my best harbor freight mods, thoughts, intro.

[Clark Savage Jr]

As a first post I am throwing this out for whatever comes back. If I make a mistake, correct me, it has happened before. If I repeat others, sorry, these are my opinions - some calculations, some training.

My HF-DC modifications I consider as best before/after a Thien baffle. The HF-DC is basically the same as MANY other higher rated DCs. They are all made in China and not everyone makes their own unit. I am NOT including all my internals or other changes/Thien permutations as everyone has different ideas on that subject. I do believe the modifications I am presenting will provide noticeable/measurable improvements out of the box no matter if you Thien, other or not. Perhaps they have been covered, if so, sorry. Still this is my experience and if nothing else a reassurance that someone else has indeed done them.

FIRST, the best health benefit is from using a Wynn Environmental Cartridge Filter. No matter what you do, how many stages, can, cyclone or other - the filter is the LIFE SAVER. No one knows how many failed modifications I have tried in the pursuit of better separation - and the filter saved my %#$@ and prevented days of cleanup inside my home. My filter: C1425C  Nanofiber, MERV 15   99.999% @ 0.5 Microns, Single Mounting Flange with pre-drilled holes, 18.75" OD, 14" ID x 25".

Second best modification, I ordered a Rikon impeller for my HF DC. That took me to new flow heights -  impeller size from a 9.75" diameter to a true 12" diameter. Rikon - 877-884-5167 - ask for parts, do NOT talk about your HF-DC, state you need an impeller for a 60-200 DC, part #22 for the impeller. Part #26 for a new bolt and part #27 for the "spring washer". You can use the old bolt and washer - I did - but bought the new ones anyway [why you ask - because I am that...]. Total cost for all of it - $120.27 including S&H. Download the Rikon Manual for a 60-200M3R.PDF and check for yourself - suggest you always do so. No issues with the HP everyone talks about with a bigger impeller - it just works. Helps all those SP and other frictional issues big time.

Third, the inlet to impeller is 5" - actually slightly smaller. Open it up to a to a 6". Amazon sells - Big Horn 11603 6-Inch By 4-Inch By 4-Inch Y-Adapter - for $13.99 allowing more air in. I cut a wood ring, epoxied it to my intake plate to mount it to. I epoxied it first, using the old hole to center it as the new ring and then cut/ground/sanded the sheet metal plate holding it to the inner diameter of the 6".

Calculations based solely on close [NOT exact] physical dimensions -  not considering frictional or other components:  HF ~5" intake area 19.6sqin {less actually - it is NOT 5"}, ONE  4" intake area of 12.57sqin, TWO 4" intakes an area of 25.13sqin, ONE 6" an area of 28.27sqin - so flow two 4" to the 6" whereas I can not with the SUB 5" intake.

If you change the fan housing exit from the hose to the rectangular housing exit, by remounting the stock blower [lots of you] and make it in-line with your new Thien can - rectangular exit 6" x 5" - area 30sqin. Those area numbers are beginning to line up.

Simply matching and straightening ports in-line/areas in a NEW can - helps to offset any pressure and flow loses you may get from adding better separation. That impeller will really help too.

We all realize, the HF can along with most others has a lot of flaws you can not overcome if you want better than a little. Can height and inlet positioning/angle/flow - the dish, once you add to it, well, flow is limited and scavenging is compromised simply by the Physics of it. You are confined to a number by the can, which is one reason the larger, rebuilt Thien cans really shine. If you are two staging with the stock can, then you are still compromised and limited. This goes for a lot of other same style DCs.
Flow "straighteners" discussed many times by retired2 and he is correct. Any flow stabilizer will help. Yes, in-line to the impeller and in-line within the fan outlet/inlet to the "can" should be tweaked with vanes that allow the particulate dust in the column to migrate outward with the centrifugal force imparted by the curve and not allowed to create air boundary layers. The fine lightweight particulate can be suspended in a moving air column and at times will not penetrate the individual velocity boundary layers created by other means.

Bellmouths - CHEAP - as "speaker port tubes" - "Pair of 6" ABS Speaker Ports" on eBay for $18.95 with free shipping, Parts Express and Amazon have them too. A flat horizontal ring extension at the end of the tube - if no bellmouth - would be the second best option.

