The idea is to reduce tools to the essential so that I: 1) can load and unload everything every day, 2) don't have to pull a trailer everywhere I go, 3) reduce the setup and teardown time to as little as possible.
A small aside to those reading this wondering why I load everything up every day. In the last year I've lost over $300 worth of tools from leaving them overnight. One of our guys lost everything in one night. Stolen off the jobsite. Locks and chains cut through, everything packed up and *poof* over $2,500 gone. I can't afford losses like that. What little I've had stolen is hand tools, and a ladder. I'd die of shock if someone stole everything I had. If I survived, I'd soon after be in jail for murder.
I like my tools. I'd like to keep them.
But why no trailer? I don't make that much, and anything that goes in the gas tank, is by definition not in my pocket.
Back to our story. I've been thinking about picking up a dust extractor, and have had my eye on the Makita because it runs so quietly. The common reports of the remote start switch simply stopping is bothersome, but the price tag is the real kicker. The DeWalt, The Bosch, the Makita, the Festool are all, imho, unreasonably expensive for what they are, and I could really care less about a filter autoclean feature. Give me a tool that works and I'll use it. Give me a reasonably priced tool that works great and I'll buy two. Charge me out the ass for a half-assed product and there's no way I'm touching the fkking thing.
So I was discussing the possibility of building one with someone who's had some experience at this, as I'm not above learning from someone if they're willing to share their wisdom. The problem, as I saw it, was that with more than one person on site (meaning more than one array of tools running) energy usage becomes a major concern. I'd really rather not burn my motor on my table saw and 12" slider up. With only one working circuit in the house while we're there, running and starting watts become one of your daily concerns. Most I've worked with though, don't give it a second thought. They just burn up tools like someone else is paying for them.
And so, 400 watts was the number I was building to. 400 running watts isn't a lot of power. At 110v (most homes run around 120v, not the rated 110v) that's only 3.64A you can safely draw and not exceed 400 watts.
Wait, why 400? My table saw starts at 1800 watts. A 20A circuit is 2200 watts. 1800+400 is? Most 20 Amp breakers will trip at 2400 watts.
That 400W is a harder limit than one might expect.
Any dust extractor that's paired with a high running watt table saw must be conscious of energy usage. Most shops have separate circuits for dust collection. Running those big motors ain't cheap. In a jobsite setting, there are only a handful of times when 220v is available, or more than one lonely, overworked circuit is on hand. So, if I wanted dust collection it had to be economical dust collection, if not downright frugal.
It was my friend's suggestion that a 400W dust extractor that could do 50cm of static pressure was impossible. The impeller, he said, would have to be so large to produce 50cm that it would far overload a 400W motor. I kind of took that as a challenge.
I knew that universal motors could be reigned by a variable voltage controller. When you change the voltage, but the amperes remain constant, wattage is reduced as well as voltage is a multiplier in the energy equation. So, a voltage control that runs a universal motor at a lower voltage (and speed) was entirely possible. Was the 400W barrier possible? Yes, indeed it was. Would it break the 50cm ceiling? We were about to find out.
I had a couple reclaimed vacuum motors with backwards impellers already attached, so I tested a few of them.
That seemed to work surprisingly well. I went on to build my extractor based on a few designs I had seen around youtube and the web in general. I wish I could thank all the contributors to this design that I ran across. Without their efforts, I would not have built my own.
I spent the weekend putting mine together. This following video is v2. V1 was just a box with a filter, which worked, and worked well, but the box filled up amazingly fast, particularly during the build of some large barn doors for a client north of Edmond.
You can see my buddy Jon mugging for the camera there. He's a great guy. Learns quickly too. For reference, Jon is over 6 ft. These doors are 113" tall, and the largest of the two is 94" wide. The #2 pine 1x12's that make up the field on each door had to be tongue-and-grooved. #2 twists and bends so much according to temperature and humidity, just moving them inside would have showed cracks between the boards over 1/8". The builder was adamant that this was not to happen on his doors. Understood.
I set these up for a 3/8" t-n-g with a 1/4" show. Should be easy to touch up when they shrink. Paint is not my circus, not my monkeys. Thank you, God.
V1 had to be emptied 3 times during the routing (done on a router table). It worked, but was a pain in the ass. That's why v.2 received a Thien baffle. Thank you, Mr Thien! These are dead simple to build. It works great. I even tested it with a flashlight in the bucket so I could watch the heavy stuff swirl to the bottom, which is really cool, btw.
So, with my weekend gone, I finished my build.
Works like a charm. I can get more than 50cm of suction out of 400W running through a Thien baffle and a 12x24x1 furnace filter. The baffle and filter keep the throughput clean enough that I don't have to worry about my impeller imploding. Well, exploding, or whatever happens when a piece of debris with some mass to it hits a thin piece of aluminum at roughly 65mph (the real reason dust collectors use robust radial fans that require big motors to drive them at comparatively low rpm).
RPM is a major factor in the performance of backwards-vaned impellers. They function best at high rpm, which is also why your shop vac is so damned loud. It's taking lots and lots of little bites of air, and the air is screaming at each nip. Lots of little bites equals big chuck of flesh. Mosquitos know, you need not be big to be really annoying, or have a big impact. You just need lots of friends.
My 400W Jobsite Dust Extractor build isn't finished yet. I have to make a handle and a transport strap for it. That's about it, though. And some teal paint. Can't skip the teal paint.
You know, I have a 2.4A 3450 motor. I could build an induction variant. But then, what I've got works, and works well. Why bother? It'll be just as loud with an impeller spinning at 20k rpm.
You know, I have a 2.4A 3450 motor. I could build an induction variant. But then, what I've got works, and works well. Why bother? It'll be just as loud with an impeller spinning at 20k rpm.
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