Machine · Shop systemsbeginner~3 min read

Dust collection

Short answer

A shop vac gives high suction through a small hose and suits a router with a dust shoe. A dust collector moves much more air through a large hose and suits bigger machines. Either way, add a cyclone separator so the filter does not clog, and expect to empty it.

Two different machines with different jobs

	Shop vacuum	Dust collector
Airflow	Low volume	High volume
Suction	High static pressure	Lower static pressure
Hose	Small, typically 2 to 2.5 inches	Large, typically 4 inches
Suits	A router dust shoe on a hobby machine	Larger machines, or long duct runs
Noise	Very loud	Loud, lower pitched
Filtration	Good with a HEPA cartridge	Depends entirely on the bag or cartridge fitted

For most hobby CNC, a shop vac with a good filter, a cyclone separator and a well fitted dust shoe is the right answer. The small hose is a good match for the small opening a dust shoe presents.

Get a separator

A cyclone separator sits between the machine and the vacuum and drops the chips into a bucket before they reach the filter. Without one, the filter clogs within a job or two and your suction quietly falls off a cliff, which is one of the sneakier causes of burning and packed cuts.

Empty the bucket before long jobs. A full separator stops separating.
The bucket must be rigid enough not to collapse under vacuum.
Check the filter periodically anyway. Fine dust still gets through.

Hose and airflow

Diameter matters more than length. A restriction anywhere sets the ceiling for the whole system.
Every bend costs airflow. Smooth sweeps beat sharp corners, and smooth bore hose beats corrugated.
Do not neck down. Reducing a 4 inch line to a 2 inch fitting at the machine throws away most of the collector's capacity.
Support the hose so it does not drag on the gantry or pull the shoe sideways. Hose drag is a real source of accuracy problems on light machines.

Dust shoes

The shoe is what decides whether the system works, more than the vacuum does.

Brush length. Long enough to seal against the work, short enough that the bit can still be seen when you need to. Many shoes have a removable or magnetic brush skirt for this reason.
Seal. Air has to come from around the cut. Big gaps mean the vacuum pulls room air instead of chips.
Clearance. The shoe is an obstruction. It can hit clamps, and it limits how close to the edge of the work you can cut.
Height adjustment. The shoe needs to sit near the surface regardless of stock thickness. Fixed height shoes are much less effective on thin material.

Run the first test cut without the shoe

The shoe hides the cut. On unfamiliar material, lift the brush or take the shoe off for the first short test so you can see chips, watch for burning and hear the cut. Put it back once you know the settings are right.

Static

Fast moving dry dust through plastic hose builds static. At best it makes dust cling to everything and gives you a small shock. At worst it discharges into the controller: Carbide 3D say almost all the machine disconnects they see are caused by static from vacuum hoses. Metal hose or a grounding wire run through or along the hose, bonded to the machine frame and the collector at one point, is the usual mitigation. See electrical noise and EMI.

Fine dust and health

The dust you can see is not the dust that hurts you

Chips on the table are a housekeeping problem. The fine particles still floating an hour later are the health problem, and they are the ones a cheap filter passes straight back into the room. Use a good filter, add an air cleaner if you work in an enclosed shop, wear a fitted respirator for long sessions and for MDF, and let the air clear before you unmask. See safety.

Do not use a shop vac to pick up hot chips or anything smouldering, and do not run aluminium chips into a collector full of wood dust.