Give me Your Opinion about this Idea

[Mike Henderson]

For those who have a DeWalt 735 planer, you know that it has a fan inside the planer that sucks up the swarf, and then spits it out the dust collector port. Seems to work well.

I bought a Festool Kapex and tried hooking it to my whole shop dust collection system but the swarf collection was not very good. So I got a small shop vac and hooked it to the Kapex and the swarf collection is much better. But the small shop vac fills up too quickly.

Suppose I was to remove the filter from the shop vac and then hook my big dust collection system to the exhaust of the shop vac. Seems that the system would work in a similar manner to the DeWalt 735 planer. The shop vac would provide the high volume of air through the 35mm hose and the swarf would be spit into the big dust collection system.

Can you see any downsides to this? Seems that the major issue is whether the swarf will go through the shop vac fan okay.

I know some people might suggest putting a small separator ahead of the vac but I don't have room for that extra container.

Mike

[Lee Schierer]

I don't think that the fan in your shop vac is going to like having all that swarf flowing through it. Most shop vacs suck the air out of the canister through a filter. Removing the filter would let dust and debris get into the fan which would not be good. About the only time you can safely remove the filter on a shop vac is when you are sucking up liquid.

Some people have success by putting small cyclone separators on trash cans ahead of their shop vacs to handle larger volumes of shavings.

[Frank Pratt]

I wouldn't want to try that on an expensive vac, but maybe on a Ridgid or something like that. The dust from a miter saw is pretty fine & I think it'd go through a vacuum OK.

My miter saw dust collection is great cause I've got it in a cabinet closed in on 5 sides with an 8" duct sucking ALL the dust out. But I've thought about doing that with the overhead collection on my SawStop. For the most part it's quite good, but it has a pretty small connection & the DC has a hard time drawing much flow through it. My fear though, is that tiny off cuts could get sucked up & through the vacuum.

[Jim German]

I don't think it would be an issue. Probably wouldn't do good things for the life of the shop vac, but they are pretty much disposable.

[Yonak Hawkins]

Mike, is it that the reduced suction of the shop vac does a better job with the swarf than the shop system ? If so, could you adjust the suction of your shop system ? Otherwise, in what way does the shop vac work better ?

[Keith Weber]

Mike, what if you were to gradually step down the pipe size of your shop DC near the Kapex so that it speeds up the speed of the airflow, and then hook that directly to the Kapex as you do with the Shop Vac? Not sure how many cfm a shop DC would pull through a small hose compared to a Shop Vac. Surely someone here has tried that already and would know if it would work or not.

[Dan Friedrichs]

You can't build some sort of "chute" behind the saw that catches everything well enough with just the DC? If not, sure, why not try it? I'd (personally) love to hear how it works out. What harm could it possibly do to the shop vac? I guess it depends on how the impeller is housed (relative to the motor). If there is a sealed bearing between them, seems like the risk is low. If the whole motor rotor and impeller are all one exposed piece, maybe it's worse (I have no idea how shop vacs are built, though).

I guess that assumes you only cut wood on the saw, and generally only produce fine dust. Maybe install a wire mesh in front of the inlet to avoid small offcuts from hitting the shop vac impeller. Likewise, I've often made long, stringy swarf on the miter saw, but only from cutting aluminum or plastic.

[Doug Garson]

Like the others I'd be concerned about the shop vac fan with no upstream filter and suggest some form of pre-collector. Also I think your comparison of the shop vac vs dust collector is backwards. Shop vac would be higher suction pressure and lower flow volume than a dust collector. So it's the higher suction not flow volume that helps swarf collection on the Kapex.

[Andrew Pitonyak]

I recommend against this (for not particular informed reason other than I expect the shop vac to not be setup for it.

I have seen the 735 used outside with no dust collection and it spits stuff everywhere.

I connected mine to my primary dust collection (A jet something or other) and when I turn on the planer, the bag inflates because the blower is so strong.

I vaguely remember hearing that a small hose cannot keep up with the volume generated by a smaller hose.

So, what if you just connect something like a garbage can with an input and an output so that the large can can take the majority of the shavings. You can then have the output connected to your shop vac. I expect that the fan in the 735 will do most of the work here.

