# two 2 1/2 inch equal a 4 inch



## GoNavy429 (Oct 7, 2013)

I am running all my lines for a dust collection system, planning on getting a HF DC unit with 4 inch lines, but my router takes a 2 1/2 inch. I plan on putting a "Y" to the router anyways with one 2 1/2 going to the fence dust port and the other 2 1/2 going under the table into the enclosed space with a funnel under the router to catch anything coming into there, so my question is will the two 2 1/2 inch hoses coming off the 4 inch be ok, or do I need to do this a different way...


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## tvman44 (Dec 8, 2011)

That will be close enough, 4" line is 12.56 sq inches and 2 2 1/2" lines is 9.82 sq. inches. :thumbsup:


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## Toller (Dec 30, 2007)

Its not that simple. Even if two 2.5'' hoses had as much area as 4'' hose (which they don't) they still would have less capacity.
You would dobetter to run 4'' to to the base and 2.5'' to the top.


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## GoNavy429 (Oct 7, 2013)

Toller said:


> Its not that simple. Even if two 2.5'' hoses had as much area as 4'' hose (which they don't) they still would have less capacity.
> You would dobetter to run 4'' to to the base and 2.5'' to the top.


Ya that's what I'm doing it's a 4 inch pipe all the way to the router, but then I need to split it to cover my fence and under the table inside the cabinet, which both use a 2 1/2 inch port. What I was saying is it ok the split off the main 4 inch line. What I was thinking is to use one of these (link below) connect my fence off the 2 1/2 and then reduce the other end of the "Y" at the cabinet port for under the table

http://www.woodcraft.com/Product/20...x?gcsct=0ChMI-Oq4xMb3uwIVwRbnCh0mBAAAGAMgBCgA


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## woodnthings (Jan 24, 2009)

*Most the chips come off the top*

I would use the most powerful hose on the top behind the fence. I use just a shop vac with a 2 1/4" hose. It works great. Yes, some dust falls down below, but the motor exhaust is blowing up ward as well, so they combine to blow the chips into the smaller hose on the fence.


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## tvman44 (Dec 8, 2011)

gonavy, that is what I do on my belt/disc sander and it works good. That is also what I am going to do on my router table as soon as I add a DC point to my fence. Granted 2 2 1/2" does not quiet come up to the area of a 4" line but it works good enough for me using standard size hoses and fittings. 2 3" lines would be better as that would = 14 sq". I would like to see someones results using a 4" line split to 2 4" lines, or better yet a 4" split to 2 3" lines. :thumbsup:


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## Toller (Dec 30, 2007)

GoNavy429 said:


> Ya that's what I'm doing it's a 4 inch pipe all the way to the router, but then I need to split it to cover my fence and under the table inside the cabinet, which both use a 2 1/2 inch port. What I was saying is it ok the split off the main 4 inch line. What I was thinking is to use one of these (link below) connect my fence off the 2 1/2 and then reduce the other end of the "Y" at the cabinet port for under the table
> 
> http://www.woodcraft.com/Product/20...x?gcsct=0ChMI-Oq4xMb3uwIVwRbnCh0mBAAAGAMgBCgA


The splitter is fine, but I would increase the cabinet port to 4".


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