Dust collection would be simple if every tool used the same port size. They do not. Tool makers change port sizes between models, and sometimes within one model line. A chart that lists sizes by brand is a guess. The only number that counts is the one you measure on your own tool.
Why There Is No Standard
No rule says what size a dust port has to be. Each maker picks a size, a shape, and a wall thickness. Some ports are round. Some are oval. Some are a shaped nozzle that is not round at all. Two tools from the same maker can differ, and a new model can change the port.
That is why a size on a box or a spec sheet is not enough. It may be a trade name and not a measured size. It may be an inside number or an outside number. It may describe a different version of the tool.
Hose and Duct Sizes You Will See
Hoses and ducts are easier. Most shop vac hoses are sold as 1-1/4 inch, 1-7/8 inch, or 2-1/2 inch. Dedicated dust collectors and central systems usually run 4 inch hose and duct. Those are trade names, so measure the real end of your own hose.
A 4 inch duct can move far more air than a shop vac hose. A standard shop vac cannot work well with a 4 inch hose. For that size you want a dedicated dust collector or a strong 2-stage unit.
How to Measure a Dust Port
- Look at the dust port on your tool. Is it an opening, or a stub that sticks out?
- If it is an opening, measure across the inside with calipers or a ruler. If it is a stub, measure across the outside.
- Measure the widest point and the narrowest point. If the two numbers differ, the port is not round. Write down both.
- Measure the end of your hose the same way.
Our size guide walks through each step with pictures of where to put the calipers.
What to Do With Your Two Numbers
Give us your tool measurement and your hose measurement. We print the adapter to those numbers. You do not need a chart.
| Where to look | What it is | What to do |
|---|---|---|
| The 1-1/4 in. size page | Tools grouped under this size | Use it as a starting point, then measure yours |
| The 1-1/2 in. size page | Tools grouped under this size | Use it as a starting point, then measure yours |
| The 2-1/2 in. size page | Tools grouped under this size | Use it as a starting point, then measure yours |
| The 4 in. size page | Ducts and collector inlets grouped under this size | Use it as a starting point, then measure yours |
A Note on Fit Quality
Shape varies between makers even when the number looks the same. A generic adapter leaves a gap or needs tape to seal. An adapter printed to your two measurements is sized to the inside of your tool port on one end and your hose on the other. The fit is snug, and you keep strong suction instead of leaking around the joint.
Measure your port, measure your hose, then Build My Adapter.
