Why drops?

[Chris Holder]

We all know there is a huge debate around 4" vs 6" pipe from machine to DC unit. What I am curious about is whether anyone else out there pipes DC directly all the way to their machines without the use of flex hose?

Flex hose causes so much pressure loss, that I thought it would be better not to use it at all. Obviously, this is not an option if you have to move machines around, but if stations are fixed, it can definitely work (or at least it does for me).

[Jim Becker]

Yes, there are some machines the lend themselves to direct connection, such as stationary drum sanders, some planers, jointers, table saws, etc. (Of course, they are still "drops" in the sense of being branches off the main... :) ) But in other cases, short flex connections are still required. That's the case with both my J/P combo and even my sliding table saw. (The only two "truly" stationary tools in my shop) In the case of the J/P, the connection needs to be switched to different hoods during conversion. In the case of the slider, the blade shroud connection moves and the dust collection connection also needs to move with it.

But you are absolutely correct, a solid duct connection is less restrictive when done well.

[Ken Ganshirt]

There's also the issue of the final connection to the tool. It's often difficult or impossible to create a large enough opening to get to the size of the main. So there has to be a reducer at some point in the run, preferably right at the tool.

...ken...

[Jim Becker]

Ken, even that can be handled with direct ductwork to the tool. You can get pretty much any reducer combination you need to adapt from the drop size to the port size. You pretty much can direct duct to any tool outside of where the actual connection must be flexible to function as long as the tool is truly stationary in the shop.

[Jim O'Dell]

I keep flex as short as possible. The piece on my TS stretched out is about 12". The piece on my BS is only about 5". Just enough to keep the vibrations of the machine out of the pipe, and make the connections easier to do. Jim.

[Chris Holder]

That's what I thought. I understand that there are obviously some applications where flex hose is necessary, but in our age of underpowered dust collectors, the average WWer in his garage may not have the money nor space for a cyclone. I use a 2 hp delta with 6" SWD piped directly to the units (I size down at the machine). This seems to provide sufficient suction with blast gates as my longest run is only about 10' with 3 90 degree turns.

[Chris Padilla]

Everything in my shop is mobile so flex makes life easier. Take the hard 6" as far as you can and make your compromises right at the end.

[Joe Chritz]

I have a couple that could be plumbed directly but using a couple feet of flex makes like much easier.

The flow savings over 2 or 3 feet isn't so much as to make a huge difference. Especially if you have to use a couple 90's to do the connection. Make that run 15' long and it is a big difference.

As long as the machine isn't mobile and the connection is easy to make there is no downside to directly plumbing it.

Joe

[David Giles]

I agree. Unless the machines need to be mobile, why not hard pipe everything? Even though my work area is only 12x26 with a 2" out of level floor, I found it easier to set the saw and jointer in a permanent position. Cutting a larger hole in each machine was easier than trying to figure out how to swage down or match metal to PVC fittings. It can be as simple as cutting a 6" hole and sticking in the PVC pipe. The air flow increases so much that a little leakage doesn't matter. Great approach for getting the most out of those 1.5 HP dust collectors.

[Jerry Pittman]

Chris,
Use as much solid pipe as you possible can. As has been said before, some machines are very difficul to connect to the system without a short piece of flex but keep it to a bare minimum. Flex can't flow air and chips/dust as freely as smooth pipe. I run trunk line and drops as close to each machine as I can and then finsh with flex, usually 2 feet or less. I use 4" thin wall PVC for everything but my longest run is 25 feet or so. I keep the big chip producers, planer and jointer, closest to the DC. I know that using larger diameter for the trunk lines and reducing the diameter as you get farther away from the source is the 'proper' way but 4" throughout is working pretty darn well. I also have only one or two gates valve open at a time unless I forget.
Jerry