Thread: Power Sharpening Options

I just picked up a second tormek bench grinder mount for the slow speed grinder so now switching between the T8, or either cbn wheel is all on the same bench and trivial compared to previous setups I’ve had

Originally Posted by D.W.

I made the comment about dust just from noticing it in the air. however, I've never seen it to be an issue and would not want to try to come up with a drip or lube system on a dry grinder to deal with it - a vacuum hose sitting on top of the grinder would pull in anything significant.

Admittedly, I've never used a particle counter near the grinder for maintenance sharpening, but doubt you'll find anything significant doing that - it's dust backlit somehow that is evident.

Because most of the tools I work with contain Cobalt, Chromium and Vanadium I'm cautious about breathing in the fine metal dust when grinding those tools.

I always run a particle counter in my woodturning workshop to detect the levels of fine wood dust in the air and that counter can also detect any suspended fine metal dust particles. Without any dust capture I get very high levels of suspended fine dust coming of the CBN wheel for up to a minute with some residual metal dust detectable up to 3mins...

Those levels are too high for me without some form of dust extraction.

I use magnets where the tool contains sufficient magnetic iron for the fine particles to get captured and that improves things a bit.

Magnet metal dust collector after 6 mths.jpg

I also use hoods with a vacuum attached where there there is little to no magnetic iron content, as is the case with tungsten and tantung.

Like most things I do, I start with a prototype to test out the concept/design and more often than not if the rough prototype doesn't fall apart I keep using it. Despite their crudeness, my particles counter indicates that all of these are highly efficient...

Dusthood prototype 3.jpg Dusthood prototype 2.jpg Dusthood prototype 1.jpg

Metal dust reading with use of dusthood extractors.jpg

how close is the particle counter to the dust source?

I put the same particle counter in my shop when grinding chisels, and I see high numbers for longer and have decided that it's time to put point capture under the contact wheels instead of fretting that it might get in the way.

By longer, I mean the numbers will be up for hours - from 500 dropping quickly at first but perhaps still being 75 hours later. I'm only grinding simpler steels most of the time, but the amount of particles were so high that I noticed when I took my mask off I could smell steel even in other rooms.

And last week, I realized why. If I'm wearing fleece or something in the shop, it's almost like the fleece becomes active with dust particles - if I walk around with the particle counter near me or behind me, the counts jump.

Point collection has reduced that by a factor of ten, and the counts in the shop are more like 50 10 feet from the grinding wheel.

thanks for putting numbers to the CBN - I could see the dust volume in raking light and just never measured it.

Originally Posted by D.W.

how close is the particle counter to the dust source?

D.W.

Apologies for my slow reply, I have been consumed by other matters this week.

The counter sits about 6ft away from the grinder and positioned just a bit above head height where I can see it when I'm working on the woodturning lathe. Primarily used for measuring fine wood dust levels and in particular for when I'm power sanding. The fine dust from that, which is a serious risk for respiratory health, can remain suspended in the air for many hours if not efficiently extracted.

With the tools I'm grinding the risk is more from their toxic metal content, which I also want to avoid. With some of those I'm dry grinding up to #1,000 and that produces very fine metal particles that remain airborne for longer. Until I implemented some control measures I was getting quite high numbers like you.

Hi

I made up some DIY grinder rests with parts purchased from Maker Store in Melbourne. You can obtain,

• 12mm X 1000mm precision rod for $23.00.
• Linear rail shaft supports for $2.60 each.

I had some T slot aluminium that allows adjustment of the 12mm rod

Knife Grinders was run by a very dedicated and respectable individual who sadly passed "before his time".

Originally Posted by Old Croc

Best of luck with them. I got an email from them in response to my query saying they will get back to me, but they never did so I am looking for an alternative wheel from the US.
Rgds,
Crocy.

Originally Posted by NeilS

D.W.

Apologies for my slow reply, I have been consumed by other matters this week.

The counter sits about 6ft away from the grinder and positioned just a bit above head height where I can see it when I'm working on the woodturning lathe. Primarily used for measuring fine wood dust levels and in particular for when I'm power sanding. The fine dust from that, which is a serious risk for respiratory health, can remain suspended in the air for many hours if not efficiently extracted.

With the tools I'm grinding the risk is more from their toxic metal content, which I also want to avoid. With some of those I'm dry grinding up to #1,000 and that produces very fine metal particles that remain airborne for longer. Until I implemented some control measures I was getting quite high numbers like you.

I've seen varying reports on how dangerous the carbides are, vs. some of the elemental items, but I just personally don't want to take too much risk. Since I'm doing a lot of heavy grinding, the combustion part comes in there, too. It's just better to have less dust and not stir it up in my view.

I'm a little more tolerant of wood dust (I don't like it, but not as concerned about it as some are - but it's also the case that I'm not getting daily exposure to wood dust), but I realized after having dark snot off and on at some point, i may need an MRI in the distant future and at this point, even with just "some" metal dust in my lungs, not nearly the amount that someone in industry would have, I have no clue if it's a risk under strong magnetism.

More and more I read about the risks not just from dust, but from liquid mists. Liquid mineral oil for example is a killer even though you can eat the mineral oil and it's relatively harmless (talking about USP type - even the USP bottles warn about mists). It's getting me to rethink everything, just like seeing the particle count go sky high in my daughter's room when she used "shower in a can" or some kind of product advertised to be used mid-day to freshen your hair. I've noticed lots of reports of machinists who never really were exposed to dust, but worked near a liquid coolant environment that would suspend mist and the result is the same for them. Early death in some cases with COPD.

