# Dust collector hose size



## CaptRandy (Jan 27, 2011)

Have a 4" dust collector hose, what will be effect if I connect a 2 1/2" hose to end of the 4" run at my lathe station? Will it overheat the unit from too much suction and restricted air flow?


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## mwhals (Apr 13, 2010)

The smaller hose will restrict air flow, but shouldn't cause overheating problems at the dust collector.


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## Locodcdude (Oct 24, 2010)

Hi Randy,
I just posted a thread last night about Dust collection how to's and know hows. You can check it out in this section of the forum. Aside from that:
Putting a 2 1/2 hose on a 4 inch port will restrict air flow A LOT, and you will actually get less suction out of the hose, than you would if it was a 3 or 4 inch hose. Directly off the collector is no good for a 2 1/2 hose, but if you run pipe, and use a few different drops, for some other tools, then have a drop for the 2 1/2 some where, you'll be fine. The machine is made to have 650 - 700 CFM's run through it at a time, give or take a few. Running a 2 1/2" hose would not let it breath properly, as you'll notice, the bag will not inflate all the way, or it may be "limp".
Check out my thread in this section, it will be helpful.
-Hal.


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## CaptRandy (Jan 27, 2011)

I was afraid the drop in diameter would adversely affect the fan and may even cause it to overheat and burn out. I did not plan to use it for extended time period but in small bursts.


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## Locodcdude (Oct 24, 2010)

Yea in small quantities to use it is fine, it won't burn out the fan, but I would highly suggest you use a 4 inch hose instead. You will notice that the suction is not good using a small hose. Like I said, the machine is meant to pull 650 - 700 CFM's, and if it can't, it will not operate as efficiently.


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## BWSmith (Aug 24, 2010)

Be aware that transitioning from one size piping to another size is very important in overall efficiency.I'd no-doubt just confuse all with my hillbilly expanation so,won't.

The thing is,the length of the transition...in your case goin from a 2 1/2 into a 4.....Theres ratios availible if you research that will determine the best length of this transition.It'll be a lot longer than you're thinking.Its a boundry layer thing......also happens right after turns.........the tighter the radius the worse the "seperation" of boundry layer.And explains why two 45*,spread apart with a strght sect. is "usually" better than even a sweep 90*.BW


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## CaptRandy (Jan 27, 2011)

I know from using pressure washers professionally that I lose quite a lot of pressure the longer my hose length. What starts at 3000psi becomes close to 2000 after 300 ft of line. But I was not sure how it would relate to the suction hoses.


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