[mreza Salav]

If the only issue is that the shopvac fills quickly (which I find it must be a very small, given that it takes a LOT of cut to generate substantial amount of saw dust from a miter saw) why not change the bucket to a larger one? You can still use the shopvac on that larger bucket; just make an adapter out of plywood or MDF to fit between the two.

[Dan Schmidt]

Get a dust deputy.
http://www.oneida-air.com/category.asp?Id={CC6B6F2A-E3D7-4F18-A53C-B5C357DFE131}

[Prashun Patel]

how big's your shop vac? Can you just get a bigger one?

Or, can you use a drywall collection bag inside your shop vac to make frequent emptying less painful?

Do you have room ABOVE the shopvac for a preseparator? There are rube-goldbergish contraptions to minimize the space the preseps take. I know you said you don't want one, but besides making container emptying less painful, the filter performs better for longer than without it. (I'm sure you've considered that, tho).

[Peter Aeschliman]

I agree with those who are saying that the shop vac motor is not designed for unfiltered dust. It's not the same design as a dust collector, where there's a TEFC (totally enclosed, fan-cooled) motor and the dust never touches any part of the motor. It pulls ambient air through a fan to cool the motor. Shop vacs get their cooling air from the dirty air that it is sucking up. That's why the filter is upstream from the motor.

Have a look at this. Shop vacs typically use a "flow-through" motor. It's important to filter the air before it touches the fan and motor assembly.

http://www.westernwholesalevacuums.com/central-vac-buyers-guide2.html

The central vacuum system's equivalent of the dust collector design is the tangential bypass motor, which could be configured just like a scaled down version of a central dust collection system (dirty air goes through the fan/impeller, and is blown into a filter).

Also, I'm not sure whether your central dust collector would over-drive your shop vac, or whether it would have the opposite effect. I'm not sure I really follow the logic- it seems you're saying that you want the high static pressure of teh shop vac, but don't want the dust to accumulate in the shop vac bin. Honestly, I would just live with emptying your shop vac. :)

[Dan Friedrichs]

How about hooking your DC via a blast gate to the shop vac's existing bin? Makes emptying the bin much easier :)

[Myk Rian]

I have seen the 735 used outside with no dust collection and it spits stuff everywhere.
He isn't discussing the DW735. It's a Festool Kapex saw.

[David Kumm]

As Mike found out, a DC won't pull enough air through a small port because it is designed for low pressure so a shop vac impeller designed for high pressure is what is needed. Are you thinking that you could keep the filter, cut a hole in the side of the shop vac and put a 4" DC hose in it and run it with the vac on or only after it is shut off? Dave

[Mike Goetzke]

I had a 735 several years ago and seem to remember removing the internal fan (like many others) when using a dust collection system works much better.

Mike

[Jerome Stanek]

I would look at adding a Thein separator with a large collection barrel to the shop vac

[ken masoumi]

Get a dust deputy.
http://www.oneida-air.com/category.asp?Id={CC6B6F2A-E3D7-4F18-A53C-B5C357DFE131}
+1.that's how I collect the dust from my DW735, I disconnect the hose that goes from DD to the shop vac(otherwise some dust still gets inside the shop vac), the force from the planer fan is so powerful that I don't even need to turn the vac on.

[Jim Dwight]

I use my shop vac with a dust deputy for everything right now. I don't have a connection for anything on my AP-10 planner so I just sweep up after it and then vacuum. I have a port on my jointer but it's 4 inch and my 1hp DC couldn't keep up so I'm sure the shop vac won't. I think I'll have to take the port off and sweep up.

But with the dust deputy, I have yet to need to empty the shop vac and only occasionally clean the HEPA filter. Even drywall dust is mostly captured by the cyclone. I makes a huge difference. If I do a DC, it will also get a cyclone. Life is too short to be cleaning a filter in a DC all the time.

[Mike Henderson]

As Mike found out, a DC won't pull enough air through a small port because it is designed for low pressure so a shop vac impeller designed for high pressure is what is needed. Are you thinking that you could keep the filter, cut a hole in the side of the shop vac and put a 4" DC hose in it and run it with the vac on or only after it is shut off? Dave
I wasn't thinking that, but some people made comments similar to that (your's was the most direct) and I'm considering that now. If I put a blast gate between the DC pipe and the vac, and keep the blast gate closed when I'm using the vac, I won't lose suction pressure in the vac. Then, once in awhile, with the vac off, I can turn the DC on, open the blast gate and suck the swarf into the DC.

