, and I could not smell the black walnut at all. Best guess for me would be a filter system of some sort, and that filter would have to be fire proof. I did mention to Oneida once about this situation, and they commented that it sounded like a good idea. Haven't heard anything else since then....

robo hippy

 

[John Whitley]

[...] I did have 5/8 long spacers made by a machine shop, that I cut a groove in so they would slip over the axle pin, and it also spaced them far enough out so that I could tighten the nut against the wheel.

Thanks Reed. I should have mentioned: After a fair bit of hunting around, I found a set of reasonably priced keyed arbor spacers(**). Precision Brand Arbor Spacers, 19 pack. These fit my 8" Baldor's arbor perfectly. Of course, they're out of stock as I type this, but I ordered mine recently.

IIRC, I ended up stacking spacers from that set to around 0.30" or so, sufficient to get the wheel roughly centered in the guard. I used WoodTurners Wonders' self-aligning spherical washer on the nut side, which provided thread clearance for the nut to be fully seated.

(**) For anyone unfamiliar, arbor spacers are machined for exactly this kind of purpose: controlling spacing on a motor arbor. As Reed notes, random washers won't be remotely flat, making for wobble problems.

 

[Gerald Lawrence]

Of note : place the magnet in a zip lock bag so the dust can be cleaned off. On a bare magnet will never come off. Just in case there are some new folks reading this.

 

[robo hippy]

John, I haven't heard of those. I would suppose you could get some soft steel, drill a hole for the arbor shaft, and then using turning tools true up the faces of the spacer. M2 HSS will take care of average steel with no problems.

robo hippy

 

[Mark Jundanian]

@Greg McClurg , here is one thread I found on the subject.

CBN wheels: no dust but a lot of metal particles

Hello, I recently mounted a eight inch 80 grit CBN wheel on my seven inch Baldor. Of course I had to remove the protective screen and guards. The result is not so satisfactory. It is true that it grinds true and faster and without dust, but the metal particles are everywhere. I now have to use...

www.aawforum.org

I still use, and am happy with, the vacuum setup that was described in AWT magazine.




It collects most, but not all, of the dust. And I think is more effective than magnets, though you could try a combination.

 

[Tom Lucas]

There was a recent tip/article in AWT or FWW magazine (can't remember which) where a reader built guards out of 5 gallon buckets and lined them with sheet magnets. I currently use 2" strong magnets sitting under the wheels.. They do an OK job but definitely miss dust that flies off the top of the wheel before reaching the magnets below. I was thinking about giving the sheet magnet collector a try. This likely could be adapted to also use a vacuum. I just worry about a fire in the vacuum if using a stadard shop vac.

 

[John Whitley]

In case anyone reading this thread isn’t familiar, it’s worth perusing Bill Pentz’ dust collection site. It’s … voluminous … but relevant to this thread are Pentz’ discussions of specific challenges of dealing with fine dust collection at the tool. Especially, the “jet” of material right at the point of cutting (for us here, grinding). Another thing Pentz gets into is the difference between a dust collector (high CFM, low static pressure) and a vacuum (low CFM, high static pressure) and how that affects fine dust collection. His site is focused on wood dust, but a lot of the conceptual and practical details apply to metal as well.

Whatever approach, I think a really critical (and challenging) part is to actually measure results. There’s a big difference between a system that just “keeps the shop tidy” vs one that rigorously captures hazardous dust we can’t even see.

 

[John Whitley]

There was a recent tip/article in AWT or FWW magazine (can't remember which) where a reader built guards out of 5 gallon buckets and lined them with sheet magnets. I currently use 2" strong magnets sitting under the wheels.. They do an OK job but definitely miss dust that flies off the top of the wheel before reaching the magnets below. I was thinking about giving the sheet magnet collector a try. This likely could be adapted to also use a vacuum. I just worry about a fire in the vacuum if using a stadard shop vac.

