dust collector questions

[Bama]

After years of making knives I shutdown and cleaned my shop and decided to install a dust collector. I bought the Harbor Freight dust collector and I'm going to build a spark arrestor
bucket My question is on hose size you can use 4" or 2" is 2" sufficient for one grinder or would using 4" pull more dust?

 

[Stacy E. Apelt - Bladesmith]

The more the airflow volume the lower the air speed. 4" moves the same amount of air at 1/4 the speed of a 2" hose ( inverse proportional of the square), and thus is better in a case like dust extraction and ventilation. For vacuuming a floor or the bench, use a 2" hose plugged into the 4" duct with an adapter. This will increase the air speed at the nozzle, and such things up better.

 

[Bama]

Thanks Stacy