Dust Collector

A dust collector pulls chips and dust away from a stationary machine's cutting point through ducting or a direct hose connection, using a squirrel-cage impeller sized for real airflow volume rather than the suction (vacuum pressure) a shop vacuum is built around. That distinction matters more than it sounds like it should: a table saw, jointer, or planer throws a high volume of chips and fine dust that a shop vacuum's small-diameter hose and lower CFM simply can't keep up with, even though a shop vac can out-suction a dust collector at a single small port.

Single-stage vs. two-stage (cyclone)

A single-stage collector pulls everything -- chips and fine dust together -- straight into one filter bag or canister, where the fine dust that clogs a filter fastest ends up mixed in with the bulk of the coarse chips. A two-stage (cyclone) collector spins chips and dust in a separator first, dropping the heavy chips into a bin below and sending only the fine dust on to the filter -- the filter clogs far slower, and the bin empties far less often, at a real added cost and footprint for the cyclone itself.

CFM and why one collector can't feed two machines well

Cubic feet per minute (CFM) is the actual airflow a collector moves, and it drops fast with duct length, elbows, and reduced-diameter fittings between the collector and the machine -- a collector rated for 800 CFM at the impeller might deliver meaningfully less at a far port. Running two machines off one collector at once (a common temptation with a shared duct system) usually starves both below what either needs individually.

A shop vacuum still has a job

Dust collectors are built for a machine's dust port, not for cleanup, hand tools, or a random orbital sander's small port -- a shop vacuum (or a dedicated dust extractor) stays the right tool for those, and most real shops end up running both rather than one instead of the other.

Safety

Fine wood dust is a genuine respiratory hazard with long-term exposure, not just a mess -- a dust collector cuts down what's airborne, but doesn't replace a proper dust mask or respirator for the fine particulate a collector's filter doesn't catch every particle of.