Suggested health reading for new site visitors -  www.cdc.gov/niosh/pel88/wooddust.html
  Also interesting:  www.osha.gov/SLTC/etools/woodworking/production_wooddust.html

On OSHA's site "Sanders, shapers, and routers generally produce the greatest amount of dust. Conventional means for exhausting these machines are not very effective. NIOSH has developed new, innovative means for controlling dust exposure from these machines, but these methods are not yet commercially available" - cute. Most of us see with our our eyes and experience that high speed belt sanders/slow FPM router cutting will create very fine dust. I save some of the fines and use it as wood flour in some of my epoxy glue ups. Most acknowledge that saws will create coarser dust and planers the coarsest - generally.

I am a consulting engineer with some experience in related fields, not directly related to any hobby dust collection or other such scale OEM. I do not think I am the expert, never will. Forgive me if at times I sound like the authority when giving what I know - how else can I do it? Again, I am attempting to contribute just like everyone else. Many can think outside the box, the Thien baffle is a perfect example. Is a properly constructed/sized cyclone better - in my opinion the answer is yes. But I want something at home and running ten horse(+) with a ten foot (+) stack or a baghouse/electrostatic/shedding filter media/back pulse/shaker setup won't cut it at home.

Oh, sometimes running your outer bag inside another chamber will help if you have the room. Using it as a 5u pre-filter that is easy/easier to clean before the Wynn can really be beneficial. It will cake and if you can place a viewport in the chamber, you will know when. Using a home built simple "pressure meter" may help you check flows at various points in your setup. You can make one or use those CHEAP pressure meters on eBay or your favorite store. You may not get the right reading - but what we are looking for is CHANGE in reading from a CLEAN running system to one that over time is loading. You will develop knowledge of your setup and have a better idea of something that is wrong or time to clean. Obviously pressure gauge for blow, vacuum for suck applications or buy a dual meter.

I looked for and found a link to some info that you can check for pipes and flow - see what your added frictional/area straighteners/pipe runs are doing here too:  http://www.omega.com/green/pdf/AIRFLOW_MEAS_REF.pdf

So thanks to everyone, very interesting reading and maybe if it just works - like retired2's - then maybe that's the ticket. Sometimes too much - perhaps some of what I speak of - is just that, on a declining returns curve. Maybe some is insignificant in the scheme of things. But I am interested and hope to contribute for what it is worth to anyone. For me, it is about HEALTH.

Thanks Phil, and thanks for allowing me to join.

[pjr_atl]

Great stuff thank you.

Any chance you have any pictures of your work?

[NCTinkerer]

I just bought one of the HF 2HP Dust Collectors.  I'm planning to mount the motor/blower part on top of a separator then exhaust to a cartridge filter.  I'm very interested in the mods you have made.  Did you replace the impeller because you couldn't get enough airflow?

[Clark Savage Jr]

Sorry, been moving my mother and father into a retirement community so I have not been available. Still a work in progress.

I replaced the impeller because I wanted greater flow/less losses. The impeller - wish I had taken measurements but did not - significantly improves the HF. As I stated, much larger - outer diameter increase really adds to fan production. For the cost, I stand by it as one of the best mods you could make to achieve VERY noticeable change in suction and flow. I was finding at times [CNC, drum sander] I was producing more airborne dust than I wished and CFM flow was not keeping up. The impeller overcame a lot of my mods and I have done quite a few. I do not know how to convince anyone, but I would go on record stating you will love it. My HF has so many changes I will not go back and measure the difference - I can't. Perhaps if someone else on the forum reads this they will chime in, or perhaps if you read through this or other forums you will find some numbers. I have read others stating the HF flows anywhere between 400 and 800CFM depending on mods. I read someone with a cartridge filter [less restricting] claim 800CFM. Others claim 1000 to 1200CFm for Grizzly/Rikon/Jet units - they have the larger impellers. That's a significant difference if they are to be believed, and my real world experience is that they are most likely correct. That is a lot more flow - almost double. If you do it and do not think it was worth it, then call me bad right here on the forum - no issues with your experience telling it like it is. You want a better unit, get the impeller. The impeller change is the cheapest move to a Rikon or other maker equivalent DC out of the box - this takes the HF out of the CFM stone age.

If you increase any ports or make a top hat or other mod, it shines and you further reduce restrictions.

Add a Thien baffle and you enter a new level.

