I am concerned by metal dust aswell. I have my grinder in a housing that is big enough to prevent it from saving heat but it is small enough to prevent to much dust from flying around. It looks quiet grey inside after a few grinded gravers. So it seems to hold at least a good amount of dust back.
Besides that i use a bit of oil on the sharpening wheel which binds additional dust.
Small dust particles will fly around for sure. But i dont wear a mask.
I have seen this question came up somewhere else in a youtube video from Shawn Hughes and people tend to lough about health safety efforts. But in my oppinion it is worth it. For me it is not a valid argument to claim that we get polluted by so much hazards anyway. Its not logical for me to add willingly another (possible) threat.
when i rough ground the prelim shaping i did wear a mask. fortunately my entire (way too many) graver collection has been roughed out and properly sharpened. all i do now is touch up work to re do a point
using lindsays' system with a touch of common mineral oil. the dust is trapped. the kind found in drug stores. the grs way i use a dc power supply to power a dc tape transport motor. this goes at relativly slow speed. the dust is trapped by the mmineral oil. now an then i clean the disks with wd40.
yes--err on the side of safety, unless you're absolutly sure the dust is not getting in yer lungs. new cartridges are cheap. new lungs not so cheap. if a respirator is needed, i always use the type utilizing replaceable cartridges, not the flimsy paper ones.
A few things to consider;
1) are you sharpening by hander power? Hand sharing would throw less dst than power.
2) what metal are you cutting? Carbon steel and tungsten carbide have different toxicity
3) are you sharpening wet or dry? A little water or oil can reduce a lot of dust
4) how much are our sharpening? Touching up an edge is very different hand grinding new graver from a blank.
We all know that grinding away metal from gravers creates particulates. Some of these come from the metal of the graver, others from the abrasive materials used for sharpening. Personally, having my Power Hone within close proximity of my work space is convenient.
Due to the recent COVID Pandemic, many of us have learned a great deal about face masks. For anyone interested, here are two links to articles on the efficacy of face masks. The first one, admittedly a bit technical, is from the Journal of Thoracic Disease; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5906272/
Obviously, it’s a good idea to keep the air in and around our workspace clean and free of contaminants. This is especially true for those of us using oil-free compressors and related tools.
One reasonable and cost-effective solution for me, was an inexpensive 20” x 20” box fan, and a HEPA furnace filter of the same size. Attaching the filter to the inward flow side of the fan with a little Duct Tape, and setting it on ‘low,’ in the proximity of my Graver Hone, (pulling air away), helps to remove a great deal of contaminates from the atmosphere in my work space.
Hopefully, this suggestion might help us all breathe a little easier.
You could get creative and build something such as this, hooked up to a shop vac connected to the power hone and cart frame via zip ties and used for roughing out the blanks, air born particulates are short lived.
The mask might be a good idea, besides keeping the equipment a far as possible from your face. I am using the GRS diamond wheels. My first cautionary routine is the placement of the equipment. It must not be on the work bench(!), mine is on a stool beside the bench. Second, I have the sharpener in a plastic box to prevent the metal particles from spreading and contaminating the place.
When I clean the sharpener, the box, or wash the diamond wheel I am wearing latex gloves. I clean the sharpener and the box with wet wipes to prevent the contaminants to go airborne.
I clean the diamond wheel with an eraser while running warm water over it.