Bandsaw dust collection question

[Mark Gibney]

What do you think is the better approach to bandsaw dust collection just under the table, next to the lower guide?
- to use the funnel in this photo here
- or to make a shroud that wraps around the area under the table

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The 4" hose will go to a 3 hp cyclone.

I suspect a "shroud" will be the better option, but if someone tells me the funnel will work just as well I'll happily put that time saving to good use.

The bandsaw is a Davis & Wells with a cast iron frame, so it doesn't have the sheet metal body that would allow me to suck the dust through a port on the lower housing.

thank you, Mark

[John K Jordan]

What do you think is the better approach to bandsaw dust collection just under the table, next to the lower guide?
- to use the funnel in this photo here
- or to make a shroud that wraps around the area under the table

423450 423451

The 4" hose will go to a 3 hp cyclone.

I suspect a "shroud" will be the better option, but if someone tells me the funnel will work just as well I'll happily put that time saving to good use.

The bandsaw is a Davis & Wells with a cast iron frame, so it doesn't have the sheet metal body that would allow me to suck the dust through a port on the lower housing.

thank you, Mark

I use three dust pickups on my bandsaw. A port in the corner of the bottom cabinet, a plexiglas shroud around the lower bearings, and a positionable duct on the top of the table to catch a lot of the dust that gets thrown across the table with "skimming" cuts.

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There is almost no dust that accumulates inside the saw. I think anything you can build to surround the lower guides and connect to a duct will be a big help.

JKJ

[Edwin Santos]

I'm familiar with your bandsaw (beautiful saw BTW) and I understand why you do not have the option of a lower dust collection port.

Because you are connecting to a powerful dust collector, I think the funnel idea should work. My only hesitation would be the loss of air movement by reducing a 4" line to the narrow tip of the funnel. Doing this will increase the static pressure but decrease the CFM which is not the ideal trade-off in dust collection. I would keep your "funnel" to the biggest diameter you can still fit in the location pictured under the table. I would also try to orient the pick-up so the dust is flying towards it as much as possible. In other words, the dust is flying downwards with the direction of the blade. I would keep my pick-up low and at an acute angle to the blade, maybe 30 degrees.

Think of the dust as a car that should be going down an off ramp on the highway, not making a right hand turn. I hope this makes sense. The white port in John's picture is a good illustration of what I am trying to describe.

My guess is you may have to fool around with the angle and position, but in the end it will work well.

Hope this helps,

Edwin

[Alex Zeller]

For a short period of time I had a Harbor Freight 14" bandsaw. The port on it was worthless. What I did was similar to what you are talking about. I just put a spare flexible hose from a shop vac right under the table. I had that connected to my 2hp dust collector. I would say it caught 90% of the dust. I didn't spend much time trying to improve it as the saw was free and wasn't long for my shop. But I think if you can forget about a better idea is the shroud or to have the hose on both sides of the blade towards the front. Do you tilt the table? If so a shroud that can work well with the table at any angle might be more difficult. You might also want to look into adding a brush on each side of the blade near the guide to help the DC remove it.

[Mark Gibney]

Great feedback. I think something to surround the guide like John has done makes sense. And it also makes sense that the narrow tip on my funnel cuts down on the CFMs as Edwin says.
Alex, what kind of brush is the best for what you're saying?

[Matthew Hills]

Rob Cosman's video on undertable dust collection is also reputed to work well (although I believe this is designed to work with a vac that might deal better with the small-diameter pipes better):

https://www.youtube.com/watch?v=Ut_tqnqrRww

[Malcolm McLeod]

Great feedback. I think something to surround the guide like John has done makes sense. And it also makes sense that the narrow tip on my funnel cuts down on the CFMs as Edwin says.
Alex, what kind of brush is the best for what you're saying?

One other thing to keep in mind - something under the table, surrounding the lower guides, could impede your ability to tilt the table. I'd try to either make it easy to install/remove, or attach to the trunnion and swing with it when tilted.

