Evaluating Small Dust Collector Equipment

      Low-end dust-collection equipment is designed for the hobby shop, and the ratings don't mean much. But they can still work for a small professional application. Here's a detailed look at how to set up a budget DC for decent performance. August 14, 2007

Question
I am thinking of buying a dust collector before the end of this year. I'll use it for my miter saw and router table, so all I need is a small unit. I've been looking at some models and found most of them have similar specs, from Delta 50-760 for $289, Jet DC 1100A for $349, and JDS 14040 for $299. I think JDS is better because with the same money I can get the unit that collects down to 1 micron and 1250cfm.

My main concern is the customer service and accessories availability. Some reviewer at Amazon had bad experience with Delta customer service. Have any of you have experience with JDS customer service?

Forum Responses
(Dust Collection and Safety Forum)
From contributor A:
The two reasons which you've given as a criteria for deciding which DC to buy are valid - unfortunately, the numbers for those DCs are not. The cfm ratings on most consumer model DCs, are expressed as "max cfm", which is "free-air" delivery. That would be the maximum airflow, with no ducting installed, or filters. It may not even include the blower outlet transition flange, and the pipe running from the DC to the bag-tree, just the blower alone. Unless you specifically see a "system performance curve", you really have no idea what that DC will flow, nor at what suction pressure.

If that DC has a 5" blower outlet, expect no more than 900 cfm with a very short 6" diameter test-pipe. Filter pressure-drop will also affect that rating. Used as you've described however, you should be fine.

The same goes for micron ratings. Basically, when a vendor offers a 1 micron filter, he's telling you it's his best quality filter. They routinely vary from 30 micron for the poor quality filters, to 1 micron, for the better quality felt bag-filters or canister filters. Virtually all of those fine particle capture ratings are optimistic to say the least. Ask your vendor what cloth weight they use for the filters. A 16oz needle-felt will have a better filtration spec, than an 8oz, or 10oz filter. Surface area can also play a significant role.
Look for good particle release characteristics, and high air-permeability. The Delta that you've mentioned is part of Delta's new line-up. Those DCs have some of the best filters I've seen among the consumer DC brands.



From the original questioner:
Thanks for the quick response. Now I’m focusing on Delta 50-760 and JDS 14040. I couldn't find the blower outlet specs on both models from their websites. These are some things I've found from those websites:

JDS:
impeller dia. 11"
decibels 67-77
static pressure 12"
CFM 1250

Delta:
impeller dia. 11.5"
decibels 88 ( this is loud)
static pressure 8"
CFM 1200

They both have the similar things:
inlet dia. 1 - 5" and 2 - 4"
1 1/2Hp motor
1 micron bag

Delta has larger impeller but less static pressure. I think from the same inlet diameter, the machine that produces more static pressure should be stronger, is that right? If that is right, I'll get the JDS.



From contributor A:
I wouldn't pay too much attention to those DB and SP specs either. It's a shame to have to tell you that, but it's just the way it is. Some are measured at 10 feet, others at 3 feet, etc. Some measured in a large warehouse, with the tester facing away from the DC, others in a smaller room with the tester facing the dc. It really boils down to this. The one that moves the most air will be the loudest. It's the air coming off the impeller tips that makes the noise.

You can easily make a muffler for those DCs if you find it too loud, or build an enclosure. With a 1-1/2 hp unit, serving one machine at a time, noise levels should be pretty low anyway. SP levels for those DCs, are expressed as "Max SP". Again, that's meaningless unless it's accompanied by a cfm rating. It has to be a rating for the fully assembled DC, with filters and ducting. As it is, it's stated for the blower alone, without the outlet transition flange mounted to the blower, nor the transfer pipe, from the blower to the bag-tree, nor the 5" port at the bag-tree. With a DC like the JDS, you can expect a total suction pressure of roughly 2.5"wc, with a 5 foot long, 6" diameter test-pipe, fitted with a bell-mouth fitting on the test-pipe. That assumes an airflow of roughly 860 cfm, which I think would be optimistic with an 11" impeller, and 5" blower outlet.

With a 5" inlet and test-pipe, suction pressure will be higher, but you'll move less air. With a 50 inch long test pipe (10x diameter), expect roughly 800 cfm"at" 4.95" WC total suction pressure. That'll give you 2.15" WC for velocity pressure, and 2.8" static pressure loss, with a bellmouth fitting on the 5" test-pipe. Total pressure, is the sum of velocity pressure, and static pressure losses.

