LumberJocks

DC 6 or 4 inch mains

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by Paul C. posted 12-28-2010 09:33 AM 848 views 0 times favorited 7 replies Add to Favorites Watch
View Paul C.'s profile

Paul C.

154 posts in 2710 days


12-28-2010 09:33 AM

Topic tags/keywords: dust collection duct

I know this has been beaten to death, but not by me! I have a 1.5 hp Steel city DC rated at a nominal 1200 CFM, hooked to all my equipment with 4 in PVC. The runs to my tablesaw, planer and jointer are very short and straight (less than 8 ft,) all told. My question is this: would i benefit from 6 in duct to each of these machines? I suspect that the dc is not powerful enough to keep the fine dust “entrained.” My duct then runs up over my ceiling to smaller machines: drill press, router table, which i gather from with a 2.5 in. duct.

Am I wrong? I really want to do this right, and I can’t use any 220, or I would have bought a Clearview.


7 replies so far

View Paul C.'s profile

Paul C.

154 posts in 2710 days


#1 posted 12-28-2010 06:02 PM

Anyone?

View Gregn's profile

Gregn

1642 posts in 2448 days


#2 posted 12-28-2010 07:11 PM

I would stay with the 4” myself due to the size of your DC.

-- I don't make mistakes, I have great learning lessons, Greg

View ClayandNancy's profile

ClayandNancy

511 posts in 2480 days


#3 posted 12-28-2010 07:17 PM

I’ve been researching this same topic for awhile now and I believe the info leads to at least a 2 hp DC to be able to keep air velocity and cfm at a high enough level to keep the dust from dropping out of the air stream in a 6” pipe. Some will say that they don’t have any problem, I don’t know how well theirs works. A lot depends on length of runs and the number of turns.

View crank49's profile

crank49

3981 posts in 2435 days


#4 posted 12-28-2010 07:48 PM

What is the diameter of your fan inlet? There is no need to make the pipe any larger than that.

There is no way a 1.5 hp collector can move 1200 CFM with any amount of useful pressure. Manufacturers specify “pie in the sky” capacity numbers all the time that don’t mean squat. Just like the Ridgid shop vac with 6.5HP proudly displayed on their box. Yeah, right, and it runs on a 120v outlet, it’s amazing. Back here on the real world a 1.5 hp fan might actually move 450 to 500 CFM at 9” to 10” static pressure. That will give you about 2300 FPM velocity in a 6” pipe and anything less than about 3000 FPM will lead to plugging problems.

I would not go any larger than 5”. And, 5” is hard to find and expensive, so that leaves 4” as your best alternative. You could probably run a 4” and a 2.5” both open at the same time with a balancing damper in the system. I have that setup on my 2hp DC and it works well.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

View Paul C.'s profile

Paul C.

154 posts in 2710 days


#5 posted 12-29-2010 01:08 AM

My fan inlet is 6” but there is a 4” restrictor in the opening. I’m not convinced that removing it is good idea. I get pretty good flow but have no way of measuring it objectively. I am concerned with fine dust.

View crank49's profile

crank49

3981 posts in 2435 days


#6 posted 12-29-2010 02:26 AM

The restrictor is probably there to keep the motor from overloading. Contrary to what many people think, choking a fan intake is not what overloads it; it’s just the opposite.That 4” orafice is saying you need to stick with 4” pipe.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

View Paul C.'s profile

Paul C.

154 posts in 2710 days


#7 posted 12-29-2010 02:50 AM

I was pretty sure that was the case. bummer. I have limited options with only 110V. I must admit, I have pretty good clearance everywhere but the tablesaw. I have been reading too much Bill Pentz (is that possible?) and have my butt in a bit of a knot about entraining fine dust. I worry about it ‘cause my 4 year old loves the shop, but won’t wear a mask. She has autism, so its a little tougher to convince her without a total meltdown.

I wish i had the money, space, and power for a clearview…..

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com