J. Phil Thien's Projects

No matter what you do to the size and shape of those holes, they will still place an edge facing the swirling airstream.  The length and moisture content of the shavings will determine how quickly the clog will occur, but it almost certainly will.

There is another concern I have and it is hard to predict the impact on the separation until you try it.  If you can find the videos I posted showing the performance of my separator, you will notice the air swirls with somewhat of a sine wave pattern.  It would seem the separation occurs in the valleys of this wave, and if that valley happens to be where you have placed these bridges, I think separation will suffer and you will get unwanted turbulence.  However, this is just my guess.  But if it were me I would be looking at other ways to support the baffle.  I have a threaded rod post to support mine.  It is set back so it has little or no impact on performance.  And when i was trying to plane very wet Cypress and plugging my separator one time after another, the post was never the culprit.  The plug always started at the end of my drop slot, and you are essentially adding several of these ends points to catch shavings. 

There are a lot of unknowns with what you are trying to do, and I?m just guessing based on what I?ve seen with my system.  So whatever you do, be careful not to modify your baffle plate so that you cannot return to a more conventional drop slot configuration if necessary.

I don?t remember where I saw them, but I?ve seen descriptions for building noise reducing enclosures for a DC system.  They are small closet sized enclosures so they don?t take up a lot of space and if done right are pretty effective at reducing the noise.  They vent back into your shop which is what you want.  I?m not sure I could stand working in a shop with a 3 hp system without some serious noise suppression. 

The best filter to use is a cartridge style pleated filter like the one you are looking at. They have about twice the filter area of a bag style filter.  As far as size, call the manufacturer they should be able to quickly recommend one suitable for your system.

If I am seeing correctly it looks like your drop slot has several bridges to keep the central part of the baffle supported.  If that is the case, don't plan on collecting anything but sawdust.  Shavings from a thickness planer or jointer will completely plug this separator in minutes.   

Well of the three tools you mentioned, only the band saw is easy to collect the dirt and dust.  The others will require moving much more air.  I'm not a fan of 1 HP blowers in a centralized DC system.  They generally only move half the air of a 1-1/2 or 2 hp system.  Put an expansion on your breaker box and get the circuits you need.  My blower runs on a 20 amp 120v circuit that is not dedicated so sometimes I am running another tool with it.  I've never tripped a breaker, but my blower is always running by the time I turn the tool on.  I have a 220 v 30 amp dedicated circuit for my thickness planer, but everything else runs on a 20 amp 120 v.   

Grant, I?m not sure your scripture would be quite as accurate if I substitute ?play? for ?toil?.  I never thought of any of my time spent in the shop as toil.  And for sure my wife always thought of it as playtime.

I?m not sure I follow you Alan, but here is my DC:

https://www.finewoodworking.com/2006/04/01/50-760-portable-dust-collector-review

There Is nothing that can be done to modify it without destroying it.  I replaced the bag filter with a pleated Wynn filter and just left the plastic bag alone.  I could dramatically shorten the bag, but there is no point in messing with it.

And most importantly, the amount of work I do in my shop no longer justifies any equipment purchases or time spent modifying what I already have in place.  I?m at the time in my life where I am starting to worry about leaving someone with the task of dismantling things and selling it off.  There are drawers and cabinets filled with accessories, and no one but me knows what belongs to which tool.  I suspect an heir will bring in a local auction house and ask them to buy it at a dime on a dollar and remove it!

My Delta DC is in fact a two stage separator as you describe. Actually it is just one, but my top hat brings the count to two. Unfortunately, the Delta is built in a way that the I cannot remove the second stage without destroying it, or I would.  Over a long period of time the second stage has separated a small amount of fines, but the price is full time system losses. 

I really question the value of a second separator.  I?d argue that the first top hat will separate more than 90% of your waste with a system loss of 35% or more.  Add a second separator and the system loss is likely to be as great or even greater than the first.  And you are adding all that loss to MAYBE capture another 1or 2 % of waste.  Keep in mind the second separator won?t see anything but fines and separators are not very good at separating out fines, so most of it is going to wind up in your filter.

If you think my numbers are a bit extreme, consider this.  I have emptied my waste drum more times than I can count.  The bag under my pleated filter has never been removed and the amount of fines in it would not fill a 1 gallon can.

I think you are going to have a top heavy, unstable dust collection system that is probably going to underwhelm you with its performance.  You?ve already mentioned mounting it on a wall.  If you do that, it will no longer be close to all your tools unless you bring all the tools to the dust collector.  If you add pipe or hose to that design, I fear you may not have enough velocity to keep the waste entrained.

And I bet many people who start out with the intent of moving their dust collector to each tool, soon give up.  Consider the simple task of dressing and sizing a piece of stock.  You will use a thickness planer, a jointer, and a saw, and you will spend far more time moving your dust collector than using those tools.

There was a restaurant in Usuahia called Marisco?s that I really enjoyed.  My wife and I went back several times in the two days we were there.  Flying into Usuahia on a plane is an adventure in itself.  Maybe it isn?t much in the summer, but we landed in very early spring with fog and sleet.  Snow was just starting to melt off the mountains.  The  National Parks of Argentina and Chile are out of this world beautiful.

