Can you have too much Dust Collector?

[Dan Case LR]

This question may have been fielded here before, and if so I apologize for the duplicate--but I couldn't find it in the search engine.

Is it possible (in practical terms) to have too much dust collector for a given shop? Is there a downside to oversizing?

My worst-case machine is the table saw--with both top and bottom collection active, I need to move 1135 cfm at 4.7" SP. I have two cyclones on my short list that will just make this requirement, the Penn State 1425S and Oneida's V3000. I have a natural tendency to overbuild (I've never heard anyone complain about something being built too sturdy!) Just looking at pricing and real cost at this point, but would a 5 HP cyclone deliver better performance? Is it too big? Too powerful for the need? I keep thinking about the guy I once knew that loved putting huge motors in small cars but often had structural problems as a result--too much torque for the structure to handle.

What do you think--is thee such a thing as too much dust collector for a given shop?

Thanks!

D.

[Ole Anderson]

3 hp to 5 hp, probably not, but there is a point of diminishing returns, 10 hp would just be a waste for a one man shop, usually an efficient 3 hp is plenty unless you insist on keeping several blast gates open at a time or you have very long runs and you are using 6" pipe where you need the extra static pressure to overcome friction losses. My concern is one of energy use, a 5 hp motor isn't cheap to run. How are you plumbing your TS such that you need 1135 cfm? 600-800 Is usually plenty with a top and bottom duct system, even 6" bottom and 4" top, which IMHP is a bit of overkill. But that is me. By the way, if you are really going to be moving 1135 cfm you should be thinking 7" or 8" duct.

[Dan Case LR]

"Overkill is very useful if you want to make sure it's dead."

I modified my 3HP cabinet saw (Grizzly G1019) for a 6" port when I put in my first duct system for my woefully underpowered current DC. I added a Shark Guard with a 4" port some time after that. My 1135 cfm number is based on a worst-case--350 for for the 4" and 785 for the 6". Those numbers may be a little high, but I'd rather err on that side than underbuild. If there's one thing I've learned about grabbing dust from that saw, it's that youcan never move too much air through it.

After wrestling over options, I've decided to go with metal duct (probably snaplock unless I trip over a stash of spiral pipe and fittings in a dark corner of someone's warehouse that they want to dispose of quickly), with 7" mains and 6" drops. To manage the cost of ductwork I plan to light up the new cyclone in phases so I don't have to eat it all at once. For part of that transition I'll keep the old DC online (the cyclone's going in a different spot) and for part of it I'll connect a portion of the existing PVC to the new cyclone. I'm rearranging at the same time, so the Table Saw and Jointer (both relocating) will get the first taste of the new system.

I'm still waffling between three or four options, and am now at the "comparing dollars and value" stage of my quest. After looking at my options on equal ground (for example one option has a silencer, one does not, so I add the price of a silencer to keep the playing field level), I noticed that if I go with the Oneida V3000, I can upgrade to 5 HP (V5000) for only $165. Now I'm balancing the additional electric power cost. It's interesting that one of my options, a 3.5 HP from Penn State, consumes as much power (same current rating) as the 5HP Oneida. Love that efficient Chinese technology.

And Oneida has a half-price shipping deal ($125 instead of $250) which helps close the gap between choices too.


So many decisions, so few brain cells.

D.

[Tom Hartranft]

Quick look at Oneida V3000 vs V5000 specs shows couple of somewhat negative operating differences for the V5000:
a. Electrical: V5000 rated at 19.5 amps ; V3000 rated at 13 amps. So, a 20 amp circuit would handle the V3000 while the V5000 would likely require a 30 amp circuit.
b. Noise: V3000 rated at 75 dBA at 10 ft; V5000 rated at 81 dBA at 10 ft. So, V5000 generates 6 dBA more sound power ... which is about 4 times more sound power than the V3000.
c. Filtration: The filter is rated the same for both the V3000 and the V5000. So, although airflow is rated higher for the V5000, the filtration media and surface area will be the same as the V3000.

[Brian Henderson]

I don't think you can get so much dust collection that it becomes dangerous or damaging, unless you're using a jet engine and suck your entire shop into the Twilight Zone, but there is certainly a point of diminishing returns where having a ton of power gives you no better results than somewhat less power.

[Andy Booth]

Have you looked at clearvuecyclones.com who build a descendant of Bill Pentz's cyclone? (http://billpentz.com/woodworking/cyclone/)
I found many of his arguments persuasive.

Andy

[Michael W. Clark]

You obviously have to be able to power the larger motor, deal with the noise, and handle the increased filtered air or make-up air as others have stated.

A couple of other points;
1. To see the full benefit, you need to size the duct and connection points accordingly. If you use 6" duct on a 5HP collector, you are likely choking the flow in a 2-car garage shop. If you had long runs requiring a lot of SP, the the 5HP and 6" duct may be a good fit.
2. Only a couple of operations come to mind where you could have too much flow. One is the TS overarm guard where you could pick up pieces (especially small ones) that would be better left on the table. The other may be a router table. I am not sure, but it may be possible to have so much SP that the board is harder to push past the bit and opening when using under table DC?

Other than these cases, more is probably better. A 5hp DC is a good size for a home shop, but it is still a baby in the DC world.

Mike

[Jim Andrew]

My cyclone sucks pieces up off the top of my table saw and it is only 2hp. I improved it by going with an oversize filter.