You don't want to drop below 1" velocity pressure if you have ceiling-mounted ducting. That'll give you 4000 fpm for your drops. If you're simply running horizontal pipe from the DC to the machine, you can go to just above .75" velocity pressure (3500 fpm). That would allow a max sp loss of roughly 4.1"sp -4.2"sp for that branch. If you're using smooth-walled 5" metal pipe, and you use ceiling drops to your machines, expect to use no more than 53 feet of pipe. Remember, you have to convert all the elbows and turns along that run, to an “equivalent length" of straight-pipe. If there are three 90 degree elbows along that run, each will have the same resistance as 12 feet of straight-pipe, so that's a total of 36 feet. That leaves you 17 feet for the straight sections, for a total of 53 feet. You'd be flowing roughly 550 cfm with a 5" hood.You can go a bit longer if you don't use ceiling drops. A horizontal pipe only requires 3500 fpm. In a 5" pipe, that's roughly 475 cfm (3486 fpm). That would allow you to use up to 84 feet of equivalent length.

Remember also, that all of these numbers are with a clean filter. You'd want to allow for filter loading, and the corresponding suction pressure drop. Keep those runs efficient, by using long-radius turns, very little flex-pipe, and a well-tapered hood. One last note, I based those numbers on previous test-results from models similar to the JDS (11" impeller/5" inlet/outlet). I used a 4 foot test-pipe (10x diameter), and a bell-mouth fitting, and 800 cfm. If they used a 10 foot plain-end pipe for their test, your actual airflow results will be higher. At 800 cfm, you'd have a total pressure of roughly 7.42"wc. I'd seriously doubt that they'd use a plain-end pipe to get 800 cfm in that test-pipe. The brake-horsepower requirement would be too high. If they used a bell-mouth fitting on the end of the test-pipe, then your total pressure would be 5.5"wc. That also falls into a sensible brake-horsepower area.

The Delta is a "different kettle of fish". There is no blower outlet transition flange, and I'm told the total area of the outlet is greater than a 5" diameter round outlet. This may account for the lower SP rating. There's simply no way to tell what either of these DCs are actually pulling, based on those specs. I suppose that 8"SP might be possible with no filter and ducting present. That would translate to about 895 cfm.

With a 50" plain-end test-pipe (10x diameter), that would be roughly 870 cfm. With a 10 foot plain-end pipe, that would be 830 cfm. This doesn't appear unreasonable, considering the 11-1/2" impeller, 5" intake/ 5+" outlet, and oversized filter.

I may have the opportunity to perform a test on one of those in the near future. I'll get back to you with the results.



From contributor B:
Have you considered the DC2000B from Penn State? To me if seems a good DC, reasonably priced with interesting specs and a 6 inch inlet. To contirbutor A: What is your impression of that Penn DC?


From contributor C:
Is there an advantage or disadvantage of having the fan/motor assembly up high as in the 50-760 unlike the 50-850 which has it located lower?


From contributor A:
To contributor B: You asked about my impressions of the Penn State 2000B DC. I can only respond by saying that if that DC meets your needs, it's a good DC for you. I firmly believe that the choice of an effective small-shop DC begins with properly identifying the air requirements of your individual shop, and machinery.

Small DC's often require meticulous attention to duct design efficiency if they are to work effectively. Understanding and adapting to the limitations of a particular model can be paramount to your satisfaction.

Obviously, the two key requirements are air delivery and filtration. Make sure the DC you choose has not only the cfm required to clear your machines of waste, but also the suction to transport that volume through your ducting. You also want filters that breathe freely, and filter the air to an acceptable level. You want to avoid filters that fit poorly to the DC, allowing dirty-air leaks.

Electricals can also play an important role in your choice of an appropriate DC. The DC will become the most-used machine in your shop. It'll be running simultaneously with your other machines. Are the electricals capable of dealing with that task? This may involve long periods of continuous operation, or frequent on/off cycling. You may want to consider a motor with manual thermal overload protection, and/or a motor rated for "continuous" duty-cycle operation.

A bargain DC is never a bargain if you immediately have to turn to upgrades to achieve the desired results. Assess your needs dispassionately, and then try to find the answer to those needs, at a price that is acceptable to you. If your budget determines the final choice, be prepared to make the necessary compromises. Prioritize what the most desirable features are for you, and adapt accordingly. This may mean using little or no ducting, (direct hook-up), frequent cleaning of the filter(s), and intermittent use of the DC.

I don't know that PSI 2000B well, but I'd assume that it can deliver close to 800 cfm to one major tool such as your table-saw (400 cfm to base/400 cfm to overarm blade-cover). It would have to be situated close to that saw. From there, you can run a 5" pipe to a 12"-15" planer and 6"-8" jointer. Here you have some flexibility, depending on pipe layout. Use properly sized hoods, avoid unnecessary elbows, and use flex-ducting only where absolutely necessary.



From contributor A:
To contributor C: Each type offers its own particular advantages. With the 50-760, you can have the blower-inlet facing either up, or down. If you're running a ceiling-hung main, that upward facing inlet eliminates a 90 degree elbow to rise to the ceiling. Also, you can use a 6" pipe to rise to the ceiling, then a 6" elbow at the ceiling-turn. This will reduce resistance, and add a little extra "reach" to your duct network. You might even use 6" pipe for your main, to your first machine-drop.

