Hey everyone! I just got a 2HP cyclone dust collector that has a single 6" port and a 4" splitter. But all my machines currently use 4" ports or smaller, including my table saw that has a 2.5" port. I've done some reading, particularly on Bill Pentz's site, but I'm still unsure. He suggests that 6" ducting is ideal, yet he also mentions that if your machines don't have 6" ports, it doesn't do much good. My concern is whether a 6" main trunk will suffice with 4" drops, keeping airspeed consistent enough to handle heavier dust and shavings. Would I be better off using a fully 4" system instead? Any insights would be greatly appreciated!
4 Answers
I’d argue that using different duct sizes can lead to inconsistencies in the airflow characteristics, and restricting airflow is never great. Larger ducts might not pull dust as effectively if your tools can’t accommodate them, making 4" the better option for your current setup. Each tool should be optimized for the duct size it can handle instead of trying to force it all into a bigger system that might not yield the best results!
There's definitely a balance to achieve with duct sizing. If you go too small, you risk clogs. However, I’ve found 4" ducting to work fine in my shop with a 2HP collector. I have a setup with some long runs and minimal issues, but I did add an extra blast gate to manage airflow better. Just make sure you keep the ducting as straight as possible to maintain velocity!
If all your machines have 4" ports, I would definitely go for a 4" trunk. Having a reduction down to 4" from a 6" duct could really limit your CFM and create vacuum issues in the main trunk, which isn’t good. A 4" duct will keep flow more consistent throughout your setup!
Honestly, you should consider using 6" ducting very close to the machines, with a blast gate to split off into 4" ducts from there. This setup can enhance airspeed since both pipes will be in use simultaneously. Just watch out for tools with smaller ports like a 2.5"; they might need a shop vac instead of a dust collector for effective dust removal. My bandsaw has 2 4" ports, and I get great suction that way!
Absolutely! Remember that what's important is the total cross-sectional area. Even though you have smaller ports, having multiple 4" connections can effectively mimic a larger port system.