That would be interesting! This all makes me wonder why the Jet DC and all of my machines have 4 inch ports. Looks like I have some modifying to do.Originally Posted by Curt Harms
Member
That would be interesting! This all makes me wonder why the Jet DC and all of my machines have 4 inch ports. Looks like I have some modifying to do.
[OP]
Member
OK, here's a question.
If I were to make a new hood for my RAS and build in a 6" port, I could see how that will pull plenty of volume to move the dust through the larger pipe since the hood is wide open.
But on something like a TS, if I put in a 6" port, will there be enough access to air to pull the necessary CFM? In other words, would it be too choked off? Ultimately I know having the 2 4" would be better (one being over head), but in the meantime if I hook up a 6" and it can't draw enough volume, it won't be able to move along in the duct...if that's the case, I would think I'd be better off staying with 4" untill I get around to making an overhead hood.
Member
When Lance added a second 4" line, he essentially doubled the air flow. It shows that the restriction is a 4" hole anywhere along the duct including the equipment port. I got a similar improvement by replacing all 4" ducts and ports with 6" diameter. It was enough that a 1.5 Hp Jet blower became adequate. The 4" port acts like a half closed valve on a big diameter water line. The only way to move more water is to add pressure (bigger DC) or a bigger port (4" -> 6").
I do not find dust and chips dropping out in a 6" riser, even with my dinky blower.
[OP]
Member
So there's enough open spots on the saw to feed the additional air volume needed for the 6"? I thought that there would be, but me thinking and someone else knowing is...well the reason I ask all the questions I do!
Thanks for sharing your experience!
Contributor
I have a G1023. I had to stuff some foam between the table and cabinet and put magnetic sign material over the opening for the height adjustment wheel in order to get decent velocity thru the blade slot. At least on my saw air starvation was not an issue.
HTH
Curt
[OP]
Member
Running 4" or 6"?
Moderator
I should do that on my Griz 1023Z but I'm too lazy to improve the DC on it right now.
Most TS are plenty leaky so there won't be any air starvation...no way!
Moderator
Well, lets' see...4" duct can handle about a maximum of 300-350 CFM...you just can't fit any more air in it physically at the given velocity. 6" duct can handle 600-800 CFM since the area is much larger. That should help you make your decision!
--
The most expensive tool is the one you buy "cheaply" and often...
Moderator
I don't think there is any point in "grounding" PVC. It is quite difficult to do a good job grounding it so why even bother? No hobbyist shop is going to ignite sawdust...just won't happen.
Guest
Did you check the Bill Penz dust collection web page. It's excellent.
In short, run 6" as close as you possibly can to the tool.
The book probably said to use 4" drops off the main line because most people aren't going to go through the trouble of changing the size of their dust ports on their machines.
For a tablesaw, the ideal thing (at least in someone's opinion) is to split the 6" line into a 5" line going to the bottom of the cabinet, and then have a 4" going to the blade guard collection (I use a shark guard).
I have a dual drum sander with 2 dust ports. I ended up making them both 5", against recommendations.. but since the runs of 5" are very short (maybe 3 feet), I don't think it's a problem.. It seems to work ok.. but in general, they say to split a 6" to a 5" and a 4".. that's supposed to be the best balance.
Member
Walt,
When I first installed my DC I found I had chips and shavings still int the DC ducting (el-cheapo corrugated 4" flex stuff) after letting the DC run for a minute after shutting off the planer or jointer. I found I got better results (ie no leftovers in the ducting) when using my planer & jointer if I actually left an additional blast gate partially open, meaning I was starving the DC for airflow. Since going to a 6" main, I can use just the blast gate hooked to the jointer or planer and keep the chips-shavings moving (no leftovers).
Installing the PVC is cheap and very easy. I'd highly recommend doing it the first time.
Greg
Member
Hi again Walt,
You can remove the factory installed "wye" piece on the inlet port on your DC to find it's 6".
Greg
Guest
Marketing. Woodworking machines should have DC ports, DC ports are 4", so lets slap a 4" port on them. That will work ok for chips but not for dust. If you want a machine with reasonable DC capabilities you need to look at machines designed for a more industrial environment where dust exposure limits are regulated. That's where you'll see the 5", 6" and larger ports on machines. Eventually that will make it's way down to our machines.
Most small units (like mine) have 4" ports. Larger units have 5" - 8" and generally make the concession of including an adapter to multiple 4" ports at the machine.
A recent review took a variety of machines and tested them. Some of the 4" machines that ran larger motors were tested with 6" duct and actually improved on short runs (interesting for the test but not long enough for most shops). None of the 4" machines were as good as even the smallest 6" machine but there is a lot of engineering involved outside of hose size ;-)
My Delta does fine with one machine at a time. It starts to suffer running the overarm and the cabinet on the TS but I adjust with the blast gates. A decent sized cyclone is somewhere down the road for me (I hope).
"A hen is only an egg's way of making another egg".
– Samuel Butler
[OP]
Member
Yes, I did read quite a bit of it...and I'd agree with your summed up description. Seems the major point he was making that in his opinion, he doesn't think 4" gets the job done, so 6" should be used.
I'm pretty sure I'm going to go with 6". Just seems to me like that makes the most sense for my set up.
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