Hot Rodding a Harbor Freight 2hp Dust Collector #1: Project Overview

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Blog entry by Kenny posted 02-23-2012 08:42 PM 11319 reads 2 times favorited 13 comments Add to Favorites Watch
no previous part Part 1 of Hot Rodding a Harbor Freight 2hp Dust Collector series Part 2: Step #1: Larger Filter Bag »

I received my HF 2hp DC a couple days ago, and resisting the urge to start the mods right away, I assembled it 100% as is stated n the manual. This way, I can get a good baseline as to how it performs from the factory and how well my mods work to improve it’s performance.

I will be looking at the improvements in a few different ways: #1- Fine Dust Collection: How well it collects fine dust and particles vs letting them pass through the filter and into the air in the shop #2- DC Efficiency: How much dust and debris is collected in the collection bag vs the filter #3- Separator efficiency: How much dust and debris is collected in the separator vs how much passes to the collector #4-Noise-How much more or less noise the system generates after modifications #5-Cost- How much each modification would cost the average person if they were to purchase the materials used in each upgrade #6-Overall performance gain or losss- This will be somewhat subjective and based on my opinion to some degree. But basically an overall judgement of how much performance each upgrade has netted or cost the system.

I am looking for a reliable way to measure the flow of the system so I can give an accurate reading as to how each modification effects the air-flow. I will include this as soon as I find a solution or someone makes a suggestion.

I’m hoping to gather all the information needed for someone who wants to maybe get a bit more performance from their collector without spending a ton of money or upgrading to a larger collector.

If anyone has suggestions for modifications, please post them in the comments. I’d love to hear them and any I like, I’ll most likely try and report back with the results.

Thanks for reading!

-- Kenny

13 comments so far

View SASmith               's profile


1850 posts in 3011 days

#1 posted 02-23-2012 08:54 PM

I use a kill a watt meter to test the amperage of my DC before and after each mod. The more restriction you have from too much pipe or a clogged filter the less amps/watts used.

-- Scott Smith, Southern Illinois

View DIYaholic's profile


19623 posts in 2699 days

#2 posted 02-23-2012 08:59 PM

I too am interested in observing/calculating/documenting air flow/CFMs! I have the 2HP HF DC with the Wynn 35A274NANO cartridge filter. I have not done the “Hot Rod” modification yet ie. reposition motor/impeller, Thein Baffle, ducting to/for each machine/tool. That will happen once my air cleaner is finished & installed and I finish a REAL WW project.

I will be watching this thread for your solution for measuring air flow/CFMs along with your progress & results.

Good luck,

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View NBeener's profile


4816 posts in 3198 days

#3 posted 02-23-2012 09:12 PM

I love these threads.

How much do you want to know ?
How badly do you want to know it ?
What are you willing to spend to find out ??


I’ll be watching …. :-)

-- -- Neil

View b2rtch's profile


4861 posts in 3072 days

#4 posted 02-23-2012 09:38 PM

Here is what I did with mine:
It works great

-- Bert

View ptweedy's profile


75 posts in 3417 days

#5 posted 02-23-2012 09:43 PM

I have seen a cone like devise that is attached to the inlet hose that can be slid toward and away from the hose end to restrict the quanity of air entering the inlet. A mercry tube that measures vacuum could then be inserted into the air stream and finally a amp meter could read the power lines to graph the whole works. I have seen this equipment being used on a website about how big the runs of pipe should be in a vacumme set up. Dont use the hand over the inlet method it is very hard on the manicure. phil

View rkober's profile


137 posts in 2316 days

#6 posted 02-23-2012 10:50 PM

A water manometer should provide you with a way to quantify your performance. I would not mess with mercury when you can do it with water. You can do a search for the theory as it’s a little sketchy in my mind after 20+ years since fluid dynamics class.

-- Ray - Spokane, WA - “Most people don’t recognize opportunity because it’s usually disguised as hard work.” - Unknown

View Kenny 's profile


260 posts in 2472 days

#7 posted 02-24-2012 12:15 AM

I should have thought o the manometer. I’ve used them before on the flow-bench at the engine shop I used to work at. Been about 10 years or so since then, so I can’t quite recall specifics on how to set it up, but I’m sure a google search will lead me to the info I need. And no, I don’t plan to play with mercury. (can you even obtain it legally now?)
Thanks for that!

Metering current draw would be a good help to see what I have for resistance in the system, but I don’t think it’s a good way to judge flow. It would tell me when I have reduced resistance in the system, but I still wouldn’t have any idea how much flow I had gained. Though it will be a useful tool in mapping overall performance gains in the system.


-- Kenny

View Kenny 's profile


260 posts in 2472 days

#8 posted 02-24-2012 12:24 AM

Bert, you have done basically what I am going to do, with the exception of the cartridge filter. I simply do not have the $168 for the filter right now. Someday.

I have some good ideas I’m going to try, like Thien vs Cyclone, which is something I feel a lot of guys wonder about, whether it would really be of benefit to step up to a true cyclone from a Thien baffle. It’s something I plan to find out, as I’m just too curious not to!
And whatever works best, I’ll keep! I have a buddy who is going to pick up a HF DC soon, and I’ll sell him whichever I don’t keep for what I have in it for parts.

I’m trying to decide between buying a cyclone from Cyclone Central in the UK, or making my own from sheet steel or possibly acrylic sheeting.

-- Kenny

View Martyroc's profile


2712 posts in 2330 days

#9 posted 02-24-2012 12:36 AM

I can’t wait to see what you do, I only have 2 shop vacs myself, and I am making a cycling dust collector. As soon as I can come across a good motor and a squirrel cage blower I will incorporate that, which is my final destination. I created a blog if your interested here’s the link.

-- Martin ....always count the number of fingers you have before, and after using the saw.

View b2rtch's profile


4861 posts in 3072 days

#10 posted 02-24-2012 10:25 AM

You can buy a decent cyclone on Ebay for around $200.00 ( the last time I checked around a year ago)

I have been thinking about buying one but my installation, as it is, gives me 100% satisfaction and total I spend probably less than $250 for it

-- Bert

View bowtie's profile


990 posts in 2370 days

#11 posted 02-24-2012 11:06 AM

Kenny, I’m curious about flow difference cyclone vs thien. You can see my H.F.D.C. modification at bowties projects. What ever you choose build a system that allows easy can removal and gets most debris into the can.
I hated the inconvenience and mess of emptying the bag, and it really fills the shop up with dust when you proctastinate and over fill the bag. I have only about 20 feet of 4 ” pvc with drops to 5 machines and a rockler expanding hose so my dc’s performance didn’t seem to be hurt by my mod.

-- bowtie,.....jus passin thru....

View b2rtch's profile


4861 posts in 3072 days

#12 posted 02-24-2012 11:12 AM

” What ever you choose build a system that allows easy can removal and gets most debris into the can”
This is exactly what I believe I have achieved with “my ” modifications ( in fact many other people ideas put together).
Since my “total make over” I have emptied the trashcan countless time but the plastic bag still has no more than may be 2 inches of fine dust at the bottom.

-- Bert

View History's profile


399 posts in 2005 days

#13 posted 03-04-2013 12:25 AM

I’ve seen what Bert and others have done with the HF 2 HP DC and I have allways wondered if operating a motor vertically that was meant to operate horizontally was ok to do. So far from what I’ve been able to find on the internet for information suggests that it’s not ok because a horizontal motor does not have thrust bearings that a vertical motor does. Do not expect the motor to have a full life.

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