[Mark Gibney]

Rob Cosman's video on undertable dust collection is also reputed to work well (although I believe this is designed to work with a vac that might deal better with the small-diameter pipes better):

https://www.youtube.com/watch?v=Ut_tqnqrRww


Good video, and really interesting to get a peek into Rob's shop.
I just now looked at a few youtube videos on this, and there are some interesting solutions. Many of them connect to a shop vac, like Rob's setup, and not to a cyclone dust collecting system.
Is one better than the other in terms of the actual amount of dust collected?
The attraction of using a shop vac is that it's more convenient, uses less power, and is not as noisy. Any downsides?

[John K Jordan]

One other thing to keep in mind - something under the table, surrounding the lower guides, could impede your ability to tilt the table. I'd try to either make it easy to install/remove, or attach to the trunnion and swing with it when tilted.

Inhibiting table tilt is an issue. In my case it doesn't matter much - my plastic under-table shroud is held with small magnets and can be removed in a heartbeat. Also, I almost never tilt the table. Those few times I wanted an angled cut a wedge on the untilted table worked.

Unless my memory fails me, I think last year Derek Cohen made one with a horizontal tube mounted so the blade intersected the tube with a hole in the top and the duct connected to the end. I can't remember if it was posted in SMC or another forum. There was some discussion. Maybe a search would find the thread.

JKJ

[Lee Schierer]

Rob Cosman's video on undertable dust collection is also reputed to work well (although I believe this is designed to work with a vac that might deal better with the small-diameter pipes better):

https://www.youtube.com/watch?v=Ut_tqnqrRww

I noticed that he had considerable sawdust on the top of the table that was carried all the way around by the blade. His design would work even better if he left the far end of the tube open so that he would get more air flow across the blade to pull away all the saw dust. The thin slot he has for blade entry doesn't allow much air flow. Also not that his Fein vacuum uses a separate air flow to cool the motor so restricting the air flow through the hose doesn't affect motor cooling. Shop vacs that use the air flow through the hose to cool the motor would tend to overheat.

[Andrew More]

Is one better than the other in terms of the actual amount of dust collected?
The attraction of using a shop vac is that it's more convenient, uses less power, and is not as noisy. Any downsides?

They're just different. Dust collectors collect a large volume of air, but have less static pressure. A shop vac tends to have much less air flow, but much more static pressure. So dust collectors are like Semis, while Shop Vacs are more like cars.

Here's a good article comparing dust extractors.
https://www.toolboxbuzz.com/head-to-head/best-dust-extractors-head-to-head/

They show a tested CFM of between 50-172 CFM. Most Dust collectors will show 5-10x more CFM. My Grizzly is rated at about 1072 CFM, and the 5 HP monsters from Clear View will hit 1700 according to their fan curves.

They also show a static pressure of 50-100 cubic inches, while a dust collector is going to have about 1/10 of that. My Grizzly is rated at 10", not sure what the Clear View hits, probably about twice that.

When going through a very small opening (1-2") a shop vac works best, while in a larger opening (3-6") a dust collector works best.

When collecting fine dust a larger air flow is better than a smaller air flow, since it will allow more of the air around the shroud to be collected. However, some tools by their design work better with a smaller port. Among those are the SCMS, Circular Saw, Hand Held Sanders, and the port on a lot of band saws.

Most shop vacs do a poor job of filtering fine dust, as a result they'll act as chip collectors, while throwing the fines back into the air. They also have a nasty habit of clogging up the filter pretty quickly with some types of dust. Thus I would not buy a normal "shop vac".

Dust extractors are essentially the same as shop vacs, but designed to filter the fine dust out. They often have self-cleaning filters, and other features, like turning on when the tool turns on. They're primarily aimed at jobs involving concrete drilling, grinding and cutting, where OSHA recently imposed strict standards collecting on the fine dust generated. Dust Extractors also start at ~$500 and up, Shop Vacs can often be had for $50-100.

Dust collectors typically do a better job of collecting the fines, even the single stage collectors with bags. While Bill Pentz is correct that the baggers will all the fines through initially, they'll get "seasoned", and allow fewer and fewer through with usage.

