Miter Saw Dedicated Vac

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Forum topic by James posted 01-25-2018 11:12 PM 1718 views 1 time favorited 21 replies Add to Favorites Watch
View James's profile


142 posts in 2559 days

01-25-2018 11:12 PM

Topic tags/keywords: dust collection vacuum

So I’m going to set up a small shop vac in one of the cabinets my miter saw station is built on. The vac will never move. I ordered a amperage draw switch for it and my question is this…

How much power(HP) is necessary to suck up a decent amount of dust? I realize that miter saw dust collection is the least effective circumstance where you would collect it. I’m not building a hood or anything, I just want a majority (51% or better) collected. I sell tools so Shop Vac is the brand I’ll use. My two options are a 2HP/1.5 gal or a 4.5HP/4 gal vac. I realize 4.5 is more than 2 but it will be taking up three times the space and less important, the smaller vac is half the cost.


-- James - Semper Fi

21 replies so far

View Loren's profile


10477 posts in 4420 days

#1 posted 01-25-2018 11:31 PM

I think you’ll be underwhelmed with the
performance of either. With one port
on the saw I doubt you’ll see a big bump
in dust collected by going to the larger
vacuum. Either is only going to catch the
dust the saw is shooting right out the port

View Alex Lane's profile

Alex Lane

574 posts in 4662 days

#2 posted 01-26-2018 12:57 AM

I see Loren’s point. A big rectangular dust hood behind the saw connected to a portable dust collector with a 4” hose might catch much more but can still remain relatively compact. Maybe there’s a way to attach a little rubber flap behind the saw blade that rests on top of the wood being cut and ramps much more of the dust into the port on the saw. I think the festool miter saw has something like this.

-- Alex...builder of wooden wings for vintage sport biplanes...I'm your wingman :)

View SweetTea's profile


477 posts in 1432 days

#3 posted 01-26-2018 01:21 PM

You are never going to get the results that you desire with a shop vac. I was in a similar situation and found a perfect solution. What I did was buy a Big Gulp Dust Hood from Rockler, and a clamp from them as well so that I can mount the hood directly behind the miter saw, positioned very close to the back of the saw. I then went out and purchased a 2HP Harbor Freight dust collector which cost me $169 with a coupon. Say what you want about Harbor Freight, but their dust collector is great, and I own several. Now I have excellent dust collection at my miter station. The entire setup was $169 for the 2HP dust collector, $30 for the Big Gulp Dust Hood and $20 for the clamp plus $10 for shipping. Total cost was approx $230. This setup would be perfect for you, and would be soooo much better than a Shop Vac.

View Carl10's profile


115 posts in 1229 days

#4 posted 01-26-2018 02:48 PM

Ditto to all the above responses. The best way I have seen someone get more dust with a shopvac on a MS is to build a custom shroud/pickup around the blade exhaust. If you look on youtube and search for miter saw dust collection you will get several ideas. Of course they are all saw dependent. The only way any suction will be effective on a MS is to narrow the focus of the flow. With the little air from a vac, the most success has been to narrow that flow around the blade output.

BTW looking at the CFM of the 2 units you describe it appears the larger unit has almost 3x the airflow. Your best results, especially if the vac is stored below the saw will be to have a separator like a Dust Deputy to keep the filter clean. I could not imagine using the smaller vac without a separator and a large bin next to my MS. That little vac would clog up so fast and become useless in minutes. Just make space for a removable bin under the separator next to the vac for the significant amount of dust you will be collecting. The surface area of a vac filter is so small they cake up really fast and performance drops fast.

Hope this helps. Let us know what you do.


View MinnesotaSteve's profile


56 posts in 1663 days

#5 posted 01-26-2018 03:13 PM

If you just want to get 50%, you’ll be fine with a shopvac. On my Makita 10” non-slider I get about 80% with a 3hp shopvac using a 1.5” hose. I think that non-slider is best case as the dust port is straight in back, whereas sliders tend to be more problematic.

I would suggest the 4.5hp shopvac, I don’t think the smaller one would be enough, and it’d fill up really easily.

Worst is you try it and it doesn’t work, then you look for further solutions.

View JRsgarage's profile


367 posts in 1281 days

#6 posted 01-26-2018 05:08 PM

i’ve been looking at a Rousseau 500 for my saw but mine is not stationary. i think something like this, as mentioned above, will benefit more than the difference in hp of those shop vacs

-- “Facts don't care about your feelings.” ..., Ben Shapiro

View Andybb's profile


2762 posts in 1376 days

#7 posted 01-26-2018 06:00 PM

My miter saw has it’s own dedicated vac only because I don’t have blast gates and I use it all of the time. It’s a cheapie Lowes vac that sits on top of a 5 gal bucket so a shop vac would do at least as well and is hooked up to one of these.

