Dust Extraction - Impact of reucing 100mm to 62mm

[prologus]

Hi Everyone,

I suspect that this is an old chestnut, but I can't find the answer among the existing posts.

I have a floor standing Woodstar extractor with a 100mm outlet. It is connected to my router table, table saw and bandsaw, all of the ducting running at floor level. Until recently I had the 100mm running up to the three machines and changing down to 62mm for the final connection, say the last 50cm or so. The router blast gate is within 75cm of the table, but the gates for the saws are very close to the extractor itself. On taking the ducting apart I found a great deal of sawdust and fine chippings in the 100mm pipe. What might have caused this? Does reducing the pipe diameter reduce the airflow?

Any thoughts?

 

[Hudson Carpentry]

You always get some chippings an dust resting in the pipes regardless but reducing 100mm down to 62mm will reduce its effectiveness with these floor standing type machines. For 62mm systems you really need a vacuum type of extractor.