Dust collection is a subject where the advice in books and the reality of home shop implementation diverge significantly. The books recommend 4-inch main trunk lines, proper velocity at every machine, a cyclone separator before the collector, and static pressure calculations to size the collector for the system. The home shop reality is more often: a shop vac on a hose, a bag collector that needs emptying every session, and a fine dust situation that the collection system is addressing poorly if at all.
We asked readers with established dust collection systems – systems they’d lived with for at least two years – what they wish they’d known before building them. The answers were consistent enough to constitute a practical guide.
Fine dust is the problem, not the chips. A dust collector that captures chips but lets fine dust recirculate through the collection filter back into the shop air is giving you a false sense of protection. HEPA or equivalent filtration (below 1 micron capture) is necessary for real air quality improvement. Aftermarket pleated cartridge filters for most bag-style collectors are available and represent a significant upgrade over the stock felt bags.
The last 6 inches of hose matter most. A perfectly designed 4-inch dust collection system that ends in a 1-1/4-inch machine port is restricted by that final connection. Adapters to maximize port size at every machine are cheap and have a large impact. A 2-1/2-inch hose to a 2-1/2-inch machine port collects dramatically better than a 4-inch hose through a 1-1/4-inch adapter regardless of how large the collector is. What do you wish you’d known about dust collection before building your system? These stories help everyone who hasn’t started yet.