Metal separator for dust collector?

Both woodworking and metalworking machines share my shop space and are only separated by a short space. A shop vac and dust separator are used at my metal lathe and mill to vacuum up chips. It would be real convenient if my primary dust collection system could be extended and used on the metalworking side. I suppose it's possible to use an outlet of the system to support the dust separator in place of the shop vac but some metal filings could get by. Is there a metal separator that is used on dust collection systems? I don't want to get metal pieces mixed in with the sawdust because it is given to one of my neighbors for animal bedding.

How about having two debris bins? One would be for wood, and the other for metal. If you wanted to get real fancy, you could invent sort of a reverse blast gate to switch between the two bins.

Metal chips are generally heavier than wood chips and require a higher velocity of air movement to keep them moving. It would seem doubtful that a traditional dust collection system would have enough flow velocity to keep metal chips moving in large diameter tubes. Also any oil on the chips would likely get transferred to the walls of the tubing and cause wood chips to stick to the walls.

I don't recommend you do that...incidental metal like a screw is one thing, but not major swarf. The cyclone separation itself will make sure the metal doesn't get to the blower, however.

Introducing oil from the metal chips into the ducts is enough reason for me to scrap the idea. I'll stick with the separate shop vac for the metal working machines. I was planning to install a couple of floor sweeps to the dust collector but will scrap that idea too. Metal shavings tend to migrate beyond where they are made and I don't want to get them swept up into the dust bin. Thanks all for helpful ideas and suggestions.

But floor sweeps are one of the best features of having a cyclone... :)

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Originally Posted by Jim Becker

But floor sweeps are one of the best features of having a cyclone... :)

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I don't mind sweeping the floors and using a dust pan the old fashioned way. The real advantage to me in having a fixed duct dust collection system is for now not having to move flexible hose and tripping over them on the floor. I can always add the floor sweeps if that changes.

When I was doing more turning, the floor sweep was totally a no-brainer. Now, my focus is more CNC and things I do at my bench and the floor sweeps in that end of the shop still get a workout, especially for the CNC area. While the CNC has dust collection, there is still a LOT of material that gets blown off the surface with compressed air and has to be swept up during clean-up sessions. Using a broom and pan can work, but it's a less pleasant experience. I suggest you consider putting in one floor sweep in the shop area that tends to get the most debris on the floor and see how you like using it. It's not a huge investment in time and money to do that (you can even use a register boot to build your own floor engaging piece) and if it turns out you don't use it, no big deal.

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Originally Posted by Jim Becker

When I was doing more turning, the floor sweep was totally a no-brainer. Now, my focus is more CNC and things I do at my bench and the floor sweeps in that end of the shop still get a workout, especially for the CNC area. While the CNC has dust collection, there is still a LOT of material that gets blown off the surface with compressed air and has to be swept up during clean-up sessions. Using a broom and pan can work, but it's a less pleasant experience. I suggest you consider putting in one floor sweep in the shop area that tends to get the most debris on the floor and see how you like using it. It's not a huge investment in time and money to do that (you can even use a register boot to build your own floor engaging piece) and if it turns out you don't use it, no big deal.

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Since you recommend it I'll take another look at the floor sweeps. I have a drop on each side of my woodturning lathe. On one side sits a large trash can used for lathe shavings. Do you think I can replace the can with a floor sweep? Would another floor sweep on the other side be beneficial? Below are pics of both areas.
Attachment 438122 Attachment 438123

Dust collection for my 12" jointer has most of the makings of a floor sweep. All I would have to do is make a gated opening in the front panel shown in the pic below. This is located toward the center of my shop along one wall, which makes it a convenient place for a floor sweep. Incidentally, chips would not completely get sucked up under the jointer using the retired single stage Powermatic DC. The new 3hp Oneida cleans the area up completely.
Attachment 438126

Near the lathe, for sure....just use the broom to move the curlies and chips directly to the floor sweep. No picking them up on dust pan at a time. If you get a lot of debris on the other side, sure...consider one there, too. I have three.

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Originally Posted by Jim Becker

Near the lathe, for sure....just use the broom to move the curlies and chips directly to the floor sweep. No picking them up on dust pan at a time. If you get a lot of debris on the other side, sure...consider one there, too. I have three.

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OK, I'll give the one on the trash can side a try. It will free up some floor space without the trash can. Good timing as I was planning to order some more fittings tomorrow morning. The only reservation I have is when this topic came up before some cautioned that sweeping up woodturning shavings would fill up the dust bin too quickly. I suppose it's just as easy to empty the dust bin as the trash can.

Yes, you can fill the bin up quickly with lathe shavings...but the system is picking them up rather than you, so you only lift them once...when you empty the bin. :) Honestly, my J/P will fill the bin up a lot faster. ;)

About 20 years ago I was a foreman for a lead abatement company. We would remove lead paint from steel truss bridges. Since everything coming off the bridge is potentially lead you try not to mix in anything that isn't to avoid paying extra to get rid of it. To remove the paint we would put tarps up to seal off the bridge and blast it with steel shot vs something like silicon carbide. At the end of each day we would use a giant vacuum (think semi trailer with a huge diesel engine driving a root blower). On it there was a metal separator to remove the steel shot.

The way it worked was the vacuum would suck the dust through a horizontal round tube that was turning. Behind the tube was an elector magnet but only for part of the tube. The dust would come in and be directed towards the side of the tube that had the magnet. Steel would collect on the inside of the drum while dust would pass through. As the drum rotated it would turn so the steel would end up going higher (think of like a cement mixer). When it started going back down the other side of the drum there was no magnetic field and it would drop into a chute. It also used a system called a double dump valve. It's a way to remove the steel shot and later the lead dust before it reached the actual roots blower without loosing vacuum (since both would destroy the blower).

But it would only work on steel. Stainless and aluminum clearly aren't going to be picked up by a magnet.