On a DC like the 850, you can mount your ducting along a wall, at blower-inlet height. This will eliminate vertical drops to your machines. It will also eliminate unnecessary elbows and fittings, and significantly reduce the pipe-length from your DC to a machine. A horizontal pipe only needs 3500 fpm for adequate waste-particle suspension. With a 6" pipe, you'd only require 685 cfm flowing through that pipe. If you used 6" ceiling drops to your machines, then your DC would have to be pulling a minimum of 785 cfm through that drop, for a velocity of 4000 fpm. You'd most likely require four 90 degree elbows on that run, plus the riser and drop pipes. It would be much more efficient to go direct along the wall, and cheaper too.



From contributor C:
Thanks for the reply. If you had to pick between the Jet 1100, Delta 50-850, Delta 50-760, and the JDS 14040 for a garage workshop running a lathe, planer, table saw, drum sander, and disc sander, what would you buy and why?


From contributor A:
I'd need more info in order to answer that question appropriately. How much air are you hoping to move at each of those machines? Right off the bat, I'd narrow it down to the two Deltas. The 50-760 has an 11-1/2" impeller, and one of the nicest quality filters I've seen on a consumer model DC. The entire new line-up of Delta DCs share that same filter quality. The Deltas also tend to go with motors that are rated for continuous duty-cycle operation, and include manual thermal overload protection.

The DC-850 has undergone a few model changes over the years. I'm told the latest version has a 12" impeller, and the blower outlet is 6". That outlet will provide less back-pressure than the 11" impeller Jet, or JDS, with their 5" outlets. The 850 also has a 6" inlet, but there is a 4" restriction-collar just inside the blower's 6" inlet cover. This restrictor is simply tack-welded in place, and would be quite easy to remove. This would increase airflow significantly, but you have to ask yourself "Why did they add that restrictor in the first place?"

Using that DC in an unrestricted fashion, you'd probably easily overload the motor. "Unrestricted" means a very short, but large diameter pipe, and/or venting outside, with no filter. As long as you use the appropriate ducting, you should be fine. That ducting will introduce resistance, somewhat limiting cfm to a safe level. I'm not a fan of cartridge filters on a single-stage DC however, especially with the drum-sander you referred to. I'd go with two high-quality needle-felt filters.

The 50-760, has an 11-1/2" impeller, great filter which has been over-sized to 20.5 sq. ft., thermal overload protection, and probably a motor rated for "continuous" duty-cycle operation. Certainly looks like a lot of bang-for-the-buck, for a DC in this price range. Excellent fit and finish as well.

One nice thing about the Deltas - they're available locally, so no shipping charges to deal with. This DC should have no problem pulling 800 cfm at a table-saw, as long as it's placed close to the saw, and properly ducted. From there, you could run a 5" main to your other machines, with roughly 450-650 cfm air-draw at those machines. Don't expect miracles at your lathe. This is probably one of the most difficult tools to deal with, especially with a small DC. You'll have to experiment with different hoods, depending on the operation you're performing (sanding, spindle-turning, hollowing, etc). Expect frequent filter cleaning with the drum sander. Give that filter-bag a quick shake if you notice a drop in your suction.



Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?


Have you reviewed the related Knowledge Base areas below?
  • KnowledgeBase: Knowledge Base

  • KnowledgeBase: Dust Collection, Safety, Plant Management

  • KnowledgeBase: Dust Collection, Safety, Plant Management: General


    Would you like to add information to this article? ... Click Here

    If you have a question regarding a Knowledge Base article, your best chance at uncovering an answer is to search the entire Knowledge Base for related articles or to post your question at the appropriate WOODWEB Forum. Before posting your message, be sure to
    review our Forum Guidelines.

    Questions entered in the Knowledge Base Article comment form will not generate responses! A list of WOODWEB Forums can be found at WOODWEB's Site Map.

    When you post your question at the Forum, be sure to include references to the Knowledge Base article that inspired your question. The more information you provide with your question, the better your chances are of receiving responses.

    Return to beginning of article.



    Refer a Friend || Read This Important Information || Site Map || Privacy Policy || Site User Agreement

    Letters, questions or comments? E-Mail us and let us know what you think. Be sure to review our Frequently Asked Questions page.

    Contact us to discuss advertising or to report problems with this site.

    To report a problem, send an e-mail to our Webmaster

    Copyright © 1996-2016 - WOODWEB ® Inc.
    All rights reserved. No part of this publication may be reproduced in any manner without permission of the Editor.
    Review WOODWEB's Copyright Policy.

    The editors, writers, and staff at WOODWEB try to promote safe practices. What is safe for one woodworker under certain conditions may not be safe for others in different circumstances. Readers should undertake the use of materials and methods discussed at WOODWEB after considerate evaluation, and at their own risk.

    WOODWEB, Inc.
    335 Bedell Road
    Montrose, PA 18801

    Contact WOODWEB











  • WOODWEB - the leading resource for professional woodworkers


      Home » Knowledge Base » Knowledge Base Article