That?s quite a story!  You have a few years on me, I?ll be 75 in a couple months.  I just assumed you were from the US because you?ve got a great command of the language.  I suspect there?s more details in your bio that would explain that.  I regret to say that in all my South American travels I missed Uruguay, but I was close, Buenos Aires.  I?ve been to six countries there, working and vacationing.  My work assignment was just a few months long in Salvador, (Bahia) Brazil.  Our best trip was our Patagonian adventure.  Maybe I?ll come back to visit Uruguay and Paraguay!

Quote from: earnsdorff on April 24, 2020, 08:44:53 PM
I'm new to the Thien baffle and I'm building my 2nd version to see if I can improve on my first one from the lesson's learned.
I saw that this thread showed using a single measurement of air velocity from a vane anemometer to somehow calculate CFM of the flow.  I have a great deal of experience with measurements of air flows and such (so far none of the nuclear plants that have relied on my analysis have had an issue and many other systems as well).  I don't see how this measurement method will produce anything close to accurate measurements.  If you maintained the measurement in the same location while changing only other aspects far removed from this flow area then it may be effective in seeing a relative effect.  But making changes at the inlet section where the measurement is made and using the vane anemometer to see the maximum air speed (I guess this is what is being done) doesn't equate to volumetric air flow. 
I think the differences are due to the measurement method and this is why the results don't follow logic.

About the only thing you?ve said that I agree with is that using a cheap anemometer at the end of a straight pipe is not the most precise method to measure air flow for a particular setup.  That said, we are dealing with home shop dust conveying systems here, not rocket design.  If our measurements are accurate to within 25-50 CFM, it is plenty good.

I hope you agree it is a straight forward calculation to convert FPM to CFM for a given size pipe.  Secondly, the precision of the measurement is less important than the repeatability.  For a given setup and a given anemometer, you should be able to take a hundred readings and they should all be reasonably close - for sure close enough for dust conveying systems in a home shop.  So the methodology described here is plenty accurate to determine relative performance, i.e., how changes to the setup effect the flow rate.

In the thread on my top hat build there are several tables of data presented for various configurations I was testing.  Most of the tables also include power measurements to help validate the flow measurements.  Even noise levels are included.  Admittedly power and noise are not very sensitive measurements for measuring flow, but they should support the flow measurements.

So, I rest my case by stating I have taken many, many measurements testing my various configurations and plumbing.  They were all done with the same cheap anemometer.  The results have always been consistent, and made perfect sense with the CFM and SP rating of my blower.  So I would continue to recommend this methodology to anyone wanting to know something about the relative performance of their system and various configurations.  When someone gets a number that is out of wack, it is far more likely to be a design or construction problem than it is a measurement issue, assuming the methodology described in previous posts is followed. 

Oh, and for what it is worth, and it is not much, for several years I worked in the organization that designed, built and operated the Savannah River Plant for the U.S. Government. 

About 50 years ago in one of my last carefree summers I took a job with a surveyor.  I was the rod man, but I still learned a lot.  The one memory I will never forget was surveying the centerline for a new road that had to go through a gentleman?s property who threatened to shoot anyone who stepped on his land.  We had to survey a long radius curve through his property.  There was a lot of dense brush which made surveying difficult, but it kept us out of view.  So, to minimize exposure we decided to survey in from both ends.  After a couple days work we discovered our center lines were going to miss rather than join in the middle of the property.  The boss wasn?t too happy, so we had to start over after finding the math error.

So, that summarizes my surveying experience.  I know the technology is so different from then.  That was fifty years ago.  Since then I worked 37 years for DuPont doing Engineering.  Along the way I became a photographer, a golfer, a woodworker, a pool player, a genealogist, and world traveler.  I?ve had a good wife and a good life, so there you have my life story!

Oh, and thanks for the compliments on my posts. 

I must say the shop built table saw is a very impressive piece design and piece of work.  I?m not sure I would tackle it because it looks like controlling costs would be a problem, but I have no space for a table saw of this size.

With regard to your dust collection, why are there so many ports?  Do they serve more than the table saw?  Where is the blower?  That porting arrangement has some very high SP losses, but is still very workable if only the saw is being served and the blower is a shop vac which has very high SP, but very low CFM.

The OP was not very clear about what he was trying to do, so it is hard to say if the multi-porting will work for him or not.

Quote from: Tacuabe on April 14, 2020, 05:47:35 PM
Hello:

I've had very good results with a 4 blast gate input linked to a tophat separator. All that inside a shop-built table saw. Here's the link to what may help you with your project: Shop-made Table Saw with integral Thien DC.

The saw has now been published in an improved version in our web page www.aw-thinkbold.com. You'll find there some additional photos of a cleaner layout of the blast gates. The original ones were just an addition to the existing prototype and were conditioned by the connections inside the available space.

Please let me know if you need any more info to carry out your build.

Best regards

Where are the photos of the blast gates?  A better link or more specific instructions would have been helpful.  I spent too much time and never did find anything.  I finally came to the conclusion your post was more of a plug for your saw plans than an effort to help the OP!

Quote from: Inspector4 on April 09, 2020, 12:51:42 PM
I used 1/8? Masonite smooth both sides for the baffle plate.
I added the top hat because my DC intake opening has a metal protector that also caught the shavings and plugged the 4? DC hose. Really don?t Want to cut the protection out but probably the only way to not plug things up.
Thanks for the replies.

I just reread your first post.  Is your DC on a cart and moved to each tool, or is it stationary and piped to a central location?  If it is the latter, how long is the piping and how many turns and fittings, i.e. laterals or hopefully not T?s?