One of the most confusing parts of setting up dust collection is the hose sizes. Makers use different diameters. Shop vac hoses are not the same as dust extractor hoses. Central dust collection ducts are something else entirely.
This guide covers the common hose and duct diameters and how to measure the one you own.
Shop Vac Hose Sizes
Shop vacs are usually sold with one of three hose sizes, often based on the size of the unit:
| Hose Size | ID | Often Found On |
|---|---|---|
| 1-1/4 inch | 32mm | Small shop vacs |
| 1-7/8 inch | 48mm | Mid-size shop vacs |
| 2-1/2 inch | 63mm | Large shop vacs and pro vacuums |
These are trade names. Real hose ends vary a little from one maker to the next, so measure the one you own.
Dust Extractor Hose Sizes
European-style dust extractors often use metric hoses, and the size changes from maker to maker. They do not match the shop vac sizes above. Some use a clip or a twist lock. Do not trust a chart. Measure the end of the hose that came with your extractor.
Central Dust Collection Duct Sizes
Fixed central dust collectors use smooth-walled PVC or metal duct. The common duct sizes are:
- 4-inch duct: common for cabinet saws, jointers, and planers in home shops
- 5-inch duct: used with some larger single-stage collectors
- 6-inch duct: used with cyclone dust collectors and larger two-stage systems
Portable tools connect to a fixed duct system via flexible hose drops. A typical setup: 4-inch main duct with reducers at each drop, then a smaller flexible hose to the tool.
The Confusing Part: Inside vs. Outside Diameter
Hose sizing specs switch between ID (inside diameter) and OD (outside diameter) depending on what is being measured. Tool ports are often described by their ID. Hose fittings are often described by their OD. Adapters bridge the two.
Quick rule: when the adapter goes inside something, match its OD to the ID of that thing. When something goes inside the adapter, match the ID of the adapter to the OD of that thing.
How to Measure a Hose End
- Take calipers or a ruler.
- Measure across the inside of the open end for the ID.
- Measure across the outside of the end for the OD.
- Write both numbers down and note which is which.
Common Mismatches
These are connection problems that come up often in shop dust collection:
- Shop vac hose to a tool port: the hose end is bigger or smaller than the port. Needs an adapter.
- Shop vac hose to an extractor tool: the two systems use different hose styles. Needs an adapter.
- Large duct to a small shop vac hose: needs a reducer fitting.
- Miter saw chute to a hose: the chute is built for a bag, not a hose. Needs an adapter.
Finding the Right Adapter
Measure your tool port and your hose end. Our size guide shows how. Give us the two numbers in Build My Adapter and we print the adapter to them.
