There was a time when I had a complete "dust collector system" in my finish shop.....until one day I had just finished an ironwood handle for a bowie, and immediately following, went to work on a Ti folder frame....at the time the vaccum portion of the dust collector was located in an enclosure on the outside, of the south wall of my shop. I glanced up from the grinder, and notice smoke out the shop window. I about busted down the door getting out there, and by the time I threw open the door on the enclosure, there was NOTHING left of the dust collector. After running for the hose, and about 10mins of dousing everything down, the fire was out. Between the collector and the running the PVC ducting, I'd put about $2,200 into that system.....and in a "DUH" moment, I not only lost the dust collector, but almost the whole shop too!
Moral of the story: In my opinion, a commercial dust collection system has no place in a knifemaking shop. (I'd rather have folks learn from my mistakes....then making the same one(s)
Since averting that "wreck", I installed a homemade "dust sucker" which I built from plywood, and an old 1/2hp furnace blower. It has four disposable furance filters in each side, and works as good, or better then the commercial dust collector.
It hangs in the middle of the shop ceiling.
Another "prong" of my dust collection are simple 5 gallon buckets under the grinders....
If you noticed in the pic, there is a vaccum nozzle right above the bucket on the left....that nozzle goes into a 5 gallon bucket which has about 2" of water in the bottom, and out of that bucket, and into a 5 gal shop vac. The ONLY time that the shop-vac get turned on is when I'm grinding woods, or non-metalic items. The buckets under the grinders catch about 80% of stuff that would otherwise get spread around the shop.