The other reason I like the vac hooked to the Kapex is that I have it connected so that it turns on automatically when I turn the Kapex on. I used to often use my old miter saw without turning the DC on because I was in a hurry and I was just going to make a small cut (at least that's what I told myself:)).

I'll cut a hole in the bottom of the vac and make a connection to my DC. I'll let you know how it works out.

Mike

[I appreciate the suggestions for putting a "Dust Deputy" type device between the saw and the vac but I really don't have the room.]

[Rick Potter]

Mike,

That may remove the contents of the vac, but I suspect the filter will still clog quickly.

[Andrew Pitonyak]

He isn't discussing the DW735. It's a Festool Kapex saw.


hang on, I need to go bang my head against the wall a bit. Not sure how I missed that.

[Al Launier]

Rather than try an alternative to your dust collector you might want to consider using the dust collector with this in mind. I use the Dust Right hose/accessory system & for my miter saw I use http://www.rockler.com/tabletop-dust-fitting for which I attached to a made a box that encloses the rear of the MS. Works well!

[Duane Meadows]

I agree with those who are saying that the shop vac motor is not designed for unfiltered dust. It's not the same design as a dust collector, where there's a TEFC (totally enclosed, fan-cooled) motor and the dust never touches any part of the motor. It pulls ambient air through a fan to cool the motor. Shop vacs get their cooling air from the dirty air that it is sucking up. That's why the filter is upstream from the motor.

Have a look at this. Shop vacs typically use a "flow-through" motor. It's important to filter the air before it touches the fan and motor assembly.

http://www.westernwholesalevacuums.com/central-vac-buyers-guide2.html

The central vacuum system's equivalent of the dust collector design is the tangential bypass motor, which could be configured just like a scaled down version of a central dust collection system (dirty air goes through the fan/impeller, and is blown into a filter).

Also, I'm not sure whether your central dust collector would over-drive your shop vac, or whether it would have the opposite effect. I'm not sure I really follow the logic- it seems you're saying that you want the high static pressure of teh shop vac, but don't want the dust to accumulate in the shop vac bin. Honestly, I would just live with emptying your shop vac. :)

No, the dirt does NOT go thru the motor! it does, however go thru the impeller and housing! Not a good thing, as the impeller, nor the housing is designed for that. Any large chunks(like bigger than a 1/4") will likely destroy one or both. The dust deputy type pre-filter is a better idea , but leave the filter in the shop vac also.

You will notice in the pictur you linked to, that there is a fan on the top of the motor... that is what cools the motor, not dirty air. You may get a very small amount of very fine dust thru/around the seal, but it will be minimal. Else the motor will not last long! I have changed hundreds of motors and impellers in shop vacs during my career.

[Bill Sutherland]

My Kapex is hooked to Dust Deputy and shop vac and it's perfect for me

[Michael Dye]

OK, I'll bite. What is "swarf"? Obviously an acronym for something, but I am at a loss.

[Prashun Patel]

Swarf?

It's probably more onomotopoeia (doh, SNAP!) then than F.L.A. (five-letter acronym)

[Duane Meadows]

According to Merriam-Webster... "Definition of swarf. : material (as metallic particles and abrasive fragments) removed by a cutting or grinding tool." Hmm, wonder why they left woodworking out of that definition? This day and age we should probably be offended by that!

[Mike Henderson]

OK, Woodcraft had a sale on the Dust Deputy cyclone and I decided to give it a try. I had an unused 5 gallon pail with a top which I mated to the Dust Deputy. I hated to give up the work/storage space but this seemed like the best solution.
334948 334947

I have to say, the Dust Deputy WORKS. I was amazed at how well it bypases the swarf into the bucket. I'm sure a bit gets to the vacuum but I won't have to clean the vacuum out very often.

Thanks to everyone who recommended this approach. It works well.

Mike

[One thing I couldn't find was a short vac hose. That's why you see the hose all curled up by the vac.]

[Andrew Pitonyak]

[One thing I couldn't find was a short vac hose. That's why you see the hose all curled up by the vac.]

Some hoses have connectors that screw on, which allow you to cut the hose to length. I don't remember which of my vacuum hoses does that, but I can check if you like. If my memory serves me correctly, it is an orange hose that I purchased from sears years ago, so I may not have an actually manufacturer, but knowing that some do allow this...