[glenn bradley]

Since adding an under the table collection point I don't use the lower cabinet collection point at all. Throttled the gap at the entrance to the lower cabinet:

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Built a little box with a couple of 1" magnets on it:

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I sticks on here:

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I collect from right below the table and at the entrance to the lower cabinet:

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I sealed the lower port in the bottom cabinet and this is how much spoil gets past after a few months of use:

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[Mark Daily]

I made this dust collector using 1” PVC pipe. It is held underneath the table with 2 rare earth magnets and connects to my shop vac which is equipped with a bag and HEPA filter. According to my Dylos meter, there is less than 100 large or small particles escaping the vac when connected to the band saw, ROS sander, etc.

It works so well I no longer use the factory dust port. Under 200 particles when in use.

It was inspired by Rob Cosman.

Bandsaw is a Grizzly G0555 14”.

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[glenn bradley]

I made this dust collector using 1” PVC pipe.

What a great setup for a 14" saw. I bookmarked this to make one for my Dad.

[Randy Heinemann]

What do you think is the better approach to bandsaw dust collection just under the table, next to the lower guide?
- to use the funnel in this photo here
- or to make a shroud that wraps around the area under the table

423450 423451

The 4" hose will go to a 3 hp cyclone.

I suspect a "shroud" will be the better option, but if someone tells me the funnel will work just as well I'll happily put that time saving to good use.

The bandsaw is a Davis & Wells with a cast iron frame, so it doesn't have the sheet metal body that would allow me to suck the dust through a port on the lower housing.

thank you, Mark

I have a 1 1/2 HP Oneida cyclone and use a split collection method via a Y connection; a 4" connection to the bandsaw's regular port and a tapered attachment with a 2 1/2" articulated hose from the Y which is directed right under the table insert (around where the lower guides are). I bought the tapered head and 2 1/2" hose from PeachTree. I believe it is sold as a dust collection set for the drill press, but it works well for my bandsaw. After installation, my dust collection is at anywhere from 90% on up, depending on what I'm cutting. While I like the idea of constructing an enclosure below the table, at this point, I feel I get excellent results without that additional effort.

[Bill Dufour]

My startrite bandsaw has a rotating brush to wipe chips off the blade. It is non powered so friction move sit around.
Bill D.

[Bill Dufour]

On my 14" delta BS I put a piece of split wire loom over the blade slot on the left. It helped reduce the dust thrown up into the air by the blade on it's way up. It pulls off easy for blade changes.
Bil lD

[Alex Zeller]

I have used old tooth brushes in the past but found that mounting them in a way they don't move to be a little difficult. I like that PVC idea. I should be possible to mount the brushes too the PVC. I think the commercially available ones are cheap.

[Bruce Wrenn]

Wood Magazine had a "Top Tip" (mine) using a 4" sewer Tee under table. One side was blocked off, and tee was held in place with a couple Rockler blast gate mounting brackets. Been over ten years since it was published. I know there was a recent email tip featuring it. Over at a NC based forum, you could search and find it.

[Mark Gibney]

Lee, what you say about Cosman's design working better if the far end of the tube was open to allow more air flow makes sense. Thanks for that insight.
Andrew, thanks for that indepth explanation of the differences between shopvacs and dust collectors, and the link to the test. I suppose few shopvacs are designed to be used for a long period without a break.
Some ingenious solutions here. I'm happy there are workable solutions I can just copy.

[Randall J Cox]

On my old 10" delta, I used the white angled 4" plastic piece (with the square mounting edges) shown in an earlier picture. I got that up as close as I could get it and made brackets to attach to existing bolts on the bottom of the table. I made the metal attachment brackets angled to directly target where I wanted to vacuum sawdust by looking up into it. Then I slid a 4" OD PVC pipe up into it (snug fit) and trimmed the edges until it pretty much was right up to the cutting edge of the blade right after coming through the table AND under the lower guides. I then put some small sheet metal screws through the white plastic piece into the 4" pvc to hold it in place. The pvc piece was cut to protrude out the back end of the white piece by only an inch or two. Then I then attached about 4 feet of 4" flex dust collection hose to it and then to
a sheet metal 4" to 5" reducer (Lowes) which then connected to my system. Although almost all my ductwork is 5" with a 2hp Powermatic dust collection system (small compact shop), even with necking down to 4", I still have lots of suction. I think targeting the suction is the key, getting it as close as you can to the source of the sawdust. Mine works great. Good luck. Randy PS That is the only collection point on my BS.