update: The DC setup I showed in this thread has been retired and replaced by a 2hp Harbor Freight DC unit. I still use the chip collection drum. On sale, and with a 25% discount coupon the HF was $187, plus $140 for a drum filter for the shop unit. Far more effective than what I showed in the post on this thread. Should still put in the Thein separator, but haven't gotten around to it. The old setup was not bad, but not nearly as effective as the HF unit.
You can replace the HF impeller with a larger metal one from Rikon but you don't want to let chips hit it--so a chip separator is required. BTW, the chip collector will hold most of the sawdust, so you must empty it regularly. I have a 30 gallon fiber drum for this purpose, and try to empty it when it gets half full. If you are doing a lot of production, you'll probably need a larger drum.
And I would then consider drilling a large hole and cementing a glass panel under the hole so you can check dust levels. If you build a Thein separator, you'll need to work out a way to check the sawdust level. One method is to drill a half inch hole through the top and Thein, and place a dowel through it. Put a small "foot" on the rod. Place a mark on the dowel to indicate the empty level, then pull it up and mark the full level in red. Makes checking depth of sawdust quick and easy--pull up, drop down to the top of the sawdust and you know. You get a reduction in suction if it gets too full.
I have a small shop, so the drum filter is a must. it filters down to 1 micron and the relatively clean air returns to the shop so I don't lose heat in winter or AC during summer.
One other thing, the shower curtain works extremely well on the sliding miter saw. But you can increase its effectiveness by pulling the blade forward to make a shallow cut first, then push back to cut through the rest. The first pass makes a channel so FAR MORE sawdust shoots back into the curtain. The other change is instead of having sawdust drop down into a box, the curtain is drawn down and taped to a 4 inch fitting, attached to a hose with leads back to a fitting where my main DC hose quickly attaches. My shop is too small for permanent piping and tools are arranged so about 12 feet of hose reaches every tool. There is also a smaller hose over the workbench that can drop directly into the main DC hose.
The system is simple and in the end, cost no more than all the stuff I've purchased to try to cobble together a system that didn't hold a candle to the HF unit. I also installed a WEN brand air cleaner, about $130 from Amazon, which has a timer and speed control. I leave it running for a couple of hours after making cuts to thoroughlyfilter all the shop air. It has made it really nice to work in the shop. But I still wear a surgical style face mask at the least when I work in there, and a fan driven filter mask while making cuts. I like my lungs.
Hope this helps someone make a good choice on dust collection.
The more I do, the less I accomplish.
Last edited by DesertRatTom; 02-24-2017 at 12:32 PM.
Reason: details, correction