These little particle counters are a real blessing.

I was going to make a little joke of this count, but forgot. My tempering oven is a toaster oven. If you're in the shop, it does a better job with yesterday's pizza due to the proximity of the radiant heat. I heated three pieces and noticed a ribbon of smoke coming out of the toaster oven, smelled like pizza, and made the shop a little hazy looking under the bright lights.

https://ofhandmaking.files.wordpress...6895331350.jpg

240 - from reheating pizza (!!), and it was a little higher before that as you can see by the AQI indicator.

This thread and watching something else caused me to make a simple bowl that sits on a camera tripod - no cost, of junk I had around the shop, and the dust burden is a tenth, and the room next door shows the benefit from it.

And since i rarely sand anything, the fein vacuum that I bought years ago is finally getting use on a regular basis. One needs two vacs if grinding heavily like ceramic - the stuff that comes off of ceramic belts is like burning steel wool. it's harmless in the vac as long as there's not wood dust in it. if there's wood dust in the same vac, even with a long run of hose, you'll soon smell a campfire smell.

(it may be that some of the carbides make for relatively inert particles, but that's academic - what happens when they're ground and they burn a little and so on - not worth the risk to me, and I'm a "safety 7th" kind of person most of the time).

Originally Posted by D.W.

I've seen varying reports on how dangerous the carbides are, vs. some of the elemental items, but I just personally don't want to take too much risk. Since I'm doing a lot of heavy grinding, the combustion part comes in there, too. It's just better to have less dust and not stir it up in my view.

[snip]

(it may be that some of the carbides make for relatively inert particles, but that's academic - what happens when they're ground and they burn a little and so on - not worth the risk to me, and I'm a "safety 7th" kind of person most of the time).

I'm inclined the same way, David. Why gamble with your health when some simple mitigation measures load the dice in your favour.

For what it is worth, while acknowledging that I (and probably most others on this forum) don't have the necessary expertise to be confident about the level of risk we are exposing ourselves to, I posted the following a little while ago on what I found when looking into my risks from grinding turning tools with heavy metal compositions...

I understand that there are three risks from breathing in [the] fine metal dust [from grinding our woodturning tools]. The first is the metal that accumulates deep in the lungs with repeated exposures. It is an identified occupational health risk called hard metal lung disease (HMLD fibrosis). Once it is there it's there for your duration!

https://www.safeworkaustralia.gov.au/occupational-lung-diseases

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6310083/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5102237/

The second concern for me are some of the alloy additives to High Speed Steels: these include cobalt, chromium, tungsten, manganese, molybdenum and vanadium. Some of these additives in some of their forms are known carcinogens.

The third concern is that these elements can find their way via our lungs and digestive systems into our bloodstream and organs and are toxic to us.

For example, here is a list of the key risks in relation to Chromium (VI) from the CDC. Grinding HSS that contains Chromium is known to release Hexavalent Chromium.

https://www.atsdr.cdc.gov/csem/chromium/physiologic_effects_of_chromium_exposure.html#key_points

Effects of Cobalt on the human body.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4637398/

Tungsten

https://www.karger.com/Article/Pdf/29500

Similar concerns have been shown for Vanadium.

There is also evidence that some of these interact in the human body and are more damaging in combination.

For the purposes of this thread the above references are indicative of the risks and are well beyond my (and probably our collective) expertise to analyse in any detail. But, like the known risks for asbestos and silica, I just accept the advice and try to avoid exposure to them.

The exact exposure threshold levels required to cause metal dust health risks will vary from person to person. There are published maximum exposure levels but few of us have the means to measure for those, so I'm inclined to not gamble on being the one who will avoid the risks at even the lowest levels of exposure.

D.W. , NeilS and others reading this thread

And please don't forget a person's exposure to silica dust that most grinding wheels give off as the wheel itself wears down.

Silicosis is not a pleasant disease.

Originally Posted by ian

D.W. , NeilS and others reading this thread

And please don't forget a person's exposure to silica dust that most grinding wheels give off as the wheel itself wears down.

Silicosis is not a pleasant disease.

I'm very mindful of that too, Ian.

Early on in my career I worked in ceramics where silica was in everything we used... from clay and glazes to kilns. So, became very aware back then of the risk of silicosis.

When Aluminium Oxide grinding wheels became readily available I moved away from SiC wheels as soon as I could.

When resin matrix diamond wheels became readily available I moved away from AlOx wheels as soon as I could because the resin matrix diamond wheels shed less abrasives.

When sintered CBN wheels became readily available I adopted those for number of reasons, including there being even less abrasive shed from those.

Slow speed wet grinding greatly reduces the risk from silica based abrasives, but they are too slow at getting the job done for some of us where we are having to resharpen very frequently, as is the case with woodturning.

I have also done a lot of wet cutting of stone with diamond blades and know that high speed wet cutting/grinding has been shown to generate particle laden mists that can also be inhaled and absorbed through the skin and mucosa, so that is not a safe method where there is silica in the material.

The cutting and grinding of 'engineered stone', which is high in silica, will be banned from the middle of this year in Australia. Compliance with adequate PPE and workplace measures may have avoided that, but getting stonemasons to adopt those measures has failed with increasing numbers of them now diagnosed with life limiting silicosis.

The levels of occupational exposure in industrial settings is often very different to what happens in our own workshops, however, I'm just sharing here my concerns about what I do in my own workshop.

What you do in your workshop is your call, your lungs, your wellbeing and your life!