Adapt shop vac hose down for long run

[Doug Hobkirk]

I read and believe that a 6" DC duct is vastly better than a 4" duct. Which makes me curious about the best solution for my shop vac situation.

I want to use my 16G Craftsman vac on my circular saw, power hand planer, & router. The hose is 2 1/4" OD (2 1/16" ID). I await a Bosch "Dust Chute" to measure it exactly. Then I will match the fittings on my other two tools. Let's say it's 1 1/2" OD.

I can find an adapter for 2 1/4" to 1 1/2". But should it be at the vac end or close to the tool end? And I imagine the question becomes even more relevant if the tool fitting is 1 1/4" (?).

(1) I can run 1 1/2" PVC to the saw station, or a central vac 1.5" hose (pretty smooth inside), or a very smooth 1.5" industrial suction hose. OR (2) I could run multiple Craftsman hoses to the work station and put an adapter there and use a much shorter 1 1/2" hose to the tool. OR (3) I could buy a $450 shop vac that already has the correct size hose.

I can't afford option 3! Is there a significant performance advantage to option (1) or (2) over the other?

[jason lambert]

It will not really work the main problem is most shop vacs produce about 200-400 cfm (measure of air volume moved). By increasing the size hose you are going to reduce the amount of material it can move. Dust collectors produce 900-1400 cfm's, 3-4 times the amount of air movement. I have to use a extra large hose and cut slow on my plainer to allow my vac to keep up, also my router table I now am using 2 vacs hooked up to it to get adequate collection.

I would really suggest getting a small dust collector maybe a small portable one. Or even a the harbor freight one is pretty good for $200 if you change the bag there are lots of threads on this.

I am in the same boat as you I have been trying to make shop vacs work I now have 3 fest tool vacs and a fine vac around the shop. Working on a dust collector now....

[Mike Spanbauer]

Jason, while you are correct re: the CFM there is a significant omission from that comparison. Vacuum is measured (the suck portion) by the ability to lift a colum of water to a certain height. I've a monster cyclone which only pulls 13.5" of water up that column, however my festool CT33 pulls 90" of water. In non-technical terms, it sucks harder.

Performance is a combination of both the suction power and the volume of air moved. My cyclone pulls 1500cfm @ 10"+ vs. the more simple 134CFM that the festool pulls.

I probably muddied the answer to the OP's question though, but in my understanding you want to neck down the vacuum lines as close to the tool as possible (which will achieve the least amount of loss.) However, in few cases can a dust collector be replaced by a vacuum or vice versa.

Mike

[Doug Hobkirk]

Thanks Jason & Mike -

I am puzzled however because I have read (somewhere) that small tools need suck, not CFM. That a DC does a lousy job on a hand router or circular saw. I actually have a 2HP DC that I haven't hooked up yet, but I expected to use that for the planer, table saw, and jointer.

My gut feel is that you are correct about running the 2" as close as possible to the 1 1/4" tool. And somebody in this forum has an amazing DC system using a shop vac, 1.25" PVC ducting, runs up to 40'.

How could I get confused? I guess I'll have to experiment - I just realized I can use the house central vac hose for testing.

[glenn bradley]

I am puzzled however because I have read (somewhere) that small tools need suck, not CFM. That a DC does a lousy job on a hand router or circular saw.

Not sure what the science says but I can tell you my experience. My 16gal vac works much better on hand tools and even on the CMS than the DC. Seems like the higher velocity catches that fast moving stuff better in practice.

There may be some math that says otherwise but in actual use the vac does a better job, no question. I run a 25 foot 2-1/2" hose that reduces to a 1-1/4" for the last four feet. This works so well on my ROS that I actually have to use 'bleeder' to reduce the suction or it slows my Bosch sanders down.

[Doug Hobkirk]

Glen - thanks, right on point - I was hoping to hear about real-world experience. [Good quote - I could use it just by changing 50 to 60]

[Randal Stevenson]

I want to use my 16G Craftsman vac on my circular saw, power hand planer, & router. The hose is 2 1/4" OD (2 1/16" ID). I await a Bosch "Dust Chute" to measure it exactly. Then I will match the fittings on my other two tools. Let's say it's 1 1/2" OD.



The Bosch dust chute has an adapter to make it fit a shop vac hose. Without it, I believe it is metric (35mm if I remember).

[Greg Hines, MD]

I would just comment that regardless of the fittings, replacing your original paper filter with a CleanStream filter will dramatically decrease the dust that escapes your shop vac. I am also going to replace the standard hose with one of the polyethylene hoses that is smooth on the inside to improve its efficiency.

Doc

[Bill White]

I have a short section (18" +-) that I hook to the ROS or CS, then the 2 1/2" to the vac. Works well for me.
I do wonder some time if we are over-thinking the quest for "perfect" dust collection, then we take off the blade guards on our saws.
Bill

[rob forham]

Also consider a mini-cyclone. I just installed one between my rigid 6 Hp 16 gallon vac and circ saw / router / ROS / belt sander. I added a cleanstream filter to the vac.

You can make a plastic dust shield ( soda bottle, packaging you need to cut open to get at the product you just purchased, etc. ) for your circ saw and use double sided tape to mount the shield.

I am amazed how clean my garage is with this setup. almost everything is captured by the cyclone and the cleanstream filters particles to 0.3 microns.

[Doug Hobkirk]

...You can make a plastic dust shield ( soda bottle, packaging you need to cut open to get at the product you just purchased, etc. ) for your circ saw and use double sided tape to mount the shield....

I certainly agree, Rob. 1 hour ago I received a Hitachi Pro saw that I ordered yesterday from Dino at Eurekazone with the Bosch Dust Chute and the dust shield already installed. Sweet!

Alas, I am forced by other duties to delay making sawdust. And it will be a couple of more days before I get to experiment with the vacuum.

[Paul Greathouse]

[quote=Doug Hobkirk;781358]Thanks Jason & Mike -

I am puzzled however because I have read (somewhere) that small tools need suck, not CFM. That a DC does a lousy job on a hand router or circular saw. I actually have a 2HP DC that I haven't hooked up yet, but I expected to use that for the planer, table saw, and jointer.

My gut feel is that you are correct about running the 2" as close as possible to the 1 1/4" tool. And somebody in this forum has an amazing DC system using a shop vac, 1.25" PVC ducting, runs up to 40'.


Doug, you may be referring to my setup, I have the Shop-Vac Professional with the stainless tank and I'm running through at least 40' of 1.25" PVC through several fittings and PVC valves. Besides the length of run, the dust is lifted about 8' straight up from my cutting table to the truss area of my shop before it continues over to the Rockler bucket lid cyclone and shop vac. I also have the Hepa filter in the vac.

This setup works great for my Hilti 267E circular saw and my Dewalt compound miter saw but I did stop up the 1.25" pipe when I tried to route dados with my dewalt router attached. Now when I want to route I hook the router up straight to the bucket lid cyclone instead of going through the 40' run of pipe. The chips coming off of the router were just too much for the pvc pipe bends but works just fine going straight to the cyclone. I have some pictures of the setup in one of my old posts.

[James Suzda]

I'm going to throw my opinion into the mix here. If you think about a central vac system in a house they run 2 or 2 1/2 inch pipe all over the house then neck it down much smaller at the wall connectors to which a small hose is connected. So, thinking along those lines, I'd say run the larger hose and then reduce it down right at the tool.