HF Dust Collector Help for Head Porting.

[Rich Pritchard]

Nice work Chad, very innovative. I was wondering if a sturdy grate style floor, (ala' barbQ grill style) rather than a flat sheet w/ holes might be more efficient. Also, painting the wood part of the chute w/ enamel might help keep chips and dust from sticking to it. Anyway, I'm impressed.

[Chad Speier]

I thought of that Rich. Grizzly has a bench like that. While testing, I found a piece of peg board with many hole was OK, but it seemed to be lacking on suck. when I started reducing the holes, I was getting what I wanted. But it was loud. This now will flat pull a chip into the hole, it's actually amazing. I was getting some whistle off it but I fixed that. It's no different that calibrating a flow bench. A hole like these need a taper on the bottom side. A calibration plate has a sharp edge on one side. Sharp edge goes down when pulling, edge goes up when pushing for calibration purposes. I basically made the hole sharp edged and the whistle and flow through the hole increased.

I could get really cool and use my pitot tube and see how much cfm a hole is pulling.

Well, I went ahead and did it. This is the formula I used.

CFM= (FPS x CSA) / 2.4

81.08 fps
.933 hole= .68 sq. inches

81.08 fps x .68= 55.13/2.4
22.98 CFM

Now the question, is that good or bad?? I have 10 holes total.

[Chad Speier]

Hey Guys, I just wanted to bring this thead back up and report that I have been using this set-up for the last 9 months. It has worked flawless! No dust in the shop, pulls cartridge roll dust out of the air.

That Thein lid is the crap! This system is even more remarkable in person.

Thanks Again for all the help!!