This setup has virtually zero cost to make and works as well as anything I’ve seen.

-- Andy - Seattle USA

View James's profile


142 posts in 2559 days

#8 posted 01-26-2018 07:01 PM

I like this concept. That’s the switch I ordered. And the vac is really only there to get all the stuff that already shoots out of the back of the saw. It’s not a slider so lots of dust should get sucked up. I usually open up the garage after projects and use the leaf blower to get it all out. Bulk collection is all I’m worried about.

My miter saw has it s own dedicated vac only because I don t have blast gates and I use it all of the time. It s a cheapie Lowes vac that sits on top of a 5 gal bucket so a shop vac would do at least as well and is hooked up to one of these.

This setup has virtually zero cost to make and works as well as anything I ve seen.

- Andybb

-- James - Semper Fi

View Andybb's profile


2762 posts in 1376 days

#9 posted 01-27-2018 12:47 AM

That should work well for you. I use the leaf blower solution also. Except for the miter saw, my main DC system is based on a big ass shop vac inside of a plywood cabinet which makes it almost silent with a DIY cyclone and a long ass hose that I just swap around depending on the tool I’m using, . All of the other tools go into a long power strip which plugs into this switch which gives me the ability to turn the vac on independently for clean up etc. Very handy. The cabinet is on wheels and doubles as a stand for my drill press, scroll saw and grinder.

-- Andy - Seattle USA

View mtnwalton's profile


77 posts in 1798 days

#10 posted 01-27-2018 04:22 AM

I’ve used this setup on my Bosch Glide with great results, 95% collected when not cutting aggressively.

View John_'s profile


251 posts in 2478 days

#11 posted 01-27-2018 07:57 AM

I have the 12” Bosch Glide and the one of the Bosch Vacs dedicated to it and I would say it easily gets 50% of the dust. I modded the dust chute on the saw similar to what Andy did in his pic.

And my 36v Makita Blower will easily take care of any dust that vac didn’t get

View sawdustdad's profile


379 posts in 1657 days

#12 posted 01-27-2018 01:41 PM

I like the Rigid (Home Depot) shop vacs. I have one of their smaller ones (5 gallon?) hooked up to my SCMS. I’d say it get 50% or more of the dust.

-- Murphy's Carpentry Corollary #3: Half of all boards cut to a specific length will be too short.

View Robert's profile


3742 posts in 2253 days

#13 posted 01-27-2018 03:55 PM

I’ve had 3 different DC setups over the years. I think the best way to collect some machines like sanders, miter saws and routers is to have a dedicated vacc. You can pick up shop vacs quite cheaply at flea markets and garage sales so it is very cost effective to have several dedicated vacs.

I have to disagree with some of the comments in that shop vacs give me very adequate collection on both my miter saw, sanders and router. No doubt the miter saw is the hardest to collect, but a through-the fence/under the table type system works really well. Keep in mind the efficiency of collection depends somewhat on the saw design but I think you should be more than able to achieve 75%.

Regarding the switch boxes, be aware if you run a large vac on the same circuit as the saw, you may have an issue with breaker tripping due to start up amp draw the saw generates. This happens to me so I have to plug the vac into an outlet on a diff circuit.

-- Everything is a prototype thats why its one of a kind!!

View SweetTea's profile


477 posts in 1432 days

#14 posted 01-27-2018 04:25 PM

Why even mess with a shop vac when you can get a good 2HP Harbor Freight dust collector for around the same price, if not less than a shop vac + dust depuity? The HF unit is $199 and with a 20% off coupon it comes down to $160. Assuming that you have the space, that would give you much better performance than a shop vac, plus, since it has two input ports, you could run one hose to your miter saw station and the other side could feed to a table saw, router table, planer, jointer or any other tools that you might have.

View Andybb's profile


2762 posts in 1376 days

#15 posted 01-28-2018 05:50 AM

Why even mess with a shop vac when you can get a good 2HP Harbor Freight dust collector for around the same price, Assuming that you have the space,
- SweetTea

As you said, space is the issue for me. I still need to get 2 cars in my garage occasionally, like when it snows, so on “my side” everything is on wheels and lines the walls. My shop vac is inside of this cabinet which has 3 other tools on top of it and the cyclone is mounted high on the wall. I’m happy with the performance. I keep a bag in the shopvac to catch the overflow and any fine dust from the cyclone. Only need to empty it a few times a year.

-- Andy - Seattle USA

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