I, and many here, would tell you to improve the intake/exhaust throughout your build not just in the fan. For me, moving to the two 4" to 6" $13 mod you will reduce restriction significantly. You can still use it on your top hat inlet, if, like me, you wish to retain two 4" hose ports. Before, I had lackluster suction and CFM flow [my opinion] for CNC and room clearing airborne dust. Not anymore, two 4" sucks like a single HF 4" port connected with the other blocked. That's my take on the impeller/ports + matching. That also seems to match everyone's forum posts of twice the flow in the other units with the larger impellers.

I have attempted to post CAD images as JPG files, but have not been successful to date. My original is in pieces again, building a [HOPING] better unit - the reason for the CAD and not the unit. I have a strange arrangement in it I may post if I can solve my picture/image problem just for the comments it may generate. But that is not holding you back. It is not necessarily better than retired2's latest unit. I would be happy to take off my cover and post pics of the impeller change - but it is just that, side by side, but it is as I wrote, up sized from a 9.75" to a 12" and that alone should tell you what you need to know. There are impellers and such on eBay for sale, I figure why buy used when I get what I know fits and it is new? I checked it originally against a friend of mine's Rikon to make sure, and now it is a sore point that I saved a lot of money.

If I succeed with my new proposed two stage [two new cans is what I want] then if I feel the motor [HP] can't keep up then I may buy a HF 3HP motor that I have seen in the local store for $110. Truth is, I do not believe I will need it with the decrease in friction and other losses if I go to two full flow cans. Less to fight, less power required. Restriction/friction reduction is key.

Oh, get a cartridge filter would still be my rant - even if you get it first while you use your HF to cut your new Thien mod. Especially if inside your home like me. I converted a large room to a hobby room, and after I am done sanding, CNC cutting/shaping...... I have NO dust buildup in my home or workroom. I closed off the AC/Heat vents, recirculate in my workroom through the HF [yes, ports on tools] with the doors shut ONLY when working. Else the doors are open all day [cat likes to check the work progress] which I admit to work in your home is more likely NOT a good idea but I have to compromise in my neighborhood and I have no other space. I did install my own noise abatement to the walls, without it the concrete floor and drywall made the room an opera hall of machinery. My garage is full of other items.

So hope that makes you more comfortable and somehow healthier.

[NCTinkerer]

Do you recall if the Rikon impeller has a forward curved, backward curved, or straight impeller blade design?  The HF blower I just bought has the forward curved design.  My understanding is that this is to gain CFM at the expense of pressure and energy usage.  Reverse curved blades are just the opposite.  This was tough to grasp initially, but now it makes a little more sense.

[Clark Savage Jr]

You are correct in that the Rikon is a reverse of the HF.

In reality, the HF impeller is small, does not provide the pressure and flow the Rikon does. Now that I have figured out the image attachment [guess is not part of a preview to post] I am posting this photo for your review. You are correct on the vane design, but do not be fooled in what size means versus design in a fan. Yes, I agree, and I always look for and exalt the benefits of proper design and use - but this fits my unit and does the trick so it is still the one best increase in base performance [air moving] of ANY other mod I have tried or found at the price/performance point.

If I take your point and add in the larger fan diameter - do I not achieve more flow, more pressure, more.......?

That is not to infer I am the most knowledgeable or otherwise - but it works. Check other designs in the higher performance models and compare/see what they actually do with their fans. I think you would be extremely satisfied with this mod as a "seat of the pants" you can tell it is better as soon as you hit the switch. The pressure increase is substantial. I did this as a first mod. When I blocked one 4" inlet on the stock unit leaving the other one open, the bag was not  that stiff. After this mod, the bag was harder than leaving both 4" inlets open with the original impeller versus only one 4" open with the new impeller. So I would suggest that you will gain losses over the HF which almost stalls if not running as "open air" rather than moving a filled stream. Add other mods and you gain back - in my case - more than I lost - personal experience. Very substantial.

If you require shaft diameter and other I would be willing [since I am in change] to remove my fan and send picks of the shaft and dimensions if you desire.

Please do not take any of my comments the wrong way - I am only trying to help if I can. As always is the case, I think everyone should always think for themselves. That's what I like about this forum and the differing designs. Sometimes expected does not match reality due to other constraints that are exacerbated to the point that they become significant in the new design/use. I call it the change one thing and affect another.

This mod works for me no matter what I change and I would not go back. I will sell/give my old impeller away but will not part with my Rikon impeller. Would anyone want my HF impeller as a spare - will sell for S&H [cost] - because I will never go back. I hope that does not violate any posting rules.

