Shopsmith Forums

Ooops, guess that should be "Science"

Hello all. My first post here.

I'm Mark, guitar builder in SW Indiana, Mark V owner with band saw and jointer. Soon to have a planer and SS dust collector (DC)...which brings me to my question.

I have been looking at specs on various DCs and I have also looked at the DC3300. I've noticed that the industry standard seems to be 4" hoses while the DC3300 uses smaller hoses in the 2.5" range...not sure of the actual diam. The DC3300 also seems to be under powered at only 330 CFM compared to the lower end DCs that have 4" hoses but move twice the air per minute.

OK, that wasn'r actually a question but here it is:

Does sucton work in a similar way to say water that is passed through a hose? An open ended garden hose flows freely but when you place a nozzle on it, it's pressure increases. So, then does the DC3300, using 2.5" hoses, @ 330 CFM create the same amount of suction as another model using 4" hoses @ 650 CFM?

Any takers? What would be the formula for figuring this out?

Peace,
Mark

Mark I can't help you on the question that you ask but welcome to the forum. I am confident you will get an answer here. I do know that the
DC3300 has ample suction for your Shopsmith as you will only be using one operation at a time.

Also
Mark

I am no expert either, but as I do understand it the following two facts are important to you.

1) The SS DC does go against the 'prevailing' 4", 2HP.... philosophies.

2) The important thing is velocity in the 'pipe'. Thus the smaller the diameter, the LESS cfm is required to maintain the minimum Velocity.

The SS DC works very well according to those who have one. The only possible drawback is the tendency of the impeller to break(keep large,hard stuff out of the flow) and the need for the larger 'filter hood'.

Hi Mark! Welcome to the Forum! You ask a very interesting, important and complicated question.
If I understand what I think I know about HP - 4" hoses - and CFM, It is really air movement, not suction that moves sawdust to the dust collector. The DC 3300 has been designed to use the proper amount of air movement through the proper size of tubing to do the job for our Shopsmith equipment.

It seems the manufacturers and sellers of Duct collecting equipment like to sell HP and 4" hoses.

Let me direct you to a few threads - Go to the search "button" on the red line above the page and click - then click "advanced search"- then type the name Nick into the user blank. leave "all posts by user". Then over on the left side of the page type in the word "dust" (without the quotes). Now scroll to the bottom of the page and click on search. There is no need to change anything else from the defaults.

You will get about a dozen threads where dust collection is discussed. That will just be a start! I think I remember a Sawdust session, or a shop tip about the DC 3300 set-up.

Hi,

Welcome to the forum!

Just one little note...
Area = pi*r*r
Where r is the radius and pi is 3.14.....

From that the you can see that 2-1/2" hose is 4.9 square inches and the 4" hose is 12.56 square inches.

So the next time you are thinking about what size/price pizza to order keep this in mind (just use 3 for pi as an estimate).

Now go to:
http://billpentz.com/woodworking/cyclone/index.cfm

Ed

reible wrote:Hi,

Welcome to the forum!

Just one little note...
Area = pi*r*r
Where r is the radius and pi is 3.14.....

From that the you can see that 2-1/2" hose is 4.9 square inches and the 4" hose is 12.56 square inches.

So the next time you are thinking about what size/price pizza to order keep this in mind (just use 3 for pi as an estimate).

Now go to:
http://billpentz.com/woodworking/cyclone/index.cfm

Ed

Do not worry about pi when comparing! Just remember the radius squared. Thus if the radius doubles, the area quadruples. If dealing with diameters(pizza) the same holds true. i.e. 12" pizza vs 6" pizza [6x6 vs 3x3 ==36 vs 9 == 4x!]

It is the RATIO SQUARED that is relevant. Thus a 6" vs a 18" has a RATIO of 3:1; squared = 9 YES an 18" IS 9 times larger than a 6"!!!!!

Hi Mark,

Welcome to the forum. You have definitely come to the right place to get you questions answered. You'll see there is a lot of expertise in this forum in all different areas.

This ShopSmith video link below will tell you all you need to know plus more for correctly designing a dust collection system.

The critical design specifications to maintain for proper dust collection is the VELOCITY OF THE AIR STREAM and STATIC PRESSURE You'll see that your looking for a system that gives you at least ~4000 feet per minute AT THE TOOL. Enjoy!!

http://www.shopsmithacademy.com/SS_Archives/SS109/SS109_Dust_Collection.htm

[quote="JPG40504"]Do not worry about pi when comparing! Just remember the radius squared. Thus if the radius doubles, the area quadruples. If dealing with diameters(pizza) the same holds true. i.e. 12" pizza vs 6" pizza [6x6 vs 3x3 ==36 vs 9 == 4x!]

It is the RATIO SQUARED that is relevant. Thus a 6" vs a 18" has a RATIO of 3:1]

Not too shabby for an electrical engineer!! Your 100% right for the quick and dirty way of comparing things to estimate the difference. I've been doing it this way since birth......go for the 3" baby bottle vs. the 2". (~2-1/4 times more juice!

mickyd wrote:Hi Mark,

Welcome to the forum. You have definitely come to the right place to get you questions answered. You'll see there is a lot of expertise in this forum in all different areas.

This ShopSmith video link below will tell you all you need to know plus more for correctly designing a dust collection system.

The critical design specifications to maintain for proper dust collection is the VELOCITY OF THE AIR STREAM and STATIC PRESSURE You'll see that your looking for a system that gives you at least ~4000 feet per minute AT THE TOOL. Enjoy!!

http://www.shopsmithacademy.com/SS_Archives/SS109/SS109_Dust_Collection.htm

Where does one get the SP drop data on various pipe/fittings???

JPG40504 wrote:Where does one get the SP drop data on various pipe/fittings???

From the blackboard
http://www.shopsmithacademy.com/SS_Arch ... ection.pdf