Screaming Dust Collection Hose!?

[Mike Cyros]

Hi Everyone,

Typically, I run 4 inch hose to my dust collector, but for some tools like my smaller 12" bandsaw and my miter saw, I run 2 1/2" hose with a 2.5" -> 4" adapter at the dust collector. Whenever I use the 2 1/2" setup, when the dust collector is up to speed, it starts to generate a piercing whistling sound (I imagine that this is a whorling vortex created inside the clear flexible collection hose). Has anyone had this experience, and more importantly, and suggestions as to how to stop it (besides not using 2 1/2" hose?).

Thanks!

...mike

[Frank Hagan]

You can get some very strange harmonics with air flowing through things. Try little modifications ... pinch the hose a bit to see if it changes the noise, try running the DC with the 2 1/2" hose detached from the adapter, etc. Very often you are in a "sweet spot" and a minor change to the backpressure in the hose will solve the problem. (My experience isn't with a DC, but with a large commercial boiler that our engineers finally corrected, but at a lot of cost and trouble. The fix was a relatively simple baffle.)

If removing the small hose solves the noise, you might try using a tee, with a blast gate that you can partially open to help satisfy the air demand of the DC, just ahead of the adapter down to 2 1/2".

[Jim Becker]

It's best to reduce at the tool, not at the collector, but you will still have a nasty noise level with such a small port. Franks suggestion to reduce SP by opening up a gate on a wye is also a good thought...it will not materially reduce "performance" on the small port since it can't move much air there anyway and will reduce noise a bit since the velocity will drop in the small port. The air "rushing" through the small opening is what is causing the howling. (If it were a very small hole, it would be a whistle!)

[Mike Cyros]

Thanks for your suggestions! Letting a bit of air in makes a huge difference in the sound, and doesn't seem to impact the performance that much. Thanks again!

...mike

[James Mudler]

My blade guard on my TS produces a loud noise and I found drilling a 1/4" hole on the sides of the guard elminated the problem.

[Frank Hagan]

Its really astounding how little you have to do sometimes to change the noise. I've always been surprised by that, but I suppose its because I really don't understand the underlying physics ... I think it was Arthur C. Clarke that said something like any modern technology is indistinguishable from "magic" to those ignorant of the technology.

[kevin tompsett]

Add a 4” to 2x 2.5” hose at the tool. Place second hose somewhere useful