Adapter sizing is the most common source of confusion in dust collection. Tool makers change port sizes between models, and shop vac hoses come in a few common sizes. The adapter you need depends on your own two measurements.
This guide shows how to find both numbers and what to do with them.
Step 1: Measure Your Tool's Dust Port
Do not trust a chart. Tool makers change port sizes between models, and sometimes within one line. 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.
Step 2: Measure Your Shop Vac Hose
Shop vacs are usually sold with one of these hose sizes:
- 1-1/4 inch (31.75mm ID), often on compact vacs
- 1-7/8 inch (47.6mm ID), often on mid-size vacs
- 2-1/2 inch (63.5mm ID), often on large vacs
Those are trade names. Check the cuff, the plastic fitting at the end of the hose. The size is usually molded into the plastic. If not, measure the inner diameter of the hose end.
Step 3: Read the Gap Between the Two Numbers
An adapter bridges the gap between your tool port and your hose end. If your tool port is smaller than the hose end, the adapter steps up. If it is larger, the adapter steps down. Large machines such as miter saws and table saws often have larger ports, so a reducer may be what you need. Measure yours before you decide.
Step 4: Connecting to an Extractor
If you want to run a tool through a dust extractor, measure the end of the extractor hose too. Extractor hoses often use their own sizes, and they change from maker to maker. We print the adapter between your tool port and that hose end.
Want a Starting Point?
The port size pages show what we print at each size: the 27mm size page, the 1-1/4 in. size page, the 35mm size page, the 36mm size page, and the 2-1/2 in. size page. They are a place to compare, and your own reading is the number we print to.
Ready to Order?
Give us your tool measurement and your hose measurement in Build My Adapter. Our size guide has pictures of each step.
