I talked about it in my last blog post, but I wanted to dedicate a post to this subject as I figure it will be easier to find that way.
My now old, circa 2009 Central Machinery 2HP dust collector that I bought from Harbor Freight on sale and with a 20% off coupon, has always worked okay, but I want more than okay. I wanted it to work well, if not great, and there are some simple modifications that go a long way to making this a much better unit.
The modifications to the dust collector are....
- Replace the 20 micron bag filter with a .5 micron cartridge filter. This actually filters the dangerous dust, AND provides superior airflow. I went with a Wynn Environmental 35a spun bond poly long ago, but there are newer less expensive options nowadays.
- Replace the tiny stock impeller with an impeller that is basically the biggest impeller I can fit in the housing. There are 2 that I know of, one from Rikon that has been next to impossible to get, and when available costs almost as much as the dust collector, and one from Wen, the 3403-22 Turbofan. I went with the Wen. All of the online tests of this modification alone show increased CFM of at least 35%, and static pressure (vacuum) increases of at least 10%. There is an increased startup amp draw, but it is not huge.
- Upsize the inlet flange from 5" to 6". For now I will use a 6x4x4 splitter, but long term idea is to rip out the dual 4" system, and run a single 6" main, and reduce to 4" or 2.5" as close to the tool as possible.
- Set up a cyclonic separator of some sort. I am looking to save space, so instead of staying with my 55 gallon Thien separator, I am going to go with a Thein baffle in the separator ring of the dust collector.
To do these modifications I will need / have the following materials.
- .5 micron Wynn 35a spun bond poly (washable) cartridge filter. This model is no longer available, and Wynn has gotten expensive recently. In lieu of the Wynn filter, the Donaldson P181038 filter is reported to be a direct equivalent to the Wynn 35a with a much lower price tag. https://amzn.to/3DMrJfs You may want to use Wynn's floating gear latches to secure the filter, or possibly come up with your own rig. https://wynnenv.com/products-page/woodworking-filter-pricing/fgl-l-4/
- As far as I know, the current Central Machinery 2 HP dust collector is more or less the same as the old one, but with a different base, and paint color. https://www.harborfreight.com/2-hp-industrial-5-micron-dust-collector-97869.html?_br_psugg_q=dust+collector
- The Wen impeller in November 2021 ran me $35.00 delivered. https://wenproducts.com/products/340...530916dc&_ss=r
- I am using a Hydrofarm AC6F 6" flange that will need to be drilled to match the Harbor Freight mounting holes. This will upgrade the inlet flange to 6" allowing connection of course to a 6" ducting system. https://amzn.to/3nFicRJ
Unlike most Harbor Freight dust collector upgrades, I am not going to use a separate cyclone or seprator, but instead use a Thien cyclone separator in the separtor ring of the cust collector. There is a good but now old write up on Phil Thiens forum regarding this specific modification. The standoffs the original poster used are a bit on the big side, but the idea is right there. http://www.jpthien.com/smf/index.php?topic=145.0
The process? Starting with the impeller and flange upgrade.
- Unplug the dust collector, or at the very least, removing the safety key from the switch. We do NOT want the impeller to start moving while our hands are in there!
- Remove the inlet hose from the flange.
- Remove the attachment screws for the flange. I placed mine in a magnetic bowl while working to keep them from wandering off. The gasket may stick to the flange, or the impeller housing. Keep it on either for now. IF it stays on the impeller housing, just leave it there.
- Using a 5mm allen wrench, loosen and remove the retaining screw turning clockwise. This is a counter threaded screw so righty loosey here! Keep the trust washer with the screw in the orientation it came off.
- Using a 3 jaw puller, CAREFULLY attach the puller to the flange lip of the stock impeller. And run the puller pressure screw in, making adjustments to your puller to be sure you get a succesful pull all the way until the impeller comes off.
- Rotate the motor shaft such that the keyway, and retaining key are pointed directly up.
- Coat the inside of the bore and keyway of the new impeller with a light oil. I used air tool oil as it was right where I was working.
- Align the new impeller bore / keyway to the key / shaft, and wiggle it a bit until it just barely starts to go in. You are going to need to drive it home though.
- Using a rubber mallet, and a piece of scrap wood as a striking surface, drive the new impeller onto the shaft, striking the wood, and using the wood to push the impeller hub, until the impeller is fully seated.
- Rotate the impeller several times insuring no operational interference..
- Match original flange to new flange back to back. Using silver sharpie or similar, transfer screw hole locations.
- Using center punch, and supported on an anvil of some sort like a machinists vice, dimple each screw hole location in the new flange, This will keep your drill bit from walking off.
- Size up, and select the proper drill bit for drilling metal. Using proper PPE drill the holes.
- Transfer the gasket if it is on the old flange, if not move to installing new flange on the impeller housing.
- Replace safety key and / or plug dust collector back in. Turn it on and verify function.
- Attach new ducting, or adapter to make it work with existing ducting.
- Remove the original bag filter, and support bar. These can go away now.
- IF your filter does not have gasket material on the bottom, obtain some foam weatherstrip material and attach it. You NEED a gasket there!
- Install filter per MFG instructions, or at the very least, using bungee cords, strap that sucker down. I linked the Wynn clips. My old 35A uses tiny turnbuckles on the inside to hold it in place.