I definitely think this is a path worth exploring. Traditional grinder guards mostly seem to be designed to reduce damage from an exploding grinding wheel, with dust collection as an afterthought. Wheel bombs aren’t so much a concern with the increasingly popular CBN wheels, so it’s interesting to think about shifting the design to maximizing dust control. (and c’mon, magnets are cool. ;-)

 

[Tom Lucas]

I definitely think this is a path worth exploring. Traditional grinder guards mostly seem to be designed to reduce damage from an exploding grinding wheel, with dust collection as an afterthought. Wheel bombs aren’t so much a concern with the increasingly popular CBN wheels, so it’s interesting to think about shifting the design to maximizing dust control. (and c’mon, magnets are cool. ;-)

I went out and made one today. Turned out pretty good. Just sits behind the motor, self centers, and will not move into the wheels. No tools or fasteners needed to install/remove. Will hold a 3" strip of magnet. I'm waiting on the magnetic strips, which I just ordered from Mcmaster-Carr. I didn't trust the magnetic strengths of those on Amazon. Cost me, but hopefully they'll be good quality and will collect the dust. Will post back with photos when magnets in place.

Question for those who might know: Other makers said they covered the magnets with packing tape to "make it easier" to remove the dust. How is this so? Isn't it pretty simple to just vacuum the thing out? Or rake it off with a finger? How does the tape make that easier?

 

[Gerald Lawrence]

I went out and made one today. Turned out pretty good. Just sits behind the motor, self centers, and will not move into the wheels. No tools or fasteners needed to install/remove. Will hold a 3" strip of magnet. I'm waiting on the magnetic strips, which I just ordered from Mcmaster-Carr. I didn't trust the magnetic strengths of those on Amazon. Cost me, but hopefully they'll be good quality and will collect the dust. Will post back with photos when magnets in place.

Question for those who might know: Other makers said they covered the magnets with packing tape to "make it easier" to remove the dust. How is this so? Isn't it pretty simple to just vacuum the thing out? Or rake it off with a finger? How does the tape make that easier?

Tape would reduce the cling but also might reduce the attraction. I do not think a vacum will clear the particles. I use a zip lock bag and sometimes is hard to clear it.

 

[Tom Lucas]

Tape would reduce the cling but also might reduce the attraction. I do not think a vacum will clear the particles. I use a zip lock bag and sometimes is hard to clear it.

Gerald,
Up to this point I had been using some very strong 2" round magnets inside plastic baggies. Turning the bag inside out to remove worked well.....until sparks melted the baggie so I had to tear it to get the magnets out. Still worked OK but some of the dust did get on the magnets. My vacuum with a brush tip got those off pretty easily. Note that these 2" magnets would pinch/smash a finger if in the way when they pull to another metal surface - very strong, designed to hold antenna radomes on the hood of a car at highway speeds. Brush on the vacuum seemed to be the trick.

 

[robo hippy]

Those Mag Switches (brand name, you can get some direct, and/or Woodcraft carries them) might work for metal dust collection. Turn the knob one way and it is magnetic, turn the other way and magnet turns off. I am not a fan of no wheel guards on the CBN wheel grinder set up. Anything to help control the metal dust is essential for lung safety.

robo hippy

 

[Tom Lucas]

My finished magnetic collector guards. Haven't tried them yet, but ready to go.

 

[Tom Lucas]

Two more photos.

 

[Vincent Vogel]

Tom, looks like a good idea. let us know how it works

 

[Ken Dambrosio]

This topic may have been discussed previously, but I didn't find anything doing some searching. I'm wondering what turners are doing, if anything, in capturing the metal dust that is created when sharpening your tools? I use CBN wheels and have a magnet underneath the wheel, but there is obviously a lot of metal dust that is not captured. Any suggestions?

Thanks,
Greg

Stop I purchased online earth magnets that were extremely strong. I placed them in the front and back of my grinder where they collected an enormous amount of filings

 

[Bob Raasch]

Of note : place the magnet in a zip lock bag so the dust can be cleaned off. On a bare magnet will never come off. Just in case there are some new folks reading this.

Great idea, yes metal shavings are almost impossible to remove from bare mag.

 

[Ken Dambrosio]

Thank you for this simple solution to the difficult job of removing the metal filings from the earth magnets.