[Clark Savage Jr]

I just reviewed my post - the Rikon impeller does not look bigger because it is behind the HF. Check this pic. 9 versus 12 [always the back plate]

[pjr_atl]

I am trying to understand your DC design....I am very much new to DC

I believe you opened up the impeller intake to 6 inches and then using a Y adapter to go into two 4 inch systems. Do you have 2 cyclones/Thien baffles connected to that?

Also a general question assuming at some point in the DC chain I have to drop to 4 inches... does having 6 inches before that matter? I.e. if I run 6 inch to my table saw and its dust port is 4  is this any better then just running 4 inches assuming I am only running 1 tool and 1 dc connection at at time?

[retired2]

I am trying to understand your DC design....I am very much new to DC

I believe you opened up the impeller intake to 6 inches and then using a Y adapter to go into two 4 inch systems. Do you have 2 cyclones/Thien baffles connected to that?

Also a general question assuming at some point in the DC chain I have to drop to 4 inches... does having 6 inches before that matter? I.e. if I run 6 inch to my table saw and its dust port is 4  is this any better then just running 4 inches assuming I am only running 1 tool and 1 dc connection at at time?

In response to your general question, it is quite common for main runs to be larger than the equipment drops.  So there is no harm in running a 6" line to your table saw's 4" port as long as your DC is able to maintain adequate velocity in the larger line.  A 1-1/2 HP DC rated near 1200 CFM should not have any problems with a 6" main and only one port open at a time.  However, a 1HP DC rated around 600 CFM might not be able to maintain the minimum velocity needed for conveying wood waste.

All things being equal, a larger pipe will have lower frictional losses than a small pipe, but conveying velocity will be lower in the larger pipe if the CFM's are the same.

[pjr_atl]

In response to your general question, it is quite common for main runs to be larger than the equipment drops.  So there is no harm in running a 6" line to your table saw's 4" port as long as your DC is able to maintain adequate velocity in the larger line.

<face palm>

ah of course I have seen that in many workshops now that I think about it.  Btw just finished reading your thread on your top hat design great work and information there. never would have considered flow straightening before reading that.

[knhuff]

Ditto Retired2 - Thanks for all the documenting and testing you did for all of us! Invaluable information!

Huff

[kayak]

Bought the HF unit in January, still haven't put it together, but have already made changes to it while in the process of building the tophat.  I've replaced the impeller with the Rikon, purchased a Wynn cartridge, and have replaced the impeller inlet plate with a plywood plate and opened it up to six inches.
Testing just the motor/impeller assembly on the bench without any filters on the outlet, or any ducting on the inlet, and using a clamp on meter to test the current draw, I am showing 80 amps startup current and 20 amps running current.  I have this on a dedicated 20 amp circuit.  I hope that once I get the system all put together, the current draw comes down some.  Otherwise I may have to put in new wire, breaker, and outlet...

[Jtull01]

Hi
So I built the HF mod. 20 gal trash can, Wynn filter, etc.
My problem is I get a vortex in my bag and barely any collection in the can! I used 5" metal duct into the Thien baffel and have a 6" drop from the lid. I have a 2.5" drop on the turbine tube into the lid, also 5".
Help what did I do wrong?
Thanks Forum
Jeff

[kayak]

Jeff,  could you post some pics of your build?  That might help us sort it out.
Zane

Hi
So I built the HF mod. 20 gal trash can, Wynn filter, etc.
My problem is I get a vortex in my bag and barely any collection in the can! I used 5" metal duct into the Thien baffel and have a 6" drop from the lid. I have a 2.5" drop on the turbine tube into the lid, also 5".
Help what did I do wrong?
Thanks Forum
Jeff

[kayak]

pics of jtull01's setup...
Any thoughts on what may be causing his problems?

http://i268.photobucket.com/albums/jj8/jtull01/IMG_3507_zps0zedjsjt.jpg
http://i268.photobucket.com/albums/jj8/jtull01/IMG_3508_zpsednokv9r.jpg
http://i268.photobucket.com/albums/jj8/jtull01/IMG_3512_zpsn0ytfvyp.jpg
http://i268.photobucket.com/albums/jj8/jtull01/IMG_3511_zpseln2pg2m.jpg
http://i268.photobucket.com/albums/jj8/jtull01/IMG_3509_zpsdnvtc7jn.jpg